Therapeutics in Congestive Heart Failure: From Hemodynamics to Neurohormones. In: Singal PK, Dixon IMC, Kirshenbaum LA, Dhalla NS, editors. Cardiac Remodeling and Failure. Boston: Springer US; 2003. pp. 17-34. [DOI: 10.1007/978-1-4419-9262-8_2]

Vasopressin antagonists in the management of heart failure

Vasopressin antagonists have been studied in a variety of clinical settings, including patients with acute and chronic heart failure. The clinical trials published to date have sought to describe the clinical and physiologic effects of these agents in an effort to prove clinical efficacy and safety. A variety of agents with varying effects on V2 and V1a vasopressin receptor subtype have been studied. They have been shown to reduce bodyweight and improve serum sodium without worsening renal function. They may also decrease the need for loop diuretic use and may be particularly useful in patients with hyponatremia in the setting of volume overload. Further studies are underway that are powered to assess for morbidity and mortality benefits. The beneficial effects have been well documented but, until outcomes are understood more fully, the use of these agents should be limited to currently approved indications. In the USA, this includes only the treatment of euvolemic hyponatremia.

Interactions between the sympathetic nervous system and the RAAS in heart failure

Therapy for heart failure caused by left ventricular systolic dysfunction is based on interference with maladaptive activation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS). Agents that block beta-adrenergic receptors, decrease angiotensin-II formation, and antagonize the effects of angiotensin II and aldosterone have been shown to improve morbidity and mortality in this syndrome. Therefore, from a theoretical point of view, it would be desirable to actually diminish the degree of overactivity of these two homeostatic systems. There are compelling physiologic arguments and much experimental data to suggest that beta-adrenergic blockade may diminish activity of the RAAS. Conversely, angiotensin-converting enzyme inhibitors, angiotensin-II antagonists, and aldosterone antagonists may diminish activity of the SNS. Some clinical trials data may be interpreted in a fashion that suggests that part of the benefit of interfering with each system may relate to diminishing activity of the other. If true, combined therapy may lead to a virtuous cycle in which diminishing the adverse effects of each individual system is combined with reduced activity of the other. Such a cycle may be one factor underlying the impressive clinical results of recent neurohormonally based therapeutic trials and reinforces the need to look beyond acute hemodynamic effects of therapeutic agents when assessing their long-term impact in heart failure.