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Heart rate variability in idiopathic dilated cardiomyopathy: characteristics and prognostic value
L Fauchier1, D Babuty, P Cosnay
1Cardiology B and Electrophysiology Department, Hospital Trousseau, Tours, France. lfau@med.univ.tours.fr
Insights
Reduced heart rate variability (HRV) in idiopathic dilated cardiomyopathy (IDC) patients is linked to left ventricular dysfunction. This HRV analysis identifies patients at higher risk for cardiac death or heart transplantation.
Area of Science:
- Cardiology
- Heart Failure Research
- Autonomic Nervous System Function
Background:
- Heart rate variability (HRV) is a known predictor of arrhythmic events post-myocardial infarction.
- The specific characteristics and prognostic implications of HRV in idiopathic dilated cardiomyopathy (IDC) remain incompletely understood.
Purpose of the Study:
- To evaluate heart rate variability (HRV) in patients diagnosed with idiopathic dilated cardiomyopathy (IDC).
- To assess the correlation between HRV and hemodynamic variables, as well as ventricular arrhythmias in IDC patients.
- To determine the prognostic significance of HRV in predicting outcomes for IDC patients.
Main Methods:
- Time-domain analysis of HRV was conducted on 24-hour electrocardiographic (ECG) recordings.
- The study included 93 patients with IDC and 63 healthy control subjects.
- Comparisons were made between patient groups and controls, and correlations with clinical and hemodynamic parameters were analyzed.
Main Results:
- Patients with IDC exhibited significantly lower HRV compared to controls, irrespective of heart failure status.
- HRV demonstrated a significant correlation with left ventricular shortening fraction and peak oxygen uptake.
- Reduced HRV was associated with an increased risk of cardiac death or heart transplantation during follow-up.
- Multivariate analysis identified increased left ventricular end-diastolic diameter, reduced HRV (SDNN), and elevated pulmonary capillary wedge pressure as predictors of cardiac events.
Conclusions:
- Decreased HRV in IDC is primarily associated with left ventricular dysfunction, not ventricular arrhythmias.
- HRV analysis serves as a valuable tool for identifying IDC patients at elevated risk for adverse cardiac outcomes, including death or transplantation.
Objectives:
This study was designed to evaluate heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (IDC), to determine its correlation with hemodynamic variables and ventricular arrhythmias and to evaluate its prognostic value in IDC.
Background:
Previous studies have shown that HRV could predict arrhythmic events in patients after infarction, but the characteristics of HRV in IDC have not been fully established.
Methods:
Time domain analysis of HRV on 24-h electrocardiographic (ECG) recording was performed in 93 patients with IDC, and results were compared with those in 63 control subjects.
Results:
Patients with IDC, even those without congestive heart failure, had significantly lower values for HRV than those of control subjects. HRV was related to left ventricular shortening fraction (R = 0.5, p = 0.0001) and to peak oxygen uptake (R = 0.53, p = 0.01). HRV was not different in patients with runs of ventricular tachycardia or in patients with late potentials on the signal-averaged ECG. During a mean follow-up period (+/-SD) of 49.5 +/- 35.6 months, patients with reduced HRV had an increased risk of cardiac death or heart transplantation (p = 0.006). On multivariate analysis, cardiac events were predicted by increased left ventricular end-diastolic diameter (p = 0.0001), reduced standard deviation of all normal to normal RR intervals (p = 0.02) and increased pulmonary capillary wedge pressure (p = 0.04).
Conclusions:
Decreased HRV in patients with IDC is related to left ventricular dysfunction and not to ventricular arrhythmias. Analysis of HRV can identify patients with IDC who have an increased risk of cardiac death or heart transplantation.