Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health p... more Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health problem, and sports activity is an established trigger. Although the presence of standard cardiovascular risk factors in the young can link to future morbidity and mortality in adulthood, the potential contribution of these risk factors to SCA in the young has not been evaluated. We prospectively ascertained subjects who experienced SCA between the ages of 5 and 34 years in the Portland, Oregon, metropolitan area (2002-2015, catchment population ≈1 million). We assessed the circumstances, resuscitation outcomes, and clinical profile of subjects who had SCA by a detailed evaluation of emergency response records, lifetime clinical records, and autopsy examinations. We specifically evaluated the association of standard cardiovascular risk factors and SCA, and sports as a trigger for SCA in the young. Of 3775 SCAs in all age groups, 186 (5%) occurred in the young (mean age 25.9±6.8, 67% male)...
Background Recent reports indicate that specific left ventricular (LV) geometric patterns predict... more Background Recent reports indicate that specific left ventricular (LV) geometric patterns predict recurrent ventricular arrhythmias in patients with implantable cardioverter‐defibrillators and reduced left ventricular ejection fraction (LVEF). However, this relationship has not been evaluated among patients at risk of sudden cardiac arrest (SCA) in the general population. Methods and Results Adult SCA cases from the Oregon Sudden Unexpected Death Study were compared with geographic controls with no prior history of SCA. Archived echocardiograms performed closest and prior to the SCA event were reviewed. LV geometry was defined as normal (normal LV mass index [LVMI] and relative wall thickness [RWT]), concentric remodeling (normal LVMI and increased RWT), concentric hypertrophy (increased LVMI and RWT), or eccentric hypertrophy (increased LVMI and normal RWT). Analysis was restricted to those with LVEF ≤40%. A total of 246 subjects were included in the analysis. SCA cases (n=172, 68....
Background: Syncope has been associated with increased risk of sudden cardiac arrest (SCA) in spe... more Background: Syncope has been associated with increased risk of sudden cardiac arrest (SCA) in specific patient populations, such as hypertrophic cardiomyopathy, heart failure, and long QT syndrome, but data are lacking on the risk of SCA associated with syncope among patients with coronary artery disease (CAD), the most common cause of SCA. We investigated this association among CAD patients in the community. Methods: All cases of SCA due to CAD were prospectively identified in Portland, Oregon (population approximately 1 million) as part of the Oregon Sudden Unexpected Death Study 2002-2015, and compared to geographical controls. Detailed clinical information including history of syncope and cardiac investigations was obtained from medical records. Results: 2119 SCA cases (68.4 ± 13.8 years, 66.9% male) and 746 controls (66.7 ± 11.7 years, 67.0% male) were included in the analysis. 143 (6.8%) of cases had documented syncope prior to the SCA. SCA cases with syncope were N 5 years older and had more comorbidities than other SCA cases. After adjusting for clinical factors and left ventricular ejection fraction (LVEF), syncope was associated with increased risk of SCA (OR 2.8; 95%CI 1.68-4.85). When analysis was restricted to subjects with LVEF ≥50%, the risk of SCA associated with syncope remained significantly elevated (adjusted OR 3.1; 95%CI 1.68-5.79). Conclusions: Syncope was associated with increased risk of SCA in CAD patients even with preserved LV function. These findings suggest a role for this clinical marker among patients with CAD and normal LVEF, a large subgroup without any current means of SCA risk stratification.
The Tpeak to Tend (Tpe) interval on the 12-lead electrocardiogram predicts an increased risk of s... more The Tpeak to Tend (Tpe) interval on the 12-lead electrocardiogram predicts an increased risk of sudden cardiac arrest (SCA). There is controversy over whether Tpe would be more useful if corrected for heart rate (Tpec). We evaluated whether the predictive value of Tpe for SCA improves with heart rate correction and sought to determine an optimal cutoff value for Tpec in the context of SCA risk. Cases of SCA (n = 628; mean age 66.4 ± 14.5 years; n = 416, 66.2% men) from the Oregon Sudden Unexpected Death Study with an archived electrocardiogram available prior and unrelated to the SCA event were analyzed. Comparisons were made with control subjects (n = 819; mean age 66.7 ± 11.5 years; n = 559, 68.2% men). The Tpe interval was corrected for heart rate using Bazett (TpecBa) and Fridericia (TpecFd) formulas, and the predictive value of Tpec for SCA was evaluated using logistic regression models. The area under the curve for Tpec predicting SCA improved with both correction formulas. Tp...
Introduction-Improvements in risk stratification for sudden cardiac arrest (SCA) will require dis... more Introduction-Improvements in risk stratification for sudden cardiac arrest (SCA) will require discovery of markers that extend beyond the LV ejection fraction (LVEF). The frontal QRS-T angle has been shown to predict risk of SCA but the value of this marker independent of the LVEF has not been investigated. Methods and Results-Cases of adult SCA with an archived electrocardiogram (12-lead ECG) available before the event, with a computable frontal QRS-T angle, were identified from the Oregon Sudden Unexpected Death Study (Oregon SUDS) ongoing in the Portland, Oregon metro area. A total of 666 SCA cases (mean age 67.2 years; 95% CI, 52.3 to 82.1 years; 68.6% males) were compared to 863 controls (mean age 66.6 years, 55.2 to 78.0 years; 68.1% males; 75.0% had CAD) from the same geographical region. The mean frontal QRS-T angle was wider in cases (74°; 95% CI, 17°-131°) compared to controls (51°; 95% CI, 5°-97° p<0.0001). A frontal QRS-T angle of more than 90° remained associated with increased risk of SCD after adjusting for age, gender, heart rate, prolonged intraventricular conduction, electrocardiographic left ventricular hypertrophy (ECG LVH), baseline comorbidities and left ventricular ejection fraction (LVEF) (OR 2.2; 95% CI, 1.60-3.09; p<0.0001). Conclusion-A wide QRS-T angle greater than 90° is associated with an increased risk of SCA independent of the left ventricular ejection fraction.
Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has be... more Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has been recently associated with increased risk of sudden cardiac death (SCD), but the underlying mechanisms are unknown. We correlated echocardiographic findings with ECG and clinical characteristics to investigate how alterations in cardiac structure and function contribute to this risk marker. Methods and results From the ongoing population-based Oregon Sudden Unexpected Death Study (catchment population 1 million), SCD cases with prior ECG available (n ¼ 627) were compared with controls (n ¼ 801). Subjects with delayed transition at V 5 or later were identified, and clinical and echocardiographic patterns associated with delayed transition were analysed. Delayed transition was present in 31% of the SCD cases and 17% of the controls. These subjects were older and more likely to have cardiovascular risk factors and history of myocardial infarction. Delayed transition was associated with increased left ventricular (LV) mass (122.7 + 40.2 vs. 102.9 + 33.7 g/m 2 ; P , 0.001), larger LV diameter (53.3 + 10.4 vs. 49.2 + 8.0 mm; P , 0.001), and lower LV ejection fraction (LVEF) (46.4 + 15.7 vs. 55.6 + 12.5%; P , 0.001). In multivariate analysis, delayed transition was independently associated with myocardial infarction, reduced LVEF, and LV hypertrophy. The association between delayed transition and SCD was independent of the LVEF (OR 1.57; 95% CI 1.04-2.38; P ¼ 0.032). Conclusion The underpinnings of delayed QRS transition zone extend beyond previous myocardial infarction and reduced LVEF. Since the association with sudden death is independent of these factors, this novel marker of myocardial electrical remodelling should be explored as a potential risk predictor of SCD.
Heart rhythm : the official journal of the Heart Rhythm Society, Jan 14, 2015
Prolongation of initial ventricular depolarization on the 12-lead electrocardiogram (ECG), or del... more Prolongation of initial ventricular depolarization on the 12-lead electrocardiogram (ECG), or delayed intrinsicoid deflection (DID), can indicate left ventricular hypertrophy (LVH). The possibility that this marker could convey distinct risk of sudden cardiac arrest (SCA) has not been evaluated. To evaluate the association of DID and SCA in the community. In the ongoing prospective, population-based Oregon Sudden Unexpected Death Study (Oregon SUDS; catchment area approximately 1 million), SCA cases were compared to geographic controls with no SCA. Archived ECGs (closest and unrelated to SCA event for cases) were evaluated for the presence of DID, defined as ≥0.05 second in leads V5 or V6. Left ventricular (LV) mass and function were evaluated from archived echocardiograms. SCA cases (n = 272, 68.7 ± 14.6 years, 63.6% male) as compared to controls (n = 351, 67.6 ± 11.4 years, 63.3% male) were more likely to have DID on ECG (28.3% vs 17.1%, P = .001). DID was associated with increase...
Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing, 2015
Repolarization abnormalities are associated with ventricular arrhythmias, and published studies r... more Repolarization abnormalities are associated with ventricular arrhythmias, and published studies report that a reversal of T wave polarity (positive or flat T wave) in lead aVR may be linked to increased cardiovascular mortality. We evaluated whether a positive or flat T wave in aVR is a risk marker for sudden cardiac death (SCD). SCD cases from the Oregon Sudden Unexpected Death Study (catchment population ~1 million) were compared to geographic controls with coronary artery disease and no history of SCD. Archived electrocardiograms performed prior and unrelated to the SCD event were evaluated. SCD cases (n = 691, 67.6 ± 14.9 years, 69 % male) were more likely than controls (n = 663, 66.2 ± 11.6 years, 67 % male) to have diabetes (40 vs 32 %; p < 0.01), left ventricular ejection fraction (LVEF) ≤35 % (27 vs 11 %; p < 0.01), prolonged QTc (≥450 ms; 54 vs 28 %; p < 0.01) and positive (19 vs 13 %; p < 0.01) or flat T wave (14 vs 7 %; p < 0.01) in aVR. On multivariable an...
OBJECTIVES This study assessed potential improvement in predicting risk of sudden cardiac death (... more OBJECTIVES This study assessed potential improvement in predicting risk of sudden cardiac death (SCD) by adding selected risk markers from the 12-lead electrocardiogram (ECG) to the measurement of left ventricular ejection fraction (LVEF). BACKGROUND Novel strategies to improve risk stratification for SCD are needed. Given the modest odds associated with most individual risk markers, combining multiple markers may be a useful approach. METHODS From the ongoing Oregon Sudden Unexpected Death Study, SCD cases with pre-event LVEF data available were compared with those of matched control subjects with coronary artery disease. Resting heart rate, QRS duration (QRSD), and JTc intervals were measured from archived ECGs prior to and unrelated to the SCD event. Independent odds of SCD for individual and combined ECG markers were calculated. RESULTS SCD cases (n ¼ 317; 67.9 AE 12.9 years of age) were more likely than controls (n ¼ 317; 67.9 AE 12.8 years of age) to have LVEF #35% (26% vs. 11%, respectively). Mean heart rate, QRSD, and JTc were significantly higher in cases (all p < 0.0001). In adjusted analyses, higher heart rate (odds ratio [OR]: 2.6 [95% confidence interval [CI]: 1.8 to 3.7]), QRSD (OR: 1.5 [95% CI: 1.0 to 2.5]), and JTc (OR: 2.3 [95% CI: 1.6 to 3.4]) were independently associated with SCD. When ECG markers were combined, SCD odds progressively increased with 1 (OR: 3.4 [95% CI: 2.1 to 5.4]) and $2 elevated markers (OR: 6.3 [95% CI: 3.3 to 12.1]). Addition of ECG markers to an adjusted model with LVEF improved discrimination (C statistic improved from 0.642 to 0.724) and net reclassification (by 22.7%; p < 0.0001). CONCLUSIONS Combining selected 12-lead ECG markers with LVEF improves SCD risk prediction and warrants further investigation in prospective studies.
Background-Mitral valve prolapse (MVP) is relatively common in the general population with recent... more Background-Mitral valve prolapse (MVP) is relatively common in the general population with recently reported prevalence of 1% and familial clustering (Framingham Heart Study). However, the association with ventricular arrhythmias and sudden cardiac arrest (SCA) remains controversial. Objective-To ascertain the frequency of MVP among SCA cases in the community and characterize the clinical profile of SCA cases with MVP Methods-SCA cases were prospectively identified in the population-based, Oregon Sudden Unexpected Death Study (population approximately 1 million). Presence of MVP was identified from echocardiograms performed prior but unrelated to the SCA event. The detailed clinical profile of SCA cases with MVP was compared to those without MVP to identify potential differences. Results-729 SCA cases were evaluated over a 12 year period (69.5 ± 14.8 years; 64.6% male). MVP was seen in 17 cases pre-arrest (2.3%; 95% CI 1.2 to 3.4%). Mitral regurgitation (MR) was present in 14 (82.3%) MVP-SCA cases, and was moderate or severe in 10 (58.8%). Compared to cases without MVP, MVP-SCA cases were younger (60.9 ± 16.4 vs 69.7 ± 14.7; p=0.02), with fewer risk factors (diabetes 5.9% vs 46.4%; p=0.001; hypertension 41.2% vs 78.9%; p=0.001) or known coronary disease (29.4% vs 65.6%; p<0.001).
