To evaluate the clinical importance of heart rate variability (
HRV) in patients with dilated cardiomyopathy (DCM), time domain
and frequency domain analysis of 24 hour HRV was performed in 40
patients with DCM (group A): [29(72.5%) patients with ischemic
cardiomyopathy and11(27.5%)patients with idiopathic cardiomyopathy;
26(65%)males and 14(35%) females with a mean age 44+12
years] and 20 normal healthy controls (group B): [12(60%)males and 8
(40%)females with a mean age 43+11 years]. All measurements of
HRV were significantly reduced in patients with DCM compared with
the control group (P<0.01) . 29/40 ( 72.5%) patients completed their
follow up for 6±2 months ; 11 (38%) developed progressive heart
failure (HF) defined by a deterioration in NYHA functional class that
was refractory to maximal medical therapy. This group included 4
cardiac deaths during their follow up, while the remaining 18 (62%)
remained clinically stable. Measures of HRV were further reduced in
patients who developed progressive HF during follow up than in those
who remained clinically stable. The SDNNI measure of the time
domain HRV was correlated with NYHA functional class, enddiastolic
dimension (EDD) and reduced left ventricular ejection
fraction (EF). HRV was reduced in patients with DCM and related to
disease severity. HRV is clinically useful as an early noninvasive
marker of DCM deterioration. |
