Exercise training in patients with severe left ventricular dysfunction. Hemodynamic and metabolic effects.

Abstract

We studied the effects of exercise training in patients with chronic heart failure attributed to left ventricular dysfunction (ejection fraction, 24 ± 10%). Twelve ambulatory patients with stable symptoms underwent 4-6 months of conditioning by exercising 4.1 ± 0.6 hr/wk at a heart rate corresponding to 75% of peak oxygen consumption. Before and after training, patients underwent maximal bicycle exercise testing with direct measurement of central hemodynamic, leg blood flow, and metabolic responses. Exercise training resulted in a decrease in heart rate at rest and submaximal exercise and a 23% increase in peak oxygen consumption from 16.8±3.8 to 20.6±4.7 ml/kg/min (p<0.01). Heart rate, arterial lactate, and respiratory exchange ratio were unchanged at peak exercise after training. Maximal cardiac output tended to increase from 8.9 ± 2.7 to 9.9 ± 3.2 1/min and contributed to improved peak oxygen consumption in some patients, although this change did not reach statistical significance (p= 0.13). Rest and exercise measurements of left ventricular ejection fraction, left ventricular end-diastolic volume, and left ventricular end-systolic volume were unchanged. Right atrial, pulmonary arterial, pulmonary capillary wedge, and systemic arterial pressures were not different after training. Training induced several important peripheral adaptations that contributed to improved exercise performance. At peak exercise, systemic arteriovenous oxygen difference increased from 13.1 ± 1.4 to 14.6 ± 2.3 ml/dl (p <0.05). This increase was associated with an increase in peak-exercise leg blood flow from 2.5 ± 0.7 to 3.0 ± 0.8 I/min (p <0.01) and an increase in leg arteriovenous oxygen difference from 14.5 ± 1.3 to 16.1 ± 1.9 ml/dl (p = 0.07).Arterial and femoral venous lactate levels were markedly reduced during submaximal exercise after training, even though cardiac output and leg blood flow were unchanged at these workloads. Thus, ambulatory patients with chronic heart failure can achieve a significant training eifect from long-term exercise. Peripheral adaptations, including an increase in peak blood flow to the exercising leg, played an important role in improving exercise tolerance. The finding that blood lactate levels at submaximal exercise were reduced without improvements in cardiac output suggests that in patients with chronic heart failure, peripheral metabolic or vascular factors are important in determining the onset of lactate production and may, independent of central hemodynamics, influence exercise tolerance. (Circultion 1988;78:506-515) N mumerous studies during the past 3 decades have established that training in normal subjects leads to an increase in peak exercise oxygen consumption (Vo2). This may be achieved through both improvements in maximal cardiac output and peripheral adaptations.1-8 In normal subjects, these peripheral adaptations include an increase in systemic arteriovenous oxygen (AVo2) difference at peak exercise, which is attributable, in part, to a redistribution of cardiac output to working ...

Exercise capacity and impact of exercise training in patients after a Fontan procedure: A review

“…More specifically, the positive impacts of exercise training in these patients have been correlated to central and peripheral hemodynamics, ventilatory and metabolic responses, and the symptomatic status (63)(64)(65)(66). Enhancements in the sympathetic response, autonomic heart rate control and variability have also been noticed (67).…”

Effects of Cardiopulmonary Exercise Rehabilitation on Left Ventricular Mechanical Efficiency and Ventricular‐Arterial Coupling in Patients With Systolic Heart Failure

“…Theoretically, the most profound effect of exercise training is expected to be on E a , given that several lines of evidence support that exercise training shows its favorable effects on peak VO 2 improvement principally by peripheral adaptations 27. Indeed, it has been shown that exercise training induces significant improvements in arterial compliance,28 peripheral resistance,29 wave reflections,30 skeletal muscle oxidative function,31, 32 and arterial‐venous O 2 difference 33. The modest change in E a in our cohort may be caused by the limited time duration of cardiopulmonary exercise intervention.…”

Rehabilitation in Cardiology and Cardiosurgery

“…[35] в программу кардиореабилитации была включена группа больных ХСН II и III функциональ-ных классов [36].…”