Heart rate variability in dilated cardiomyopathy - usefulness, prognostic value

1 ”Prof. Dr. C.C. Iliescu” Emergency Institute for Cardiovascular Diseases, Bucharest 2 “Carol Davila” University of Medicine and Pharmacy, Bucharest Contact address: Dr. Costel Matei, ”Prof. Dr. C.C. Iliescu” Emergency Institute for Cardiovascular Diseases, Cardiology Clinic, IInd Unit, 258, Fundeni Road, 022328 Bucharest, Romania. E-mail: [email protected] Abstract: Heart rate variability, expression of balance between sympathetic and parasympathetic tonus, is frequently reduced in patients with heart failure due to sympathetic hyperactivity. Its use in predicting mortality risk in patients with heart failure has been studied previously, proved to be a useful non/invasive method for risk stratifi cation. Aim – To evaluate the usefulness and prognostic value of heart rate variability (HRV) parameters in patients with dilated cardiomyopathy (DCM). Methods: Fift y-one patients (76.5% men) with dilated cardiomyopathy of various etiologies were included in the study. Time-domain heart rate variability parameters from the 24h ECG recordings were analyzed. Patients were followed clinically, ECG, echocardiography for a mean of 47.4 months (range 6-90 months); 22 deaths were observed during study period. Statistical analysis was performed with MedCalc 12.3.0.0 (Medcalc Soft ware BVBA, Belgium). Results – 24h ECG recordings was indicated in 71% of patients as a class I indication and in 29% of patients and class IIb indication. Th ere were no signifi cant diff erences between HRV parameters between diff erent DCM etiologies. Patients were divided in tertiles according to the HRV parameters. Death risk shows, without reaching statistical signifi cance, a progressive decrease with rMSSD increase, for all other parameters U-shape curves were observed in the study group tertiles. Kaplan-Meier survival curves showed no survival diff erence between tertiles or between low or normal HRV, except rMSSD where survival was better in patients with reduced HRV. Conclusions – Our data are useful primarily to a better parameters defi nition of values considered to be discriminatory for patients with “low variability”. Th ere were no statistically signifi cant diff erences in HRV parameters between diff erent causes of DCM. Statistical analysis failed to show a signifi cant survival diff erence according to HRV parameters. Probably it is necessary to consider these parameters together with other factors that infl uence the evolution of patients with DCM and heart failure.