<qa>  What is thought to contribute to the pathophysiology of congestive heart failure?Overactivity of the sympathetic nervous system is thought to contribute to the pathophysiology of congestive heart failure CHF. Blockade of the sympathetic nervous system with β-adrenergic inhibitors could be expected to ameliorate these detrimental effects in a manner analogous to the effects of the angiotensin converting enzyme inhibitors on the overactive renin-angiotensin system. 