Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 +/- 11% [overall mean +/- S...
Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricu-lar systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to deter-mine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmo-nary arterial end-systolic pressure in eight of nine patients (23 ± 11 % [overall mean ± S...
Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 ± 11% [overall mean ± SE], ...
The mechanism for the prolongation of P-R interval associated with advancing age is undefined. Us... more The mechanism for the prolongation of P-R interval associated with advancing age is undefined. Using a high-resolution ECG (Marquette MAC-1) to signal average 512 cardiac cycles, we examined 185 healthy volunteers aged 20-83 years from the Baltimore Longitudinal Study of Aging with normal rest and exercise ECGs and a resting P-R interval less than 210 ms. Among the 161 subjects with visible His bundle activity, P-R interval increased with age (p less than .001). This increase was due entirely to prolongation of the interval between the P wave onset and His bundle potential, i.e., the P-H interval, (p less than .001) with no age-associated change in the H-V interval, p = NS. The P-H interval prolongation with age was localized to the P-R segment proximal to His bundle activation (p less than .001). In a separate group of 7 asymptomatic older men (mean age = 71 yr), with first-degree atrioventricular (A-V) block on standard ECG (mean PR = 238 +/- 14 ms), the P-H interval (193 +/- 21, ...
Journal of the American College of Cardiology, 1985
A hemodynamic-radionuclide study was performed to compare the relations between end-systolic pres... more A hemodynamic-radionuclide study was performed to compare the relations between end-systolic pressure and volume in the left and right ventricles in 10 patients with biventricular failure, and to correlate the end-systolic pressure-volume slope with baseline variables of systolic function. During nitroprusside or nitroglycerin infusion, or a combination of both, linear relations were found between end-systolic pressure and volume for both ventricles. In 9 of 10 patients, the end-systolic pressure-volume slope was greater for the left ventricle (mean +/- SD 1.12 +/- 0.36 mm Hg X m2/ml) than for the right ventricle (0.46 +/- 0.27 mm Hg X m2/ml) (p less than 0.001). In all 10 patients, the volume-axis intercept of the pressure-volume relation was greater for the left ventricle (82 +/- 66 ml/m2) than for the right ventricle (2 +/- 30 ml/m2) (p less than 0.005). Right ventricular pressure-volume slope correlated weakly with baseline right ventricular ejection fraction (r = 0.69, p less than 0.05), strongly with the baseline right ventricular end-systolic pressure-volume ratio (r = 0.89) and inversely with baseline right ventricular end-systolic volume (r = -0.86). In conclusion, 1) in patients with severe biventricular failure, changes in systolic pressure influence end-systolic volume more strongly in the right than in the left ventricle. 2) For the right ventricle, the slope of the end-systolic pressure-volume relation is directly related to rest indexes of systolic function. 3) The greater the end-systolic volume at rest, the greater the predicted improvement in right ventricular emptying for any vasodilator-induced reduction in pulmonary artery end-systolic pressure.
Journal of the American College of Cardiology, 1983
The long-term cardiac prognosis of 24 clinically healthy men with complete right bundle branch bl... more The long-term cardiac prognosis of 24 clinically healthy men with complete right bundle branch block, identified from the 1,142 men constituting the population of the Baltimore Longitudinal Study on Aging, was assessed over a follow-up period averaging 8.4 years. When compared with a control group matched for age at which right bundle branch block appeared (mean +/- standard deviation 64.0 +/- 13.5 years), men with right bundle branch block showed no difference in the prevalence of antecedent coronary risk factors or obstructive lung disease. The incidence of angina pectoris, myocardial infarction, valvular heart disease, cardiomegaly, congestive heart failure, advanced heart block or cardiac death in these men did not differ from that of the control group over the observation period. Furthermore, at the latest follow-up study, maximal aerobic exercise tolerance and chronotropic response to maximal exercise were not impaired in men with right bundle branch block relative to control men (9.1 +/- 2.2 versus 7.3 +/- 3.0 minutes and 150.3 +/- 23.5 versus 147.7 +/- 20.7 beats/minute, respectively). However, axis deviation leftward of -30 degrees was present in 46% of men with right bundle branch block but in only 15% of control subjects at latest follow-up (probability [p] less than 0.01). Although the PR interval lengthened by 40 ms or more developed in only 6% of control subjects over the observation period, such prolongation occurred in 29% of men with right bundle branch block (p less than 0.05). These results support the concept that right bundle branch block in these asymptomatic men is a manifestation of a primary abnormality of the cardiac conduction system but has no demonstrable adverse effect on long-term cardiac morbidity or mortality.
