Combined arm-leg ergometry exercise testing.
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Biomedical subjects
Publications and source records attributed to R S Finkelhor.
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Resting measurements of left ventricular systolic function do not reliably predict exercise capacity in patients with cardiac disease. Therefore left ventricular filling shortly after a myocardial infarction was prospectively studied to determine whether it could predict subsequent exercise time. Consecutive patients with an acute infarction underwent Doppler and two-dimensional echocardiography within 36 hours of infarction. The study group was composed of the 26 men who did not have reperfusion, who had an uncomplicated myocardial infarction, and who had undergone symptom-limited stress testing during recovery (modified Bruce protocol, 44 +/- 23 days after myocardial infarction). Systolic function was measured by ejection fraction and a wall motion score. Ventricular filling was assessed by the peak transmitral Doppler velocity in early diastole (E), with atrial systole (A), their ratio (A/E), and the percentage of filling from atrial systole. The only parameter of systolic or diastolic function that correlated with exercise time was E (r = 0.65, p less than 0.001). This relationship was particularly strong for the 16 subjects taking beta blockers at the time of stress testing (r = 0.88, p less than 0.001). Stepwise multivariate regression analysis showed that only E and beta blocker therapy at the time of stress testing contributed to the model predicting recovery exercise time (R2 = 0.55). In summary, E, measured soon after an uncomplicated myocardial infarction, is one factor that predicts exercise capacity during recovery.
Whether exercise-induced increases in left ventricular mass can alter left ventricular diastolic function was evaluated by measuring transmitral flow velocities at rest by Doppler echocardiography in 15 amateur endurance-trained runners and 15 age- and sex-matched sedentary control subjects. Ventricular mass index, end-diastolic volume index and stroke volume index were derived from measurements of M-mode echocardiograms recorded under two-dimensional guidance. All three variables were increased in the runners (p less than 0.01). These findings, plus the lower heart rate at rest (p less than 0.001), were consistent with endurance training. Although the runners had an almost twofold greater myocardial mass index, their peak early diastolic filling velocity and time to peak filling velocity did not differ from those of the sedentary subjects. In runners, the peak filling velocity with atrial systole tended to be lower (p = 0.12), the ratio of peak filling velocity with atrial systole to that of early diastole was less (p less than 0.05) and the percent of stroke volume contributed by atrial systole was less (p less than 0.001). These differences in atrial filling may be related to the lower heart rates at rest in runners. In summary, significant increases in left ventricular mass, when associated with endurance training, do not alter the early diastolic filling of the left ventricle.
Heart failure occurs from both systolic and diastolic dysfunction. To determine whether simple Doppler echocardiographic measures of left ventricular filling could improve upon the ability of systolic function to predict heart failure after infarction, patients with acute myocardial infarction were studied within the first 36 hours by Doppler and two-dimensional echocardiography. Forty-eight patients who did not have heart failure before the Doppler echocardiographic study and who did not have myocardial revascularization, moderate or severe mitral regurgitation, or other complications during recovery were monitored for 6 months or to the onset of heart failure (n = 10). The univariate predictors of heart failure were age (p less than 0.05), anterior infarction (p less than 0.05), early diastolic peak filling velocity (p = 0.05), filling velocity with atrial systole (p less than 0.05), the ratio of these velocities (p less than 0.001), the percentage of filling with atrial systole (p less than 0.001), and the wall motion score index (p less than 0.001). However, the only independent predictors of heart failure by use of multivariant stepwise logistic regression analysis were the wall motion score index (p less than 0.05) and either the ratio of early and late peak filling velocities (p less than 0.001) or the percentage of filling with atrial systole (p less than 0.001). The combined use of a measure of systolic function and measures of the relative contribution of atrial systole to ventricular filling were useful predictors in identifying patients likely to develop subsequent heart failure after myocardial infarction.