Background— Sudden cardiac arrest (SCA) is a major contributor to mortality, but data are limited... more Background— Sudden cardiac arrest (SCA) is a major contributor to mortality, but data are limited among nonwhites. Identification of differences in clinical profile based on race may provide opportunities for improved SCA prevention. Methods and Results— In the ongoing Oregon Sudden Unexpected Death Study (SUDS), individuals experiencing SCA in the Portland, OR, metropolitan area were identified prospectively. Patient demographics, arrest circumstances, and pre-SCA clinical profile were compared by race among cases from 2002 to 2012 (for clinical history, n=126 blacks, n=1262 whites). Incidence rates were calculated for cases from the burden assessment phase (2002–2005; n=1077). Age-adjusted rates were 2-fold higher among black men and women (175 and 90 per 100 000, respectively) compared with white men and women (84 and 40 per 100 000, respectively). Compared with whites, blacks were >6 years younger at the time of SCA and had a higher prearrest prevalence of diabetes mellitus (...
Circulation. Arrhythmia and electrophysiology, 2013
Among patients with epilepsy, sudden cardiac arrest (SCA) is a major cause of death. It is common... more Among patients with epilepsy, sudden cardiac arrest (SCA) is a major cause of death. It is commonly thought that SCA in epilepsy occurs after a seizure, though the strength of evidence supporting this is limited. We sought to evaluate the relationship between seizures and SCA in patients with epilepsy. From the ongoing Oregon Sudden Unexpected Death Study, cases of SCA identified using prospective, multisource ascertainment (Portland metropolitan area, Oregon; population≈1 million; February 1, 2002, to March 1, 2012) were evaluated for history of epilepsy. In the subset with witnessed SCA, clinical presentations were analyzed for evidence of seizure activity immediately before the event as well as lifetime clinical history, including nature of seizures before SCA. Only 34% of patients with history of epilepsy and a witnessed arrest had evidence of seizure activity before the arrest. Rates of survival to hospital discharge after attempted resuscitation were 2.7% in patients with hist...
Journal of the American Heart Association, Jan 11, 2015
Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); howeve... more Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); however, identifying the obese patient at highest risk remains a challenge. We evaluated the association between QRS fragmentation on the 12-lead electrocardiogram and SCD, in obese/overweight subjects. In the ongoing prospective, community-based Oregon Sudden Unexpected Death Study (population approximately 1 million), we performed a case-control analysis, comparing obese/overweight SCD victims with obese/overweight controls from the same geographic region. Archived ECGs prior and unrelated to the SCD event were used for cases and all ECG measurements were assessed in blinded fashion. Fragmentation was defined as the presence of RSR' patterns and/or notching of the R/S wave in at least 2 contiguous leads. Analysis was limited to ECGs with QRS duration <120 ms. Overall prevalence of fragmentation was higher in cases (n=185; 64.9±13.8 years; 67.0% male) compared with controls (n=405; 64....
Circulation: Arrhythmia and Electrophysiology, 2011
Background— Early studies indicate that prolongation of the interval between the peak and the end... more Background— Early studies indicate that prolongation of the interval between the peak and the end of the T wave (Tpeak to Tend [TpTe]) on the 12-lead ECG is a marker of ventricular arrhythmogenesis. However, community-based studies have not been conducted. Methods and Results— TpTe and other ECG predictors were evaluated in the ongoing Oregon Sudden Unexpected Death Study based in the Portland, Oregon, metropolitan area using a case-control design. Cases of sudden cardiac death (SCD) (n=353; mean age, 66.6 years; 95% CI, 65.1 to 68.1 years; 67% men) were compared with living controls with coronary artery disease (n=342; mean age, 64.7 years; 95% CI, 63.4 to 66.0 years; 69% men) from the same region. Analysis of TpTe and selected ECG intervals was limited to sinus rhythm 12-lead ECGs. For cases, these were obtained before and unrelated to SCD. Independent-samples t tests and multiple logistic regression were used. Mean TpTe was significantly greater in cases (89.4 ms; 95% CI, 87.7 to...
Background-Sex hormones are known to have significant effects on pathophysiology of cardiovascula... more Background-Sex hormones are known to have significant effects on pathophysiology of cardiovascular disease. Objective-To study the association between sex hormone levels and sudden cardiac arrest (SCA). Methods-In the ongoing Oregon Sudden Unexpected Death Study (catchment population approximately 1 million), cases of SCA were compared with matched controls. Testosterone and estradiol levels were measured from blood samples drawn at the time of the SCA event in cases and during a routine visit in controls. Results-Among cases (n=149; 64.1 ± 11.7 years; 73.2% male), compared to controls (n=149; 64.2 ±11.6 years; 72.5% male), median testosterone levels were significantly lower in males (4.4 vs. 5.4 ng/ml; p=0.01). Median estradiol levels were higher in male (68 vs. 52 pg/ml; p<0.001) and female cases (54 vs. 36 pg/ml; p<0.001). In multivariate analysis, higher testosterone levels were associated with lower SCA odds only in males (OR 0.75; 95% CI 0.58-0.96; p=0.02). Higher estradiol levels were associated with higher SCA odds in both males (OR 2.0; 95% CI 1.5-2.6; p<0.001) and females (OR 3.5; 95% CI 1.9-6.4; p<0.001). A higher testosterone/estrogen ratio was associated with lower SCA odds in males only (OR 0.5; 95% CI 0.4-0.7; p<0.001). In a canine model of SCA, plasma testosterone levels were not significantly altered by the cardiac arrest event.
The current annual incidence of sudden cardiac death in the US is likely to be in the range of 18... more The current annual incidence of sudden cardiac death in the US is likely to be in the range of 180-250,000 per year. Coinciding with the decreased mortality from coronary artery disease, there is evidence pointing toward a significant decrease in rates of sudden cardiac death in the US during the second half of the twentieth century. However the alarming rise in prevalence of obesity and diabetes in the first decade of the new millennium both in the US and worldwide, would indicate that this favorable trend is unlikely to persist. We are likely to witness a resurgence of coronary artery disease and heart failure, as a result of which sudden cardiac death will have to be confronted as a shared and indiscriminate, worldwide public health problem. There is also increasing recognition of the fact that discovery of meaningful and relevant risk stratification and prevention methodologies will require careful prospective community-wide analyses, with access to large archives of DNA, serum and tissue that link with well-phenotyped databases. The purpose of this review is to summarize current knowledge of sudden cardiac death epidemiology. We will discuss the significance and strengths of community-wide evaluations of sudden cardiac death, summarize recent observations from such studies, and finally highlight specific potential predictors that warrant further evaluation as determinants of sudden cardiac death in the general population.
