ABSTRACT
Congestive heart failure is characterized by hemodynamic and non-hemodynamic abnormalities, the latter including an activation of the sympathetic influences to the heart and peripheral circulation coupled with an impairment of baroreceptor control of autonomic function. Evidence has been provided that both these alterations are hallmark features of the disease with a specific relevance for the disease progression as well as for the development of life-threatening cardiac arrhythmias. In addition, a number of studies have documented in heart failure the adverse prognostic role of the sympathetic and baroreflex alterations, which both are regarded as major independent determinants of cardiovascular morbidity and mortality. This represents the pathophysiological and clinical background for the use of carotid baroreceptor activation therapy in the treatment of congestive heart failure. Promising data collected in experimental animal models of heart failure have supported the recent performance of pilot small-scale clinical studies, aimed at providing initial information in this area. The results of these studies demonstrated the clinical safety and efficacy of the intervention which has been tested in large-scale clinical studies. The present paper will critically review the background and main results of the published studies designed at defining the clinical impact of baroreflex activation therapy in congestive heart failure patients. Emphasis will be given to the strengths and limitations of such studies, which represent the background for the ongoing clinical trials testing the long-term effects of the device in heart failure patients.
Subject(s)
Baroreflex/physiology , Electric Stimulation Therapy , Heart Failure/physiopathology , Heart Failure/therapy , Hypertension/physiopathology , Hypertension/therapy , Animals , Arrhythmias, Cardiac/physiopathology , Disease Models, Animal , Dogs , Heart/physiopathology , Heart Failure/mortality , Hemodynamics/physiology , Humans , Hypertension/mortality , Pressoreceptors/physiopathology , Randomized Controlled Trials as Topic , Survival Rate , Sympathetic Nervous System/physiopathologyABSTRACT
Scanty information is available on the effects of combination drug treatment based on an ACE inhibitor and a calcium channel blocker on the neurometabolic alterations characterizing obesity-related hypertension (OHT). After 2-week run-in with enalapril (20 mg), 36 OHTs were randomized according to a double-blind crossover design to a combination therapy with either lercanidipine 10 mg (L) or felodipine extended release 5 mg (F), each lasting 8 weeks. Measurements included clinic and ambulatory blood pressure (BP) and heart rate, homeostasis model assessment index, plasma norepinephrine, and muscle sympathetic nerve activity. Patients with uncontrolled BP were then uptitrated to 20 mg/d (L) and 10 mg/d (F) combined with enalapril 20 mg, respectively, for further 8 weeks. For similar BP reductions, enalapril-lercanidipine (EL) caused norepinephrine and MSNA increases significantly less pronounced than those seen with enalapril-felodipine, the lesser sympathoexcitation observed with EL being coupled with a significant improvement in homeostasis model assessment index. This was the case also when L and F were uptitrated in the combination. In OHT, at variance from enalapril-felodipine, EL combination is almost entirely devoid of any major sympathoexcitatory effect and is associated with an improvement in insulin sensitivity.
