Chronic dynamic exercise improves a functional abnormality of the G stimulatory protein in cardiomyopathic BIO 53.58 Syrian hamsters

Electrical muscle stimulation for chronic heart failure: an alternative tool for exercise training?

Conventional exercise training has been shown conclusively to improve exercise capacity, quality of life, and even reduce mortality in chronic heart failure. Unfortunately, not all heart failure patients are suitable for conventional exercise programs for various reasons. The exciting new technique of electrical muscle stimulation (EMS) of large groups of muscles has been shown to produce a physiologic response consistent with cardiovascular exercise at mild to moderate intensities by increasing peak oxygen consumption, carbon dioxide production, ventilatory capacity, and heart rate. Additionally, there is improvement in muscle strength. The handful of small studies that exist of home-based EMS training of leg muscles in heart failure show that EMS produces similar benefits to conventional exercise in improving exercise capacity, making EMS an alternative to aerobic exercise training in those that cannot undertake conventional exercise. The improvement seen in leg muscle strength promises also to improve mobility in this sedentary population.

Effects of beta-blockers on neurohormonal activation in patients with congestive heart failure

The effect of beta-adrenoceptor antagonists (beta-blockers) on neurohormonal activation in patients with congestive heart failure has been the subject of study in numerous small clinical trials. Short term therapy with beta-blockers is associated with a variable acute neurohormonal response which may be determined by the pharmacology of the agent under study and the baseline characteristics of the patient population. Long term therapy with beta-blockers devoid of intrinsic sympathomimetic activity (partial agonist activity) is associated with evidence of decreased plasma markers of activation of the sympathetic nervous system, the renin-angiotensin system, and endothelin-1. Beta1-selective and nonselective beta-blockers appear to be associated with evidence of decreased neurohormonal activation, with differential effects on beta-adrenoceptor density. Agents with partial agonist activity appear to differ from pure antagonists, with some studies reporting evidence of increased neurohormonal activation. The mechanisms by which beta-blockers reduce neurohormonal activation and the clinical relevance of changes in adrenergic function to their use in the treatment of heart failure require further investigation.