Atrial Fibrillation

Abstract—The cardiovascular signs and symptoms,of thyroid disease are some of the most profound and clinically relevant findings that accompany,both hyperthyroidism,and hypothyroidism. On the basis of the understanding of the cellular mechanisms of thyroid hormone action on the heart and cardiovascular system, it is possible to explain the changes in cardiac output, cardiac contractility, blood pressure, vascular resistance, and rhythm disturbances

Intracardiac echocardiography is emerging as a potentially useful tool during RF ablation procedures. There are a number of potential benefits of direct endocardial visualization during RF ablation including: (1) precise anatomical localization of the ablation catheter tip in relation to important endocardial structures, which cannot be visualized with fluoroscopy; (2) reduction in fluoroscopy time; (3) evaluation of catheter tip tissue contact; (4) confirmation of lesion formation and identification of lesion size and continuity; (5) immediate identification of complications; and (6) as a research tool to help in understanding the critical role played by specific endocardia! structures in arrhythmogenesis. This article will review existing data and speculate as to possible future roles for intracardiac echocardiography in interventional electrophysiology.

Background-Blockade of inward-rectifier K + channels by chloroquine terminates reentry in cholinergic atrial fibrillation (AF). However, it is unknown whether inward-rectifier K + channels and reentry are also important in maintaining stretchinduced AF (SAF). We surmised that reentry underlies SAF, and that abolishing reentry with chloroquine terminates SAF more effectively than traditional Na +-channel blockade by flecainide. Methods and Results-Thirty Langendorff-perfused sheep hearts were exposed to acute and continuous atrial stretch, and mapped optically and electrically. AF dynamics were studied under control and during perfusion of either chloroquine (4 µmol/L, n=7) or flecainide (2-4 µmol/L, n=5). Chloroquine increased rotor core size and decreased reentry frequency from 10.6±0.7 Hz in control to 6.3±0.7 Hz (P<0.005) just before restoring sinus rhythm (7/7). Flecainide had lesser effects on core size and reentry frequency than chloroquine and did not restore sinus rhythm (0/5). Specific I Kr blockade by E-4031 (n=7) did not terminate AF when frequency values were >8 Hz. During pacing (n=11), flecainide reversibly reduced conduction velocity (≈30% at cycle length 300, 250, and 200 ms; P<0.05) to a larger extent than chloroquine (11% to 19%; cycle length, 300, 250, and 200 ms; P<0.05). Significant action potential duration prolongation was demonstrable only for chloroquine at cycle length 300 (12%) and cycle length 250 ms (9%) (P<0.05). Conclusions-Chloroquine is more effective than flecainide in terminating SAF in isolated sheep hearts by significantly increasing core size and decreasing reentry frequency. Chloroquine's effectiveness may be explained by its inwardrectifier K + channel blockade profile and suggest that reentry is important to maintain acute SAF.

Aims We investigated the presence and clinical outcome of inducibility of atrial tachyarrhythmias after circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF). Methods and results Sixty patients with symptomatic PAF underwent CPVI guided by 3D mapping and double Lasso technique. After achievement of CPVI, the induction was performed. The left atrium (LA) volume and the isolated LA area around the right and left-sided pulmonary veins were measured by the 3D mapping system. Sustained atrial tachyarrhythmias (.10 min) were induced after CPVI in 17 of 60 patients (28%). Patients with inducible atrial tachyarrhythmias had significantly smaller isolated areas when compared with the group with non-inducible tachyarrhythmias (16.7 + 2.3 vs. 18.8 + 2.9%, P , 0.05). After the initial procedure, recurrence occurred in 18 of 43 (42%) patients in the non-inducible group and in 7 of 17 (41%) in the inducible group during follow-up. A repeat procedure was performed in all 25 patients with recurrence. Five patients had a recurrence after the repeat procedure during 20.8 + 7.5 months, and there was no difference between the two groups. Conclusion Inducibility of atrial tachyarrhythmias is associated with proportionally smaller isolated area and does not predict the clinical efficacy of CPVI in patients with PAF.