Background: Recent genome-wide association studies (GWAS) have identified novel loci associated w... more Background: Recent genome-wide association studies (GWAS) have identified novel loci associated with sudden cardiac death (SCD). Despite this progress, identified DNA variants account for a relatively small portion of overall SCD risk, suggesting that additional loci contributing to SCD susceptibility await discovery. The objective of this study was to identify novel DNA variation associated with SCD in the context of coronary artery disease (CAD). Methods and Findings: Using the MetaboChip custom array we conducted a case-control association analysis of 119,117 SNPs in 948 SCD cases (with underlying CAD) from the Oregon Sudden Unexpected Death Study (Oregon-SUDS) and 3,050 controls with CAD from the Wellcome Trust Case-Control Consortium (WTCCC). Two newly identified loci were significantly associated with increased risk of SCD after correction for multiple comparisons at: rs6730157 in the RAB3GAP1 gene on chromosome 2 (P = 4.93610 212 , OR = 1.60) and rs2077316 in the ZNF365 gene on chromosome 10 (P = 3.64610 28 , OR = 2.41). Conclusions: Our findings suggest that RAB3GAP1 and ZNF365 are relevant candidate genes for SCD and will contribute to the mechanistic understanding of SCD susceptibility.
Introduction-Sudden cardiac death (SCD) is a large public health problem that warrants ongoing ev... more Introduction-Sudden cardiac death (SCD) is a large public health problem that warrants ongoing evaluation in the general population. While single-year community-based studies have been performed there is a lack of studies that have extended evaluation to multiple years in the same community. Methods and Results-From the ongoing Oregon Sudden Unexpected Death Study, we analyzed prospectively identified SCD cases in Multnomah County, Ore, (population ≈700,000) from February 1, 2002 to January 31, 2005. Detailed information ascertained from multiple sources (first responders, clinical records and medical examiner) was analyzed. A total of 1,175 SCD cases were identified (61% male) with a mean age of 65±18 yrs for men vs. 70±20 for women (P <0.001). The overall incidence rate for the period was 58/100,000 residents/year. Onequarter (24.6%) were ≤55 yrs of age. The most common initial rhythm was ventricular tachycardia or fibrillation (39% of cases, survival 27%) followed by asystole (36%, survival 0.7%) and pulseless electrical activity (23%, survival 6%). Among subjects that underwent resuscitation, the rate of survival to hospital discharge was 12% and overall survival to hospital discharge irrespective of resuscitation was 8%. Of the 68 survivors, 16 (24%) received a secondary prevention ICD. Conclusion-We report annualized SCD incidence from a multiple-year, multiple-source community-based study, with higher than expected rates of women and subjects age ≤55 yrs. The low implantation rate of secondary prevention ICDs is likely to be multifactorial, but there are potential implications for re-calibration of the projected need for ICD implantation; larger and more detailed studies are warranted.
Background-While sudden cardiac arrest (SCA) rates increase with age, middle-aged adults (35-59 y... more Background-While sudden cardiac arrest (SCA) rates increase with age, middle-aged adults (35-59 years) may comprise a significant proportion of SCA cases in the community (30-40%). However, there is a lack of studies evaluating SCA risk factors specifically associated with this age-group of the population. Methods-Using prospective multiple-source surveillance methodology we identified cases of SCA ≥35 years in the ongoing Oregon Sudden Unexpected Death Study (Portland, Oregon metropolitan area, population ≈1,000,000). Out-of-hospital SCA cases, aged 35-59 years were compared to older SCA cases (≥60years) in a comprehensive analysis of clinical profile of SCA. Results-The middle-aged (n=753) compared to older (n=1251) cases were more likely to be male, obese, have sleep apnea and seizure disorder (all p≤0.001); and were less likely to have a history of hypertension, diabetes mellitus, known coronary artery disease, congestive heart failure and syncope (all p<0.01). In multivariable analyses the middle-aged group had higher likelihood of male sex (O.R. 1.67, 95% C.I. 1.29-2.18), obesity (2.20, 1.52-3.19), sleep apnea (2.30, 1.44-3.68) and seizure disorder (2.69, 1.64-4.42); and lower rates of known coronary artery disease (0.57, 0.43-0.74) and congestive heart failure (0.35, 0.25-0.48). Conclusions-SCA in the middle-aged adult was distinguishable from older subjects by higher rates of obesity, sleep apnea and seizure disorder; and lower prevalence of traditional clinical risk markers. With the growing epidemic of obesity, these findings have implications for SCA burden; and suggest the need for a clinical and investigational focus on SCA prediction and prevention in the middle-aged adult, that is distinct from older adults.
Background-Left ventricular hypertrophy (LVH) is associated with increased risk of sudden cardiac... more Background-Left ventricular hypertrophy (LVH) is associated with increased risk of sudden cardiac arrest (SCA); whether LVH diagnosed by 12-lead ECG versus echocardiogram conveys identical or distinct risk information has not been previously evaluated. Objective-To compare the association between ECG versus echocardiographic LVH and SCA in the community. Methods-In a large, prospective population-based study (Oregon SUDS; population approximately one million), cases of SCA were compared to controls recruited from the same geographical area. The association between LVH and SCA was evaluated, specifically comparing LVH diagnosed by ECG versus echocardiogram. Results-Cases (n=132; 66.9 ± 13.5 years; 58.3% male), compared to controls (n= 211; 66.2 ± 12 years; 59.2% male) were more likely to have both ECG LVH (12.1% vs. 5.7%; p=0.03) and echocardiographic LVH (35.0% vs. 15.5%; p<0.001). However, there was poor agreement between the tests (kappa statistic = 0.128). A large subgroup of patients with ECG LVH (57.1%) did not have echocardiographic LVH; conversely 83.6% of patients with echocardiographic LVH did not have ECG LVH. In multivariate analysis, ECG LVH was significantly associated with SCA (OR 2.5; 95% CI 1.1-6.0; p=0.04). When echocardiographic LVH was added to the model, this association was only mildly attenuated (OR 2.4; 95% CI 1.0-6.0; p=0.05) and echocardiographic LVH was also independently associated with SCA (OR 2.7; 95% CI 1.5-4.9; p=0.001).
Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health p... more Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health problem, and sports activity is an established trigger. Although the presence of standard cardiovascular risk factors in the young can link to future morbidity and mortality in adulthood, the potential contribution of these risk factors to SCA in the young has not been evaluated. We prospectively ascertained subjects who experienced SCA between the ages of 5 and 34 years in the Portland, Oregon, metropolitan area (2002-2015, catchment population ≈1 million). We assessed the circumstances, resuscitation outcomes, and clinical profile of subjects who had SCA by a detailed evaluation of emergency response records, lifetime clinical records, and autopsy examinations. We specifically evaluated the association of standard cardiovascular risk factors and SCA, and sports as a trigger for SCA in the young. Of 3775 SCAs in all age groups, 186 (5%) occurred in the young (mean age 25.9±6.8, 67% male)...
Background Recent reports indicate that specific left ventricular (LV) geometric patterns predict... more Background Recent reports indicate that specific left ventricular (LV) geometric patterns predict recurrent ventricular arrhythmias in patients with implantable cardioverter‐defibrillators and reduced left ventricular ejection fraction (LVEF). However, this relationship has not been evaluated among patients at risk of sudden cardiac arrest (SCA) in the general population. Methods and Results Adult SCA cases from the Oregon Sudden Unexpected Death Study were compared with geographic controls with no prior history of SCA. Archived echocardiograms performed closest and prior to the SCA event were reviewed. LV geometry was defined as normal (normal LV mass index [LVMI] and relative wall thickness [RWT]), concentric remodeling (normal LVMI and increased RWT), concentric hypertrophy (increased LVMI and RWT), or eccentric hypertrophy (increased LVMI and normal RWT). Analysis was restricted to those with LVEF ≤40%. A total of 246 subjects were included in the analysis. SCA cases (n=172, 68....
Background: Syncope has been associated with increased risk of sudden cardiac arrest (SCA) in spe... more Background: Syncope has been associated with increased risk of sudden cardiac arrest (SCA) in specific patient populations, such as hypertrophic cardiomyopathy, heart failure, and long QT syndrome, but data are lacking on the risk of SCA associated with syncope among patients with coronary artery disease (CAD), the most common cause of SCA. We investigated this association among CAD patients in the community. Methods: All cases of SCA due to CAD were prospectively identified in Portland, Oregon (population approximately 1 million) as part of the Oregon Sudden Unexpected Death Study 2002-2015, and compared to geographical controls. Detailed clinical information including history of syncope and cardiac investigations was obtained from medical records. Results: 2119 SCA cases (68.4 ± 13.8 years, 66.9% male) and 746 controls (66.7 ± 11.7 years, 67.0% male) were included in the analysis. 143 (6.8%) of cases had documented syncope prior to the SCA. SCA cases with syncope were N 5 years older and had more comorbidities than other SCA cases. After adjusting for clinical factors and left ventricular ejection fraction (LVEF), syncope was associated with increased risk of SCA (OR 2.8; 95%CI 1.68-4.85). When analysis was restricted to subjects with LVEF ≥50%, the risk of SCA associated with syncope remained significantly elevated (adjusted OR 3.1; 95%CI 1.68-5.79). Conclusions: Syncope was associated with increased risk of SCA in CAD patients even with preserved LV function. These findings suggest a role for this clinical marker among patients with CAD and normal LVEF, a large subgroup without any current means of SCA risk stratification.
The Tpeak to Tend (Tpe) interval on the 12-lead electrocardiogram predicts an increased risk of s... more The Tpeak to Tend (Tpe) interval on the 12-lead electrocardiogram predicts an increased risk of sudden cardiac arrest (SCA). There is controversy over whether Tpe would be more useful if corrected for heart rate (Tpec). We evaluated whether the predictive value of Tpe for SCA improves with heart rate correction and sought to determine an optimal cutoff value for Tpec in the context of SCA risk. Cases of SCA (n = 628; mean age 66.4 ± 14.5 years; n = 416, 66.2% men) from the Oregon Sudden Unexpected Death Study with an archived electrocardiogram available prior and unrelated to the SCA event were analyzed. Comparisons were made with control subjects (n = 819; mean age 66.7 ± 11.5 years; n = 559, 68.2% men). The Tpe interval was corrected for heart rate using Bazett (TpecBa) and Fridericia (TpecFd) formulas, and the predictive value of Tpec for SCA was evaluated using logistic regression models. The area under the curve for Tpec predicting SCA improved with both correction formulas. Tp...
Introduction-Improvements in risk stratification for sudden cardiac arrest (SCA) will require dis... more Introduction-Improvements in risk stratification for sudden cardiac arrest (SCA) will require discovery of markers that extend beyond the LV ejection fraction (LVEF). The frontal QRS-T angle has been shown to predict risk of SCA but the value of this marker independent of the LVEF has not been investigated. Methods and Results-Cases of adult SCA with an archived electrocardiogram (12-lead ECG) available before the event, with a computable frontal QRS-T angle, were identified from the Oregon Sudden Unexpected Death Study (Oregon SUDS) ongoing in the Portland, Oregon metro area. A total of 666 SCA cases (mean age 67.2 years; 95% CI, 52.3 to 82.1 years; 68.6% males) were compared to 863 controls (mean age 66.6 years, 55.2 to 78.0 years; 68.1% males; 75.0% had CAD) from the same geographical region. The mean frontal QRS-T angle was wider in cases (74°; 95% CI, 17°-131°) compared to controls (51°; 95% CI, 5°-97° p<0.0001). A frontal QRS-T angle of more than 90° remained associated with increased risk of SCD after adjusting for age, gender, heart rate, prolonged intraventricular conduction, electrocardiographic left ventricular hypertrophy (ECG LVH), baseline comorbidities and left ventricular ejection fraction (LVEF) (OR 2.2; 95% CI, 1.60-3.09; p<0.0001). Conclusion-A wide QRS-T angle greater than 90° is associated with an increased risk of SCA independent of the left ventricular ejection fraction.
Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has be... more Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has been recently associated with increased risk of sudden cardiac death (SCD), but the underlying mechanisms are unknown. We correlated echocardiographic findings with ECG and clinical characteristics to investigate how alterations in cardiac structure and function contribute to this risk marker. Methods and results From the ongoing population-based Oregon Sudden Unexpected Death Study (catchment population 1 million), SCD cases with prior ECG available (n ¼ 627) were compared with controls (n ¼ 801). Subjects with delayed transition at V 5 or later were identified, and clinical and echocardiographic patterns associated with delayed transition were analysed. Delayed transition was present in 31% of the SCD cases and 17% of the controls. These subjects were older and more likely to have cardiovascular risk factors and history of myocardial infarction. Delayed transition was associated with increased left ventricular (LV) mass (122.7 + 40.2 vs. 102.9 + 33.7 g/m 2 ; P , 0.001), larger LV diameter (53.3 + 10.4 vs. 49.2 + 8.0 mm; P , 0.001), and lower LV ejection fraction (LVEF) (46.4 + 15.7 vs. 55.6 + 12.5%; P , 0.001). In multivariate analysis, delayed transition was independently associated with myocardial infarction, reduced LVEF, and LV hypertrophy. The association between delayed transition and SCD was independent of the LVEF (OR 1.57; 95% CI 1.04-2.38; P ¼ 0.032). Conclusion The underpinnings of delayed QRS transition zone extend beyond previous myocardial infarction and reduced LVEF. Since the association with sudden death is independent of these factors, this novel marker of myocardial electrical remodelling should be explored as a potential risk predictor of SCD.
Heart rhythm : the official journal of the Heart Rhythm Society, Jan 14, 2015
Prolongation of initial ventricular depolarization on the 12-lead electrocardiogram (ECG), or del... more Prolongation of initial ventricular depolarization on the 12-lead electrocardiogram (ECG), or delayed intrinsicoid deflection (DID), can indicate left ventricular hypertrophy (LVH). The possibility that this marker could convey distinct risk of sudden cardiac arrest (SCA) has not been evaluated. To evaluate the association of DID and SCA in the community. In the ongoing prospective, population-based Oregon Sudden Unexpected Death Study (Oregon SUDS; catchment area approximately 1 million), SCA cases were compared to geographic controls with no SCA. Archived ECGs (closest and unrelated to SCA event for cases) were evaluated for the presence of DID, defined as ≥0.05 second in leads V5 or V6. Left ventricular (LV) mass and function were evaluated from archived echocardiograms. SCA cases (n = 272, 68.7 ± 14.6 years, 63.6% male) as compared to controls (n = 351, 67.6 ± 11.4 years, 63.3% male) were more likely to have DID on ECG (28.3% vs 17.1%, P = .001). DID was associated with increase...
Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing, 2015
Repolarization abnormalities are associated with ventricular arrhythmias, and published studies r... more Repolarization abnormalities are associated with ventricular arrhythmias, and published studies report that a reversal of T wave polarity (positive or flat T wave) in lead aVR may be linked to increased cardiovascular mortality. We evaluated whether a positive or flat T wave in aVR is a risk marker for sudden cardiac death (SCD). SCD cases from the Oregon Sudden Unexpected Death Study (catchment population ~1 million) were compared to geographic controls with coronary artery disease and no history of SCD. Archived electrocardiograms performed prior and unrelated to the SCD event were evaluated. SCD cases (n = 691, 67.6 ± 14.9 years, 69 % male) were more likely than controls (n = 663, 66.2 ± 11.6 years, 67 % male) to have diabetes (40 vs 32 %; p < 0.01), left ventricular ejection fraction (LVEF) ≤35 % (27 vs 11 %; p < 0.01), prolonged QTc (≥450 ms; 54 vs 28 %; p < 0.01) and positive (19 vs 13 %; p < 0.01) or flat T wave (14 vs 7 %; p < 0.01) in aVR. On multivariable an...
OBJECTIVES This study assessed potential improvement in predicting risk of sudden cardiac death (... more OBJECTIVES This study assessed potential improvement in predicting risk of sudden cardiac death (SCD) by adding selected risk markers from the 12-lead electrocardiogram (ECG) to the measurement of left ventricular ejection fraction (LVEF). BACKGROUND Novel strategies to improve risk stratification for SCD are needed. Given the modest odds associated with most individual risk markers, combining multiple markers may be a useful approach. METHODS From the ongoing Oregon Sudden Unexpected Death Study, SCD cases with pre-event LVEF data available were compared with those of matched control subjects with coronary artery disease. Resting heart rate, QRS duration (QRSD), and JTc intervals were measured from archived ECGs prior to and unrelated to the SCD event. Independent odds of SCD for individual and combined ECG markers were calculated. RESULTS SCD cases (n ¼ 317; 67.9 AE 12.9 years of age) were more likely than controls (n ¼ 317; 67.9 AE 12.8 years of age) to have LVEF #35% (26% vs. 11%, respectively). Mean heart rate, QRSD, and JTc were significantly higher in cases (all p < 0.0001). In adjusted analyses, higher heart rate (odds ratio [OR]: 2.6 [95% confidence interval [CI]: 1.8 to 3.7]), QRSD (OR: 1.5 [95% CI: 1.0 to 2.5]), and JTc (OR: 2.3 [95% CI: 1.6 to 3.4]) were independently associated with SCD. When ECG markers were combined, SCD odds progressively increased with 1 (OR: 3.4 [95% CI: 2.1 to 5.4]) and $2 elevated markers (OR: 6.3 [95% CI: 3.3 to 12.1]). Addition of ECG markers to an adjusted model with LVEF improved discrimination (C statistic improved from 0.642 to 0.724) and net reclassification (by 22.7%; p < 0.0001). CONCLUSIONS Combining selected 12-lead ECG markers with LVEF improves SCD risk prediction and warrants further investigation in prospective studies.
Background-Mitral valve prolapse (MVP) is relatively common in the general population with recent... more Background-Mitral valve prolapse (MVP) is relatively common in the general population with recently reported prevalence of 1% and familial clustering (Framingham Heart Study). However, the association with ventricular arrhythmias and sudden cardiac arrest (SCA) remains controversial. Objective-To ascertain the frequency of MVP among SCA cases in the community and characterize the clinical profile of SCA cases with MVP Methods-SCA cases were prospectively identified in the population-based, Oregon Sudden Unexpected Death Study (population approximately 1 million). Presence of MVP was identified from echocardiograms performed prior but unrelated to the SCA event. The detailed clinical profile of SCA cases with MVP was compared to those without MVP to identify potential differences. Results-729 SCA cases were evaluated over a 12 year period (69.5 ± 14.8 years; 64.6% male). MVP was seen in 17 cases pre-arrest (2.3%; 95% CI 1.2 to 3.4%). Mitral regurgitation (MR) was present in 14 (82.3%) MVP-SCA cases, and was moderate or severe in 10 (58.8%). Compared to cases without MVP, MVP-SCA cases were younger (60.9 ± 16.4 vs 69.7 ± 14.7; p=0.02), with fewer risk factors (diabetes 5.9% vs 46.4%; p=0.001; hypertension 41.2% vs 78.9%; p=0.001) or known coronary disease (29.4% vs 65.6%; p<0.001).
