Susceptibility of failing myocardium to exercise- induced sympathetic stimulation as a mechanism for progression of chronic heart failure.

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Clinical efficacy of long-term beta-blocker therapy has been demonstrated in patients with chronic heart failure. Thus, exercise-induced sympathetic stimulation and consequent myocardial ischemia and/or tachycardia may exert deleterious metabolic effects on the failing myocardium, promoting progression of heart failure. However, the harmful effects of exercise on failing hearts have not been demonstrated. Diastolic venticular function is known to be sensitive to transient myocardial metabolic insult. In the present study, we investigated the effect of modest exercise on the diastolic left ventricular pressure-volume (P-V) relation was shifted upward during exercise. Moreover, this upward shift effects on failing hearts through beta-adrenergic stimulation.In this study we further studied the recovery process of exercise-examinations were serially performed for 7 days after symptom-limited ade-matched normal subjects. Left ventricular diastolic function was deceleration time (DT) of early diastolic filling wave. Lift ventricular fractional shortening, systolic blood pressure and heart rate were also measured. In patients with heart failure, heart rate, systolic blood pressure, and left ventricular fractional shortening recovered to baseline values 1 hour after cessation of exercise. However, A/E and DT were significantly higher than baseline values for three days after exercise. Significant changes were not observed in any variable in normal subjects. Thus, diastolic function was impaired for at least 3 days after exercise characteristically in patients with chronic heart failure.