Therapy with bisphosphonates, including alendronate (ALN), is considered a safe and effective treatment for osteoporosis. However, recent studies have reported an unexpected increase in serious atrial fibrillation (AF) in patients treated with bisphosphonates. The mechanism that explains this side effect remains unknown. Since AF is associated with an altered sarcoendoplasmic reticulum calcium load, we studied how ALN affects cardiomyocyte calcium homeostasis and protein isoprenylation in vitro. Acute and long-term (48 h) treatment of atrial and ventricular cardiomyocytes with ALN (10 − 8 -10 − 6 M) was performed. Changes in calcium dynamics were determined by both fluorescence measurement of cytosolic free Ca 2+ concentration and western blot analysis of calcium-regulating proteins. Finally, effect of ALN on protein farnesylation was also identified. In both atrial and ventricular cardiomyocytes, ALN treatment delayed and diminished calcium responses to caffeine. Only in atrial cells, long-term exposure to ALN-induced transitory calcium oscillations and led to the development of oscillatory component in calcium responses to caffeine. Changes in calcium dynamics were accompanied by changes in expression of proteins controlling sarcoendoplasmic reticulum calcium. In contrast, ALN minimally affected protein isoprenylation in these cells. In summary, treatment of atrial cardiomyocytes with ALN-induced abnormalities in calcium dynamics consistent with induction of a self-stimulatory, pacemaker-like behavior, which may contribute to the development of cardiac side effects associated with these drugs.

Both resting tachycardia and irregular ventricular rhythm may contribute to impaired cardiac performance in atrial fibrillation (AF). This study assesses the relation between resting heart rate and beat-to-beat changes in left ventricular (LV) ejection and filling in patients with normal and impaired LV systolic function. Beat-to-beat variation in LV outflow and inflow velocity-time integral was measured using pulsed Doppler ultrasound in 39 patients with chronic AF and normal (n ‫؍‬ 22) or impaired (n ‫؍‬ 17) LV systolic function. Aortic velocity-time integral variability increased with mean heart rate (p ‫؍‬ 0.003) even though RR interval variability decreased (p <0.001). Aortic velocity-time integral was more sensitive to the duration of both the preceding (p <0.001) and prepreceding (p <0.001) RR intervals at higher heart rates. These relations were similar for patients with normal and impaired LV systolic function. The sensitivity of the filling velocity-time integral to RR interval variability also increased with heart rate (p <0.001). However, at higher heart rates the filling velocity-time integral (p ‫؍‬ 0.009 ) and filling time (p ‫؍‬ 0.005) were less sensitive to change in RR intervals in patients with impaired LV function. We conclude that beat-to-beat stroke volume variability in AF increases with heart rate. Stroke volume variability was not influenced by LV systolic function.

Atrial fibrillation (AF) is the most common cardiac arrhythmia requiring medical therapy, and present treatment modalities are inadequate. Over the past few years, we have learned a great deal about the phenomenon of electrical remodeling, by which rapid atrial activation leads to changes in atrial electrical properties that promote AF initiation and maintenance. This knowledge opens up the possibility that electrical remodeling may itself be a novel therapeutic target in AF. The present paper reviews what is known about the basic mechanisms of atrial electrical remodeling and then discusses the experimental and clinical evidence that remodeling can be prevented by drug therapy. Despite great potential value, the development of pharmacological interventions to prevent atrial electrical remodeling is still in its infancy.

BACKGROUND Electrophysiological studies in patients with atrial fibrillation demonstrated the presence of electrical conduction between superior and inferior left pulmonary veins (PVs) that makes electrical disconnection of individual PVs difficult. Anatomically, the prevalence, sizes, and locations of the interpulmonary connections have not been investigated systematically.