The relative contribution of inotropic and vasodilator effect to amrinone-induced hemodynamic imp... more The relative contribution of inotropic and vasodilator effect to amrinone-induced hemodynamic improvement in congestive heart failure (CHF) is unknown. In 9 patients with CHF, the effects of amrinone and nitroprusside on hemodynamic and radionuclide measurements were compared to determine whether reduced afterload accounts for the amrinone-induced decrease in left ventricular end-systolic volume. In each patient, the end-systolic pressure-volume relation was derived using nitroprusside. After terminating nitroprusside treatment, intravenous amrinone (3 mg/kg) caused end-systolic volume to decrease from 148 +/- 32 ml/m2 (mean +/- standard deviation) to 133 +/- 32 ml/m2 (p less than 0.05), causing an increase in cardiac index from 1.9 +/- 0.8 to 2.7 +/- 0.8 liters/min/m2 (p less than 0.001). Arterial end-systolic pressure decreased in all patients during amrinone administration, from 96 +/- 22 to 84 +/- 19 mm Hg (p less than 0.005), as did systemic vascular resistance. Nitroprusside doses needed to match the decrease in LV end-systolic volume induced by amrinone caused significantly greater decreases in arterial end-systolic pressure than did amrinone (p less than 0.01). The amrinone-induced decrease in end-systolic volume exceeded that predicted for a pure vasodilator based on arterial end-systolic pressure and the nitroprusside-derived pressure-volume relation in 6 patients. In 3 patients, the decrease in end-systolic volume did not exceed that expected for a pure vasodilator. In conclusion, after amrinone treatment, afterload reduction occurs in all patients with severe CHF and is the sole effect in some.(ABSTRACT TRUNCATED AT 250 WORDS)
Although vasodilators improve cardiac output in severe left ventricular (LV) failure, the degree ... more Although vasodilators improve cardiac output in severe left ventricular (LV) failure, the degree to which reduction in mitral regurgitation (MR) contributes to this response is unknown. In the present study, nitroprusside-induced changes in forward cardiac output were compared with simultaneous radionuclide LV output in 14 patients with severe LV systolic dysfunction in the absence of known primary valvular disease. Regurgitant output was estimated as LV output minus forward output and regurgitant fraction was calculated as regurgitant output/ LV output. At rest, LV ejection fraction averaged 0.16 4-0.04 (mean 4-standard deviation). Patients were classified into 2 groups based on regurgitant fraction at rest. Group I (n = 5) had little or no detectable valvular regurgitation, with regurgitant fraction less than 0.10; group II (n = 9) had evidence of MR with regurgitant fraction greater than 0.30.
Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 +/- 11% [overall mean +/- S...
Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricu-lar systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to deter-mine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmo-nary arterial end-systolic pressure in eight of nine patients (23 ± 11 % [overall mean ± S...
Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the lef... more Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 ± 11% [overall mean ± SE], ...
The mechanism for the prolongation of P-R interval associated with advancing age is undefined. Us... more The mechanism for the prolongation of P-R interval associated with advancing age is undefined. Using a high-resolution ECG (Marquette MAC-1) to signal average 512 cardiac cycles, we examined 185 healthy volunteers aged 20-83 years from the Baltimore Longitudinal Study of Aging with normal rest and exercise ECGs and a resting P-R interval less than 210 ms. Among the 161 subjects with visible His bundle activity, P-R interval increased with age (p less than .001). This increase was due entirely to prolongation of the interval between the P wave onset and His bundle potential, i.e., the P-H interval, (p less than .001) with no age-associated change in the H-V interval, p = NS. The P-H interval prolongation with age was localized to the P-R segment proximal to His bundle activation (p less than .001). In a separate group of 7 asymptomatic older men (mean age = 71 yr), with first-degree atrioventricular (A-V) block on standard ECG (mean PR = 238 +/- 14 ms), the P-H interval (193 +/- 21, ...
Journal of the American College of Cardiology, 1985
A hemodynamic-radionuclide study was performed to compare the relations between end-systolic pres... more A hemodynamic-radionuclide study was performed to compare the relations between end-systolic pressure and volume in the left and right ventricles in 10 patients with biventricular failure, and to correlate the end-systolic pressure-volume slope with baseline variables of systolic function. During nitroprusside or nitroglycerin infusion, or a combination of both, linear relations were found between end-systolic pressure and volume for both ventricles. In 9 of 10 patients, the end-systolic pressure-volume slope was greater for the left ventricle (mean +/- SD 1.12 +/- 0.36 mm Hg X m2/ml) than for the right ventricle (0.46 +/- 0.27 mm Hg X m2/ml) (p less than 0.001). In all 10 patients, the volume-axis intercept of the pressure-volume relation was greater for the left ventricle (82 +/- 66 ml/m2) than for the right ventricle (2 +/- 30 ml/m2) (p less than 0.005). Right ventricular pressure-volume slope correlated weakly with baseline right ventricular ejection fraction (r = 0.69, p less than 0.05), strongly with the baseline right ventricular end-systolic pressure-volume ratio (r = 0.89) and inversely with baseline right ventricular end-systolic volume (r = -0.86). In conclusion, 1) in patients with severe biventricular failure, changes in systolic pressure influence end-systolic volume more strongly in the right than in the left ventricle. 2) For the right ventricle, the slope of the end-systolic pressure-volume relation is directly related to rest indexes of systolic function. 3) The greater the end-systolic volume at rest, the greater the predicted improvement in right ventricular emptying for any vasodilator-induced reduction in pulmonary artery end-systolic pressure.