Background— Sudden cardiac arrest (SCA) is a major contributor to mortality, but data are limited... more Background— Sudden cardiac arrest (SCA) is a major contributor to mortality, but data are limited among nonwhites. Identification of differences in clinical profile based on race may provide opportunities for improved SCA prevention. Methods and Results— In the ongoing Oregon Sudden Unexpected Death Study (SUDS), individuals experiencing SCA in the Portland, OR, metropolitan area were identified prospectively. Patient demographics, arrest circumstances, and pre-SCA clinical profile were compared by race among cases from 2002 to 2012 (for clinical history, n=126 blacks, n=1262 whites). Incidence rates were calculated for cases from the burden assessment phase (2002–2005; n=1077). Age-adjusted rates were 2-fold higher among black men and women (175 and 90 per 100 000, respectively) compared with white men and women (84 and 40 per 100 000, respectively). Compared with whites, blacks were >6 years younger at the time of SCA and had a higher prearrest prevalence of diabetes mellitus (...
Circulation. Arrhythmia and electrophysiology, 2013
Among patients with epilepsy, sudden cardiac arrest (SCA) is a major cause of death. It is common... more Among patients with epilepsy, sudden cardiac arrest (SCA) is a major cause of death. It is commonly thought that SCA in epilepsy occurs after a seizure, though the strength of evidence supporting this is limited. We sought to evaluate the relationship between seizures and SCA in patients with epilepsy. From the ongoing Oregon Sudden Unexpected Death Study, cases of SCA identified using prospective, multisource ascertainment (Portland metropolitan area, Oregon; population≈1 million; February 1, 2002, to March 1, 2012) were evaluated for history of epilepsy. In the subset with witnessed SCA, clinical presentations were analyzed for evidence of seizure activity immediately before the event as well as lifetime clinical history, including nature of seizures before SCA. Only 34% of patients with history of epilepsy and a witnessed arrest had evidence of seizure activity before the arrest. Rates of survival to hospital discharge after attempted resuscitation were 2.7% in patients with hist...
Journal of the American Heart Association, Jan 11, 2015
Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); howeve... more Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); however, identifying the obese patient at highest risk remains a challenge. We evaluated the association between QRS fragmentation on the 12-lead electrocardiogram and SCD, in obese/overweight subjects. In the ongoing prospective, community-based Oregon Sudden Unexpected Death Study (population approximately 1 million), we performed a case-control analysis, comparing obese/overweight SCD victims with obese/overweight controls from the same geographic region. Archived ECGs prior and unrelated to the SCD event were used for cases and all ECG measurements were assessed in blinded fashion. Fragmentation was defined as the presence of RSR' patterns and/or notching of the R/S wave in at least 2 contiguous leads. Analysis was limited to ECGs with QRS duration <120 ms. Overall prevalence of fragmentation was higher in cases (n=185; 64.9±13.8 years; 67.0% male) compared with controls (n=405; 64....
Circulation: Arrhythmia and Electrophysiology, 2011
Background— Early studies indicate that prolongation of the interval between the peak and the end... more Background— Early studies indicate that prolongation of the interval between the peak and the end of the T wave (Tpeak to Tend [TpTe]) on the 12-lead ECG is a marker of ventricular arrhythmogenesis. However, community-based studies have not been conducted. Methods and Results— TpTe and other ECG predictors were evaluated in the ongoing Oregon Sudden Unexpected Death Study based in the Portland, Oregon, metropolitan area using a case-control design. Cases of sudden cardiac death (SCD) (n=353; mean age, 66.6 years; 95% CI, 65.1 to 68.1 years; 67% men) were compared with living controls with coronary artery disease (n=342; mean age, 64.7 years; 95% CI, 63.4 to 66.0 years; 69% men) from the same region. Analysis of TpTe and selected ECG intervals was limited to sinus rhythm 12-lead ECGs. For cases, these were obtained before and unrelated to SCD. Independent-samples t tests and multiple logistic regression were used. Mean TpTe was significantly greater in cases (89.4 ms; 95% CI, 87.7 to...
Background-Sex hormones are known to have significant effects on pathophysiology of cardiovascula... more Background-Sex hormones are known to have significant effects on pathophysiology of cardiovascular disease. Objective-To study the association between sex hormone levels and sudden cardiac arrest (SCA). Methods-In the ongoing Oregon Sudden Unexpected Death Study (catchment population approximately 1 million), cases of SCA were compared with matched controls. Testosterone and estradiol levels were measured from blood samples drawn at the time of the SCA event in cases and during a routine visit in controls. Results-Among cases (n=149; 64.1 ± 11.7 years; 73.2% male), compared to controls (n=149; 64.2 ±11.6 years; 72.5% male), median testosterone levels were significantly lower in males (4.4 vs. 5.4 ng/ml; p=0.01). Median estradiol levels were higher in male (68 vs. 52 pg/ml; p<0.001) and female cases (54 vs. 36 pg/ml; p<0.001). In multivariate analysis, higher testosterone levels were associated with lower SCA odds only in males (OR 0.75; 95% CI 0.58-0.96; p=0.02). Higher estradiol levels were associated with higher SCA odds in both males (OR 2.0; 95% CI 1.5-2.6; p<0.001) and females (OR 3.5; 95% CI 1.9-6.4; p<0.001). A higher testosterone/estrogen ratio was associated with lower SCA odds in males only (OR 0.5; 95% CI 0.4-0.7; p<0.001). In a canine model of SCA, plasma testosterone levels were not significantly altered by the cardiac arrest event.
The current annual incidence of sudden cardiac death in the US is likely to be in the range of 18... more The current annual incidence of sudden cardiac death in the US is likely to be in the range of 180-250,000 per year. Coinciding with the decreased mortality from coronary artery disease, there is evidence pointing toward a significant decrease in rates of sudden cardiac death in the US during the second half of the twentieth century. However the alarming rise in prevalence of obesity and diabetes in the first decade of the new millennium both in the US and worldwide, would indicate that this favorable trend is unlikely to persist. We are likely to witness a resurgence of coronary artery disease and heart failure, as a result of which sudden cardiac death will have to be confronted as a shared and indiscriminate, worldwide public health problem. There is also increasing recognition of the fact that discovery of meaningful and relevant risk stratification and prevention methodologies will require careful prospective community-wide analyses, with access to large archives of DNA, serum and tissue that link with well-phenotyped databases. The purpose of this review is to summarize current knowledge of sudden cardiac death epidemiology. We will discuss the significance and strengths of community-wide evaluations of sudden cardiac death, summarize recent observations from such studies, and finally highlight specific potential predictors that warrant further evaluation as determinants of sudden cardiac death in the general population.