Introduction: Some patients presenting to emergency departments (EDs) suffer from conditions requiring potentially painful treatment; procedural sedation and analgesia (PSA) are important components of their management. The purpose of this study was to determine the resources used during the administration of PSA. Methods: This prospective observational study was conducted in a Canadian urban teaching center. Detailed data concerning the dosage of PSA medications, adverse events, and ED times for patients requiring PSA for treatment of fractures, reductions of joint dislocations, and cardioversion for atrial fibrillation were collected. Descriptive analyses included proportions, means with standard deviations, and medians with interquartile ranges. Results: Of the 177 PSA cases considered for analysis, 69.5% were orthopedic manipulations and 30.5% were cardioversions. Propofol alone or combined with fentanyl was the commonest medication, and 27 minor adverse events were documented. The median number of staff used in each PSA was 4 (4, 4). The median time from triage to the start of the procedure was 175 minutes (98, 259). The median time from the end of monitoring to discharge was 186 minutes (104, 316). The median time from the start of PSA administration to the end of patient monitoring was 12 minutes for fractures/dislocations and 7 minutes for cardioversion. The total ED length of stay was 6.6 hours.

Introduction: The treatment and outcome of acute myocardial infarction (AMI) has evolved greatly over the past few decades. We compared the mortality and complication rates of patients with AMI admitted to the Coronary Care Unit (CCU) in 2002 to previously reported data. Materials and Methods: All data for AMI patients admitted to National Heart Centre CCU in 2002 were collected through the Singapore Cardiac Data Bank, including demographics, inhospital complications and mortality. These were compared to previous reports from the same institution in 1988, 1975 and 1967. Results: A total of 516 cases with AMI were identified. A higher proportion of patients were aged ≥ ≥ ≥ ≥ ≥70 years in 2002 (31.8%) compared to 1988 (25%), 1975 (11%) and 1967 (5.6%). Acute percutaneous transluminal coronary angioplasty (PTCA) was performed in 250 of 516 (48%) patients in 2002. The overall in-patient and age-standardised mortality was 14.7% and 10% respectively, compared to 20.6% and 17% respectively in 1988 (P = 0.06). For the 250 patients who underwent acute PTCA, overall mortality was 5.2% compared to 24% in those who did not (P <0.001). Common in-hospital complications included heart failure (38%), non-sustained ventricular tachycardia (8%), atrial fibrillation (8%) and complete heart block (6%). Age, heart failure, bundle branch block and sustained ventricular tachycardia were associated with higher mortality by univariate analysis. On multivariate analysis, older age, heart failure and the absence of percutaneous intervention were independently associated with higher mortality. Conclusion: In-hospital mortality for AMI patients admitted to the CCU declined from 1988 to 2002 despite a higher proportion of elderly patients.

Background. Evidence from multiple trials demonstrates the efficacy of prophylactic ␤-blocker, amiodarone, and corticosteroid administration in reducing the incidence of postoperative atrial fibrillation. Despite this information, these interventions remain infrequently or inappropriately utilized. This study was designed to assess the frequency with which these prophylactic strategies are currently being used and to identify concerns and barriers to more widespread application. Methods. A link to an online survey was e-mailed to all practicing cardiac surgeons in Canada. Each surgeon was given a unique log-in identification number to complete the survey online through a secure web page. Results. Surveys were sent to 166 surgeons; 119 completed surveys (72%) were returned. Only 58% of respondents routinely use ␤-blockade for prophylaxis. For nonusers, 44% are unconvinced of the evidence for this practice. The routine use of amiodarone among surgeons was 19%. Of the remainder, 43% cited a perceived increased risk of complications as the reason for not using this therapy. An additional 29% considered the therapy was excessively complicated or time consuming. Corticosteroids were routinely used by only one surgeon. Major barriers to use of steroids were unconvincing evidence (76%), a perceived increased risk of wound infection (38%), and hyperglycemia (30%). Conclusions. Despite level 1 evidence, the use of ␤-blockers, amiodarone, and corticosteroids for prophylaxis of atrial fibrillation among Canadian surgeons remains less than expected. The results of this survey support the need for further clinical trials with robust and clinically relevant outcomes that may further influence surgeons to adopt this practice.

