Autonomic nervous system activity imbalance in cardiomyopathic hamster

There is strong evidence that autonomic imbalance plays an important role i n progression of heart failure. Analysis of heart rate variability (HRV) ha s achieved substantial acceptance as a noninvasive method for the assessmen t of autonomic tone. The purpose of this investigation was to study HRV in an experimental model of heart failure using cardiomyopathic (BIO TO.2) ham sters. Animals showed an autonomic imbalance of cardiac control that seems due to attenuation of parasympathetic activity and an enhanced sympathetic tone. The reduction of parasympathetic activity in BIO TO.2 hamsters is sug gested by (a) the reduction of the high-frequency (HF) spectrum, and (b) th e lack of atropine to generate a response. The increased sympathetic activi ty is indicated by (a) the decreased time-domain indexes, (b) the increased LF/HF ratio of the power spectrum, and (c) the alteration of HRV indexes i nduced by propranolol. These results support the notion that in heart failu re, there is a similar autonomic imbalance in both human and hamster and su ggest that the cardiomyopathic hamster is a suitable experimental model for studying the involvement of the autonomic nervous system in the progressio n of heart failure.