Journal of the American College of Cardiology, 1983
The long-term cardiac prognosis of 24 clinically healthy men with complete right bundle branch bl... more The long-term cardiac prognosis of 24 clinically healthy men with complete right bundle branch block, identified from the 1,142 men constituting the population of the Baltimore Longitudinal Study on Aging, was assessed over a follow-up period averaging 8.4 years. When compared with a control group matched for age at which right bundle branch block appeared (mean +/- standard deviation 64.0 +/- 13.5 years), men with right bundle branch block showed no difference in the prevalence of antecedent coronary risk factors or obstructive lung disease. The incidence of angina pectoris, myocardial infarction, valvular heart disease, cardiomegaly, congestive heart failure, advanced heart block or cardiac death in these men did not differ from that of the control group over the observation period. Furthermore, at the latest follow-up study, maximal aerobic exercise tolerance and chronotropic response to maximal exercise were not impaired in men with right bundle branch block relative to control men (9.1 +/- 2.2 versus 7.3 +/- 3.0 minutes and 150.3 +/- 23.5 versus 147.7 +/- 20.7 beats/minute, respectively). However, axis deviation leftward of -30 degrees was present in 46% of men with right bundle branch block but in only 15% of control subjects at latest follow-up (probability [p] less than 0.01). Although the PR interval lengthened by 40 ms or more developed in only 6% of control subjects over the observation period, such prolongation occurred in 29% of men with right bundle branch block (p less than 0.05). These results support the concept that right bundle branch block in these asymptomatic men is a manifestation of a primary abnormality of the cardiac conduction system but has no demonstrable adverse effect on long-term cardiac morbidity or mortality.
The relative contribution of inotropic and vasodilator effect to amrinone-induced hemodynamic imp... more The relative contribution of inotropic and vasodilator effect to amrinone-induced hemodynamic improvement in congestive heart failure (CHF) is unknown. In 9 patients with CHF, the effects of amrinone and nitroprusside on hemodynamic and radionuclide measurements were compared to determine whether reduced afterload accounts for the amrinone-induced decrease in left ventricular end-systolic volume. In each patient, the end-systolic pressure-volume relation was derived using nitroprusside. After terminating nitroprusside treatment, intravenous amrinone (3 mg/kg) caused end-systolic volume to decrease from 148 +/- 32 ml/m2 (mean +/- standard deviation) to 133 +/- 32 ml/m2 (p less than 0.05), causing an increase in cardiac index from 1.9 +/- 0.8 to 2.7 +/- 0.8 liters/min/m2 (p less than 0.001). Arterial end-systolic pressure decreased in all patients during amrinone administration, from 96 +/- 22 to 84 +/- 19 mm Hg (p less than 0.005), as did systemic vascular resistance. Nitroprusside doses needed to match the decrease in LV end-systolic volume induced by amrinone caused significantly greater decreases in arterial end-systolic pressure than did amrinone (p less than 0.01). The amrinone-induced decrease in end-systolic volume exceeded that predicted for a pure vasodilator based on arterial end-systolic pressure and the nitroprusside-derived pressure-volume relation in 6 patients. In 3 patients, the decrease in end-systolic volume did not exceed that expected for a pure vasodilator. In conclusion, after amrinone treatment, afterload reduction occurs in all patients with severe CHF and is the sole effect in some.(ABSTRACT TRUNCATED AT 250 WORDS)
Although vasodilators improve cardiac output in severe left ventricular (LV) failure, the degree ... more Although vasodilators improve cardiac output in severe left ventricular (LV) failure, the degree to which reduction in mitral regurgitation (MR) contributes to this response is unknown. In the present study, nitroprusside-induced changes in forward cardiac output were compared with simultaneous radionuclide LV output in 14 patients with severe LV systolic dysfunction in the absence of known primary valvular disease. Regurgitant output was estimated as LV output minus forward output and regurgitant fraction was calculated as regurgitant output/ LV output. At rest, LV ejection fraction averaged 0.16 4-0.04 (mean 4-standard deviation). Patients were classified into 2 groups based on regurgitant fraction at rest. Group I (n = 5) had little or no detectable valvular regurgitation, with regurgitant fraction less than 0.10; group II (n = 9) had evidence of MR with regurgitant fraction greater than 0.30.
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