POTENTIAL FINANCIAL CONFLICTS 4. I, my spouse, or one of my dependent children is an employee of a company whose product is being studied. No 5. I, my spouse, or one of my dependent children has significant equity interest (>USD 10,000) in the company that owns the product being studied. No

Center 4 , Sakura, Japan : We analyzed the mortality and morbidity of congenital heart surgery in Japan by using Japan Cardiovascular Surgery Database JCVSD. : The congenital heart surgery performed between January 2017 to December 2018 were obtained from JCVSD. From the data obtained, the most frequent twenty procedures were selected, and the mortalities and major morbidities were analyzed. In addition, all the procedures were classified into STAT Mortality Categories and mortalities in each category were also analyzed. : The mortality of ASD repair and VSD repair were 0% and 0.2% respectively. The mortality of TOF repair, complete AVSD repair, Rastelli operation, CoA complex repair, bidirectional Glenn, TCPC were 2 3%. The mortality of systemic to pulmonary shunt was 4.9%, and the mortality of TAPVC repair and Norwood procedure were 11.1% and 15.7% respectively and not different from the results of 2015 2016. The mortalities according to the STAT categories 1 5 were 0.3%,

Objective: To study the risk factors of cerebral infarction in stroke patients. Methodology: It is a descriptive hospital based study conducted at the Department of Medicine, Naseer Teaching Hospital, Peshawar from January 2005 to December 2005. One hundred patients of stroke with cerebral infarction confirmed on C.T. scan brain and more than twenty years of age were included. Risk factors for cerebral infarction were defined in terms of hypertension, diabetes mellitus, ischemic heart disease, smoking, dyslipidaemia, TIAs (transient ischemic attacks), carotid artery stenosis and family history of stroke. Results: Data of 100 cases with cerebral infarction was recorded. Most of the patients had more than one risk factors for cerebral infarction. hypertension was commonest risk factor (55%), smoking (30%), ischemic heart disease (34%), diabetes mellitus) (26%), hyperlipedaemia (30%), atrial fibrillation (25%), carotid artery stenosis (27%), obesity (15%) and family history of stroke (12%). 39% of patients had physical inactivity. Males were slightly predominant than females (51% vs 49%) and mean age was 50 years. females were rather older with mean age of 53 years. Conclusions: Cerebral infarction accounts for 80 to 85% of cases of stroke, which is a common neurological disorder. It increases a burden of disability and misery for patients and their families. Most of the risk factors of cerebral infarction are modifiable, its prevention should be the main cause of concern for the community.

Introduction and objectives: Atrial fibrillation is associated with substantial morbidity and mortality and both its incidence and prevalence are high. Nevertheless, comprehensive data on this condition in Spain are lacking. The aim of this study was to estimate the prevalence of atrial fibrillation in Spain. Methods: A cross-sectional study was conducted in the general Spanish population older than 40 years. Two-stage random sampling was used, in which first-stage units were primary care physicians randomly selected in every Spanish province and second-stage units were 20 randomly selected persons drawn from each participating physician's assigned population. The reported prevalence was standardized for the age and sex distribution of the Spanish population. The electrocardiogram recordings were read centrally. Results: Overall, 8343 individuals were evaluated. The mean age was 59.2 years (95% confidence interval, 58.6-59.8 years), and 52.4% of the participants were female. The overall age-adjusted prevalence of atrial fibrillation was 4.4% (95% confidence interval, 3.8-5.1). Prevalence was similar in both sexes, men 4.4% (3.6-5.2) and women 4.5% (3.6-5.3), rising with increasing age older than 60 years. In patients older than 80 years, the prevalence was 17.7% (14.1-21.3). In 10% of patients an unknown atrial fibrillation was diagnosed. Conclusions: The prevalence of atrial fibrillation in the general Spanish population older than 40 years is high, at 4.4%. The prevalence is similar in both sexes and rises steeply above 60 years of age. It is estimated that there are over 1 million patients with atrial fibrillation in the Spanish population, of whom over 90 000 are undiagnosed.

