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[Temporal and spectral analysis of heart rate variability in primary dilate cardiomyopathy: evaluation by case
L Fauchier1, D Babuty, M L Autret
1Service de cardiologie B, UMR CNRS 6542, hôpital Trousseau, Tours.
Insights
Heart rate variability (HRV) is significantly lower in dilated cardiomyopathy (DCM) patients, reflecting left ventricular dysfunction. Reduced HRV indicates a higher risk of cardiovascular death and heart transplantation in DCM patients.
Area of Science:
- Cardiology
- Physiology
- Biomedical Engineering
Background:
- Dilated cardiomyopathy (DCM) is a significant cause of heart failure.
- Heart rate variability (HRV) analysis offers insights into autonomic nervous system function.
- Assessing HRV in DCM patients can aid in risk stratification.
Purpose of the Study:
- To investigate temporal and spectral heart rate variability (HRV) in patients with primary dilated cardiomyopathy (DCM).
- To compare HRV between DCM patients and healthy controls.
- To determine the relationship between HRV and clinical parameters, ventricular dysfunction, and prognosis in DCM.
Main Methods:
- 24-hour ambulatory ECG monitoring for HRV analysis.
- Left ventriculography to assess left ventricular ejection fraction and dimensions.
- Comparison of HRV parameters between 89 DCM patients and 60 control subjects.
- Correlation analysis between HRV and clinical/hemodynamic parameters.
Main Results:
- HRV was significantly lower in DCM patients compared to controls, irrespective of clinical heart failure signs.
- Global HRV correlated with left ventricular fractional shortening and peak oxygen consumption.
- Decreased HRV predicted a higher risk of cardiovascular death and cardiac transplantation during follow-up.
- HRV was independent of ventricular arrhythmias and late potentials.
Conclusions:
- HRV is reduced in DCM, primarily linked to left ventricular dysfunction.
- HRV analysis can identify DCM patients at high risk for adverse cardiovascular events.
- HRV serves as a valuable prognostic marker in dilated cardiomyopathy.
Abstract:
Temporal and spectral analysis of heart rate variability over 24 hours (HRV) was undertaken in 89 patients with primary dilated cardiomyopathy (DCM) confirmed by left ventriculography with normal coronary angiography and compared with 60 control subjects. The left ventricular ejection fraction was 35 +/- 12% in the DCM patients (71 men and 18 women: age 51 +/- 11 years). Clinical signs of cardiac failure were observed in 66% of patients, requiring medication in 62% of patients (diuretics: 47%, digitalis: 45% and ACE inhibitors: 33%). The HRV was significantly lower in the DCM patients than in the control group, even in the absence of clinical signs of cardiac failure. The global HRV was correlated to left ventricular fractional shortening (r = 0.5, p < 0.001) and peak oxygen consumption on exercise (r = 0.56, p < 0.01), but was independent of the degree of left ventricular dilatation, pulmonary capillary pressure and cardiac index. It was not significantly different in cases of sustained or non-sustained ventricular tachycardia on Holter ECG or in cases with late ventricular potentials on signal averaging of the surface ECG. During follow-up of 51 +/- 35 months, patients with decreased HRV on the global indices and those reflecting sympathetic activity had a much higher risk of cardiovascular death and of cardiac transplantation (p < 0.01). The authors conclude that HRV is decreased in DCM. This is mainly related to the degree of left ventricular dysfunction and is independent of the ventricular arrhythmogenic substrate. The HRV may also identify subgroups of patients with DCM at high risk of cardiovascular death or of haemodynamic decompensation requiring cardiac transplantation.