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Heart rate variability in idiopathic dilated cardiomyopathy: relation to disease severity and prognosis
G Yi1, J H Goldman, P J Keeling
1Department of Cardiological Sciences, St George's Hospital Medical School, London.
Insights
Heart rate variability (HRV) is reduced in patients with idiopathic dilated cardiomyopathy (DCM), indicating disease severity. Reduced HRV serves as an early, non-invasive marker for DCM progression.
Area of Science:
- Cardiology
- Non-invasive diagnostics
Background:
- Idiopathic dilated cardiomyopathy (DCM) is a significant cause of heart failure.
- Early detection of DCM progression is crucial for patient management.
- Heart rate variability (HRV) reflects autonomic nervous system function and has shown potential as a prognostic marker.
Purpose of the Study:
- To evaluate the clinical significance of heart rate variability (HRV) in patients diagnosed with idiopathic dilated cardiomyopathy (DCM).
- To determine if HRV can serve as an early indicator of disease progression in DCM patients.
Main Methods:
- 24-hour time-domain analysis of heart rate variability (HRV) was conducted.
- Participants included 64 patients with DCM, 19 relatives with potential early DCM, and 33 healthy controls.
- Clinical data, including functional class and left ventricular parameters, were collected.
Main Results:
- Patients with DCM exhibited significantly reduced HRV compared to healthy controls.
- Reduced HRV was associated with increased disease severity, including NYHA functional class and reduced ejection fraction.
- A standard deviation of normal to normal RR intervals (SDNN) below 50 ms independently predicted a higher risk of progressive heart failure and lower survival rates.
Conclusions:
- Heart rate variability (HRV) is demonstrably reduced in patients with idiopathic dilated cardiomyopathy (DCM).
- HRV measurements correlate with DCM disease severity and progression.
- HRV is a valuable, non-invasive tool for early detection of DCM deterioration and risk stratification.
Objective:
To assess the clinical importance of heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (DCM).
Patients And Methods:
Time domain analysis of 24 hour HRV was performed in 64 patients with DCM, 19 of their relatives with left ventricular enlargement (possible early DCM), and 33 healthy control subjects.
Results:
Measures of HRV were reduced in patients with DCM compared with controls (P < 0.05). HRV parameters were similar in relatives and controls. Measures of HRV were lower in DCM patients in whom progressive heart failure developed (n = 28) than in those who remained clinically stable (n = 36) during a follow up of 24 (20) months (P = 0.0001). Reduced HRV was associated with NYHA functional class, left ventricular end diastolic dimension, reduced left ventricular ejection fraction, and peak exercise oxygen consumption (P < 0.05) in all patients. DCM patients with standard deviation of normal to normal RR intervals calculated over the 24 hour period (SDNN) < 50 ms had a significantly lower survival rate free of progressive heart failure than those with SDNN > 50 ms (P = 0.0002, at 12 months; P = 0.0001, during overall follow up). Stepwise multiple regression analysis showed that SDNN < 50 ms identified, independently of other clinical variables, patients who were at increased risk of developing progressive heart failure (P = 0.0004).
Conclusions:
HRV is reduced in patients with DCM and related to disease severity. HRV is clinically useful as an early non-invasive marker of DCM deterioration.