The renin-angiotensin-aldosterone system (RAAS) has emerged as an important hormonal system in the initiation and pathogenesis of atrial fibrillation (AF). Therefore, angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) are emerging as novel drugs for the prevention of AF. A meta-analysis of 11 randomized, controlled, parallel-design clinical trials evaluating effect of ACEIs or ARBs on the development of AF was performed. Treatment with ACEIs or ARBs reduced the relative risk (RR) of AF in patients with hypertension by 23% [RR 0.769, P , 0.001, 95% confidence interval (CI) 0.686-0.862] and by 11% in patients after myocardial infarction (RR 0.898, P , 0.05, 95% CI 0.814-0.992). Reduction in AF was greatest in patients after electrical cardioversion (RR 0.491, P , 0.001, 95% CI 0.334-0.720) and in patients with heart failure (RR 0.684, P , 0.001, 95% CI 0.594-0.787). Overall, inhibition of the RAAS reduced the RR of AF by 19% (RR 0.810, P , 0.001, 95% CI 0.759-0.865).

Background— Dabigatran, an oral thrombin inhibitor, and rivaroxaban and apixaban, oral factor Xa inhibitors, have been found to be safe and effective in reducing stroke risk in patients with atrial fibrillation. We sought to compare the efficacy and safety of the 3 new agents based on data from their published warfarin-controlled randomized trials, using the method of adjusted indirect comparisons. Methods and Results— We included findings from 44 535 patients enrolled in 3 trials of the efficacy of dabigatran (Randomized Evaluation of Long-Term Anticoagulation Therapy [RELY]), apixaban (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]), and rivaroxaban (Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation [ROCKET-AF]), each compared with warfarin. The primary efficacy end point was stroke or systemic embolism; the safety end poi...

The cryoballoon catheter ablates atrial fibrillation (AF) triggers in the left atrium (LA) and pulmonary veins (PVs) via transseptal access. The typical transseptal puncture site is the fossa ovalis (FO) - the atrial septum&#39;s thinnest section. A potentially beneficial transseptal site, for the cryoballoon, is near the inferior limbus (IL). This study examines an alternative transseptal site near the IL, which may decrease the frequency of acute iatrogenic atrial septal defect (IASD). Also, the study evaluates the acute pulmonary vein isolation (PVI) success rate utilizing the IL location. 200 patients were evaluated by retrospective chart review for acute PVI success rate with an IL transseptal site. An additional 128 IL transseptal patients were compared to 45 FO transseptal patients by performing Doppler intracardiac echocardiography (ICE) post-ablation to assess transseptal flow after removal of the transseptal sheath. After sheath removal and by Doppler ICE imaging, 42 of 12...

Background: Reports on the prognostic importance of atrial fibrillation following myocardial infarction have provided considerable variation in results. Thus, this study examined the impact of left ventricular systolic function and congestive heart failure on the prognostic importance of atrial fibrillation in acute myocardial infarction patients that might explain previous discrepancies. Methods: The study population was 6676 patients consecutively admitted to hospital with acute myocardial infarction. Information on the presence of atrial fibrillation/flutter, left ventricular systolic function and congestive heart failure were prospectively collected. Mortality was followed for 5 years. Results: In patients with left ventricular ejection fraction b0.25, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.8 (1.1-3.2); pb0.05) but not an increased 30-day mortality. In patients with 0.25Vleft ventricular ejection fractionV0.35, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.7 (1.3-2.3); pb0.001) and an increased 30-day mortality (OR=1.7 (1.3-2.2); pb0.001). In-hospital and 30-day mortality was not increased in patients with left ventricular ejection fraction N0.35. In patients with congestive heart failure, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.5 (1.2-1.9); pb0.001) and increased 30-day mortality (OR=1.4 (1.1-1.7); pb0.001) but not in patients without congestive heart failure. In hospital survivors, atrial fibrillation/atrial flutter was associated with an increased long-term mortality in all subgroups except those with left ventricular ejection fraction b0.25. Conclusions: Atrial fibrillation/atrial flutter is primarily associated with increased in-hospital mortality in heart failure patients. Long-term mortality is increased in all subgroups except those with left ventricular ejection fraction b25%. D