Background: Recent genome-wide association studies (GWAS) have identified novel loci associated w... more Background: Recent genome-wide association studies (GWAS) have identified novel loci associated with sudden cardiac death (SCD). Despite this progress, identified DNA variants account for a relatively small portion of overall SCD risk, suggesting that additional loci contributing to SCD susceptibility await discovery. The objective of this study was to identify novel DNA variation associated with SCD in the context of coronary artery disease (CAD). Methods and Findings: Using the MetaboChip custom array we conducted a case-control association analysis of 119,117 SNPs in 948 SCD cases (with underlying CAD) from the Oregon Sudden Unexpected Death Study (Oregon-SUDS) and 3,050 controls with CAD from the Wellcome Trust Case-Control Consortium (WTCCC). Two newly identified loci were significantly associated with increased risk of SCD after correction for multiple comparisons at: rs6730157 in the RAB3GAP1 gene on chromosome 2 (P = 4.93610 212 , OR = 1.60) and rs2077316 in the ZNF365 gene on chromosome 10 (P = 3.64610 28 , OR = 2.41). Conclusions: Our findings suggest that RAB3GAP1 and ZNF365 are relevant candidate genes for SCD and will contribute to the mechanistic understanding of SCD susceptibility.
Introduction-Sudden cardiac death (SCD) is a large public health problem that warrants ongoing ev... more Introduction-Sudden cardiac death (SCD) is a large public health problem that warrants ongoing evaluation in the general population. While single-year community-based studies have been performed there is a lack of studies that have extended evaluation to multiple years in the same community. Methods and Results-From the ongoing Oregon Sudden Unexpected Death Study, we analyzed prospectively identified SCD cases in Multnomah County, Ore, (population ≈700,000) from February 1, 2002 to January 31, 2005. Detailed information ascertained from multiple sources (first responders, clinical records and medical examiner) was analyzed. A total of 1,175 SCD cases were identified (61% male) with a mean age of 65±18 yrs for men vs. 70±20 for women (P <0.001). The overall incidence rate for the period was 58/100,000 residents/year. Onequarter (24.6%) were ≤55 yrs of age. The most common initial rhythm was ventricular tachycardia or fibrillation (39% of cases, survival 27%) followed by asystole (36%, survival 0.7%) and pulseless electrical activity (23%, survival 6%). Among subjects that underwent resuscitation, the rate of survival to hospital discharge was 12% and overall survival to hospital discharge irrespective of resuscitation was 8%. Of the 68 survivors, 16 (24%) received a secondary prevention ICD. Conclusion-We report annualized SCD incidence from a multiple-year, multiple-source community-based study, with higher than expected rates of women and subjects age ≤55 yrs. The low implantation rate of secondary prevention ICDs is likely to be multifactorial, but there are potential implications for re-calibration of the projected need for ICD implantation; larger and more detailed studies are warranted.
Background-While sudden cardiac arrest (SCA) rates increase with age, middle-aged adults (35-59 y... more Background-While sudden cardiac arrest (SCA) rates increase with age, middle-aged adults (35-59 years) may comprise a significant proportion of SCA cases in the community (30-40%). However, there is a lack of studies evaluating SCA risk factors specifically associated with this age-group of the population. Methods-Using prospective multiple-source surveillance methodology we identified cases of SCA ≥35 years in the ongoing Oregon Sudden Unexpected Death Study (Portland, Oregon metropolitan area, population ≈1,000,000). Out-of-hospital SCA cases, aged 35-59 years were compared to older SCA cases (≥60years) in a comprehensive analysis of clinical profile of SCA. Results-The middle-aged (n=753) compared to older (n=1251) cases were more likely to be male, obese, have sleep apnea and seizure disorder (all p≤0.001); and were less likely to have a history of hypertension, diabetes mellitus, known coronary artery disease, congestive heart failure and syncope (all p<0.01). In multivariable analyses the middle-aged group had higher likelihood of male sex (O.R. 1.67, 95% C.I. 1.29-2.18), obesity (2.20, 1.52-3.19), sleep apnea (2.30, 1.44-3.68) and seizure disorder (2.69, 1.64-4.42); and lower rates of known coronary artery disease (0.57, 0.43-0.74) and congestive heart failure (0.35, 0.25-0.48). Conclusions-SCA in the middle-aged adult was distinguishable from older subjects by higher rates of obesity, sleep apnea and seizure disorder; and lower prevalence of traditional clinical risk markers. With the growing epidemic of obesity, these findings have implications for SCA burden; and suggest the need for a clinical and investigational focus on SCA prediction and prevention in the middle-aged adult, that is distinct from older adults.
Background-Left ventricular hypertrophy (LVH) is associated with increased risk of sudden cardiac... more Background-Left ventricular hypertrophy (LVH) is associated with increased risk of sudden cardiac arrest (SCA); whether LVH diagnosed by 12-lead ECG versus echocardiogram conveys identical or distinct risk information has not been previously evaluated. Objective-To compare the association between ECG versus echocardiographic LVH and SCA in the community. Methods-In a large, prospective population-based study (Oregon SUDS; population approximately one million), cases of SCA were compared to controls recruited from the same geographical area. The association between LVH and SCA was evaluated, specifically comparing LVH diagnosed by ECG versus echocardiogram. Results-Cases (n=132; 66.9 ± 13.5 years; 58.3% male), compared to controls (n= 211; 66.2 ± 12 years; 59.2% male) were more likely to have both ECG LVH (12.1% vs. 5.7%; p=0.03) and echocardiographic LVH (35.0% vs. 15.5%; p<0.001). However, there was poor agreement between the tests (kappa statistic = 0.128). A large subgroup of patients with ECG LVH (57.1%) did not have echocardiographic LVH; conversely 83.6% of patients with echocardiographic LVH did not have ECG LVH. In multivariate analysis, ECG LVH was significantly associated with SCA (OR 2.5; 95% CI 1.1-6.0; p=0.04). When echocardiographic LVH was added to the model, this association was only mildly attenuated (OR 2.4; 95% CI 1.0-6.0; p=0.05) and echocardiographic LVH was also independently associated with SCA (OR 2.7; 95% CI 1.5-4.9; p=0.001).
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