[Dual sequence method for analysis of spontaneous baroreceptor reflex sensitivity in patients with dilated cardiomyopathy].

The analysis of heart rate variability (HRV) and blood pressure variability (BPV) improves the characterization of patients with dilated cardiomyopathy (DCM). In this study we tested the hypothesis that patients with DCM and controls show a different behavior in the baroreflex (BR) regulation. In contrast to other methods, the new dual sequence method (DSM) analyzes the baroreflex sensitivity (BRS) as a response of the heart rate (interbeat interval, IBI) on dual spontaneous fluctuations of blood pressure (BP). The DSM includes the analysis of bradycardiac fluctuations (an increase of BP causes an increase of IBI) and tachycardiac fluctuations (decrease of BP causes a decrease of IBI) to obtain enhanced information about the sympathetic-vagal regulation. DCM patients show a 40-50% lower number of correlated blood pressure-heart rate fluctuations (DCM patients: male 154 +/- 93, female 93 +/- 40 vs. control group: m 245 +/- 112, f 150 +/- 55, p < 0.05). The BRS in DCM patients is significantly lower than in controls (5.2 +/- 1.9 vs. 8.0 +/- 5.4 (ms/mm Hg), p < 0.05). Using the DSM the discriminant function analysis (6 parameters) classifies correctly 84% of DCM patients and the control group. Using the classical sequence method, only 76% were correctly classified. The DSM is a useful method for analyzing the BRS based on the spontaneous BR to obtain an increased classification of patients with DCM. BRS in patients with DCM is significantly reduced and apparently more ineffective.