To identify optimum international normalized ratio (INR) levels and required warfarin doses and anticoagulation-related complications in patients following mechanical prosthetic valve replacement. Five hundred and seven patients were prospectively followed up for 10 years (2008.5 patient-years). Anticoagulation-related complications were classified into hemorrhage and thromboembolism. Two hundred and ninety-two (57.6%) were males and 215 (42.4%) were females with a mean age of 29.5 +/- 11.32 years. A total of 268 (52.9%) patients had mitral, 96 (18.9%) had aortic and mitral, and 76 (15%) had aortic valve replacement (AVR). Valves implanted totaled 345 (68%) ball and cage, 126 (24.9%) bileaflet, and 36 (7.1%) single disc. There were 10,669 total visits, with mean INR 2.6 +/- 0.59 and mean warfarin 5.17 +/- 1.6 mg. Sixty-four (3.2% per patient-years) events occurred during follow-up, of which 23 (1.13% per patient-years) events were due to thromboembolism and 41 (2.04% per patient-yea...

This is the first evaluation of dabigatran, an oral direct thrombin inhibitor, in patients with atrial fibrillation (AF). Patients (n ‫؍‬ 502) were randomized to receive blinded doses of 50-, 150-, or 300-mg dabigatran twice daily alone or combined with 81-or 325-mg aspirin or open-label warfarin administered to achieve an international normalized ratio of 2 to 3 for 12 weeks. Dabigatran plasma concentrations, activated partial thromboplastin time, D-dimer, urinary 11-dehydrothromboxane B 2 (DTB2), and liver function were measured at baseline and at 1, 2, 4, 8, and 12 weeks. Clinical end points were assessed according to the treatment received at the time of the event. Overall, 92% of patients completed the study. Major hemorrhages were limited to the group treated with 300-mg dabigatran plus aspirin (4 of 64), and the incidence was significant versus 300-mg dabigatran alone (0 of 105, p <0.02). Total bleeding events were more frequent in the 300-mg (39 of 169, 23%) and 150-mg (30 of 169, 18%) dabigatran groups compared with the 50-mg groups (7 of 107, 7%; p ‫؍‬ 0.0002 and p ‫؍‬ 0.01, respectively). Thromboembolic events were limited to the 50-mg dabigatran dose groups (2 of 107, 2%). The mean trough D-dimer measurements were suppressed for the 2 highest doses of dabigatran and warfarin (international normalized ratio of 2 to 3). Aminotransferase levels >3 times the upper limit of normal were observed in 0.9% of the dabigatran recipients and in none of the warfarin recipients. Two dabigatran recipients had aminotransferase levels >5 times the upper limit of normal as a result of gallstones, which resolved. Trough activated partial thromboplastin time values were 1.2, 1.5, and 1.8 times the baseline level for the 50-, 150-, and 300-mg dabigatran groups, respectively. DTB2 concentrations after 12 weeks of 50-, 150-, and 300-mg dabigatran treatment were increased by 31%, 17%, and 23%, respectively, versus baseline (p ‫؍‬ 0.02, p ‫؍‬ 0.03, and p ‫؍‬ 0.0004). In conclusion, major bleeding events were limited to patients treated with dabigatran 300 mg plus aspirin and thromboembolic episodes were limited to the 50-mg dabigatran groups. The 2 highest doses of dabigatran suppress D-dimer concentrations. Serious liver toxicity was not seen. The significance of the increase of DTB2 concentrations in dabigatran-treated patients needs resolution.

BACKGROUND Circumferential pulmonary vein ablation (CPVA) is an effective treatment for atrial fibrillation (AF). Accurate left atrial (LA) mapping is essential for creating lesions at the LApulmonary vein (PV) junction, avoiding PV stenosis. OBJECTIVES The purpose of this study was to establish whether endocardial impedance varies within the LA and PVs and whether it is a useful tool for mapping and ablation. METHODS Pilot Phase: Three-dimensional LA maps were created using CARTO. Impedance (Z) was measured using a radiofrequency generator at multiple points in the LA, PV ostia (PVO), and deep PVs in 79 patients undergoing their first AF ablation (group 1) and 29 patients undergoing repeat CPVA (group 2). Prospective Phase: In an additional 20 patients, using pilot phase data, one operator defined catheter tip location as either LA or PVO based on CARTO and fluoroscopy. A second operator blinded to CARTO simultaneously did the same based on impedance at 15 Ϯ 4 points per patient. RESULTS Group 1: Z LA was 99.4 Ϯ 9.0 ⍀. Z PVO was higher (109.2 Ϯ 8.5 ⍀), rising further as the catheter advanced into deep PV (137 ⍀ Ϯ 18). Z PVO differed from Z LA by 9 Ϯ 4 ⍀. Group 2 had a lower Z LA and Z PVO compared with group 1 (P Ͻ.05). Impedance monitoring differentiated between LA and PVO, with 91% specificity and sensitivity, 96% positive predictive value, and 81% negative predictive value. At 3-month follow-up, no patients had evidence of PV stenosis on magnetic resonance imaging. CONCLUSION Impedance mapping reliably identifies the LA-PV transitional zone, facilitating AF ablation, and its use is associated with a low incidence of PV stenosis.

