AUTONOMIC FUNCTIONS IN RESTRICTIVE CARDIOMYOPATHY AND CONSTRICTIVE PERICARDITIS - A COMPARISON

Background This study was undertaken to analyze autonomic functions in restrictive cardiomyopathies. Restrictive cardiomyopathies have clini cal and hemodynamic similarity with chronic constrictive pericarditis. Autonomic dysfunction has been described in the latter. Methods and R esults Autonomic function analysis has not been reported in restrictiv e cardiomyopathy. Six consecutive patients with restrictive cardiomyop athy were included in this study (5 men, 1 woman, mean age 35 +/- 5.4 years). The tests performed were designed to test the sympathetic effe rent pathway that is, by cold hand immersion and loud noise tests, par asympathetic efferent pathway by Valsalva ratio and expiration/inspira tion ratio and the baroreceptor function by testing their sensitivity slope. The results were compared with 20 patients with chronic constri ctive pericarditis and with 10 healthy age- and sex-matched control su bjects previously studied. The rise of systolic blood pressure after c old hand immersion and sudden loud noise was not significantly differe nt compared with control subjects. The expiration/inspiration ratio wa s 1.1 +/- 0.01 compared with 1.57 +/- 0.1 in the control group (p < 0. 01). The Valsalva ratio was significantly lower (1.1 +/- 0.04) compare d with control subjects (1.83 +/- 0.1, p < 0.01). The baroreceptor sen sitivity was not reduced compared with that in control subjects. in co mparison to constrictive pericarditis, sympathetic efferent pathway is preserved in restrictive cordiomyopathy (p < 0.0001). The porasympath etic efferent pathway is borderline abnormal in restrictive cardiomyop athy but not significantly as compared with constrictive pericarditis (p = not significant). The baroreceptor sensitivity slope is normal in patients with restrictive cardiomyopathy as compared with significant depression seen in constrictive pericarditis (p < 0.05). Autonomic fu nctions are better preserved in patients with restrictive cardiomyopat hies compared with chronic constrictive pericarditis. Conclusions Auto nomic dysfunction is localized to parasympathetic efferent pathway. Th is is in comparison to constrictive pericarditis, in which severe auto nomic dysfunction is a universal feature and includes all segments of autonomic nervous system.