Aims Atrial fibrillation patients with prior embolism have a high risk of vascular events in spite of anticoagulant therapy and elderly patients carry an additional risk. We analysed and compared vascular events-rate between older and younger than 75 years atrial fibrillation patients randomized to anticoagulant-alone or combined antiplatelet plus moderate-level anticoagulant therapy. Methods and results A total of 967 patients stratified by age and the history of prior embolism were randomized to therapeutic doses of anticoagulant-alone or combined antithrombotic therapy. Primary events were fatal and non-fatal ischaemic or haemorrhagic stroke/transient ischaemic attack, systemic embolism and myocardial infarction, sudden death and death from bleeding. The elderly, compared with the younger patients, had higher event-rate [hazard ratio 2.31 (95% confidence interval 1.37-3.90), P , 0.003]. The elderly suffered higher severe bleeding event-rate during anticoagulant therapy. The combined, compared with the anticoagulant therapy, reduced the vascular events-rate in the elderly (P ¼ 0.012) and caused less intracranial haemorrhages and less bleeding mortality, although more non-fatal gastric bleeding. Conclusion The elderly with AF had a higher event-rate than the younger patients. A higher severe bleeding event-rate was also registered in elderly patients receiving anticoagulant therapy. Combined, compared with anticoagulant therapy, significantly reduced vascular events and bleeding mortality in elderly patients.

Persons with a clinically recognized myocardial infarction are at increased risk for atrial fibrillation. However a large proportion of all myocardial infarctions remain clinically unrecognized. Whether subjects with electrocardiographic signs of an unrecognized myocardial infarction are also at an increased risk of developing atrial fibrillation is unknown. The objective of this study was to investigate whether unrecognized myocardial infarction was associated with an increased risk of atrial fibrillation in a prospective population-based cohort study. The study is set within the prospective population-based Rotterdam Study. The study population comprised 2505 men and 3670 women without atrial fibrillation at baseline. Participants were classified based on electrocardiography, interview, and clinical data into those with recognized myocardial infarction, those with ECG based unrecognized myocardial infarction and those without myocardial infarction. Atrial fibrillation was ascertained from ECG assessments as well as medical records. During a mean follow-up of 11.7 years (SD 5.0), 329 men and 398 women developed atrial fibrillation. Unrecognized myocardial infarction was associated with a two-fold risk of developing atrial fibrillation in men (HR: 2.21, 95%CI:1.51 to 3.23) compared to men without a history of myocardial infarction, independent of age, and cardiovascular risk factors. In women, unrecognized myocardial infarction was not associated with atrial fibrillation (HR: 0.92, 95%CI:0.59 to 1.44). The presence of an unrecognized myocardial infarction is associated with a twofold increased risk of atrial fibrillation in men, independent of known cardiovascular risk factors.

Over the past decade, there has been an exponential increase in the number of catheter ablation procedures performed for atrial fibrillation (AF). While for paroxysmal AF, proximal pulmonary vein isolation is sufficient in the majority of cases, ablation of persistent and longstanding AF requires an extensive surgical-like procedure. This approach is correlated with a high rate of AF termination; however, this is achieved at the cost of at least one atrial tachycardia (AT) during the index procedure or during the patient's follow-up in the vast majority of cases. As these ATs are often multiple, complex, and frequently more symptomatic than AF, they constitute the last and frequently the most difficult step in ablation for patients with persistent AF. This review concentrates on the practical approaches to the treatment of AT in the context of AF ablation and provides an algorithm that aims at facilitating mapping and ablation strategies using conventional electrophysiological tools.

Objective: To determine cardioversion doses of biphasic DC shock for paediatric atrial dysrhythmias. Design: Prospective recording of energy, pre-shock and post-shock rhythms. Setting: Paediatric hospital. Patients: Shockable atrial dysrhythmias. Main results: Forty episodes of atrial dysrhythmias among 25 children (mean age 6.8 ± 7.1 years, mean weight 28.2 ± 28.5 kg) were treated with external shock. The first shock converted the dysrhythmia to sinus rhythm in 25 episodes. Cardioversion occurred in 2 of 8 (25%) episodes with a dose of <0.5 J/kg, 14 of 16 (88%) with a dose of 0.5-1.0 J/kg and 9 of 16 (56%) with a dose of >1.0 J/kg (p = 0.01, Fisher's exact test). Ten of 15 initially non-responsive episodes were cardioverted with additional shocks at 1.1 ± 0.6 J/kg (range 0.5-2.1 J/kg). Of the remaining 5 unresponsive episodes, 2 of ventricular fibrillation (induced by unsynchronized shock) were successfully defibrillated, and 3 were managed with cardiopulmonary bypass. Among 11 additional children (mean age 4.3 ± 6.8 years, mean weight 18.1 ± 22.0 kg), 18 episodes of atrial dysrhythmias were treated with internal shock which successfully cardioverted all episodes with one or more shocks at 0.4 ± 0.2 J/kg. Conclusions: In rounded doses, recommended initial external cardioversion doses are 0.5-1.0 J/kg and subsequently up to 2 J/kg, internal cardioversion doses are 0.5 J/kg.

The idea of this research is to determine how long in advance can we predict the onset of paroxysmal atrial fibrillation (PAF) from the HRV data. Having established such methods with great confidence it is possible to avert the PAF onset using pacing techniques, thus reliving patient pains.

For most warfarin indications, the target maintenance international normalised ratio (INR) is 2-3. Risk factors for bleeding complications with warfarin use include age, history of past bleeding and specific comorbid conditions. To reverse the effects of warfarin, vitamin K(1) can be given. Immediate reversal is achieved with a prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP). Vitamin K(1) is essential for sustaining the reversal achieved by PCC and FFP. When oral vitamin K(1) is used for warfarin reversal, the injectable formulation of vitamin K(1) is preferable to tablets because of its flexible dosing; this formulation can be given orally or injected. To temporarily reverse the effect of warfarin when there is a need to continue warfarin therapy, vitamin K(1) should be given in a dose that will quickly lower the INR to a safe, but not subtherapeutic, range and will not cause resistance once warfarin is reinstated. Prothrombinex-HT is the only PCC approved in Au...

Prior MI, et al. Treatment of supraventricular tachycardia due to atrioventricular nodal reentry, by radiofrequency catheter ablation of slow-pathway conduction. N Engl J Med 1992;327:313-318. 15. Calkins H, Yong P, Miller JM, Olshansky B, Carlson M, Saul JP, Huang SK, Liem LB, Klein LS, Moser SA, et al. Catheter ablation of accessory pathways, atrioventricular nodal reentrant tachycardia, and the atrioventricular junction: final results of a prospective, multicenter clinical trial. The Atakr Multicenter Investigators Group. Circulation 1999;99:262-270. 16. Langberg JJ, Calkins H, Kim YN, Sousa J, el-Atassi R, Leon A, Borganelli M, Kalbfleisch SJ, Morady F. Recurrence of conduction in accessory atrioventricular connections after initially successful radiofrequency catheter ablation.

PV Ablation for Persistent Atrial Fibrillation. Introduction: Effectiveness of antral pulmonary vein isolation (PVAI) and ablation of non-PV triggers (non-PVTA) in controlling longstanding persistent atrial fibrillation (AF) has not been reported. We sought to describe clinical outcomes with this ablation strategy in patients (pts) followed for at least 1 year.