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Value of heart rate variability parameters for prediction of serious arrhythmic events in patients with malignant
A Filipecki1, M Trusz-Gluza, K Szydlo
1I Clinic of Cardiology, Silesian School of Medicine, Katowice, Poland.
Insights
Heart rate variability (HRV) parameters, specifically standard deviation of RR intervals (SD) and low frequency amplitude (L), predict serious arrhythmic events (SAE) in patients with ventricular tachycardia/fibrillation. Combined HRV and ejection fraction (EF) offer powerful risk prediction.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Statistics
Background:
- Heart rate variability (HRV) is a non-invasive measure of cardiac autonomic function.
- HRV analysis can identify individuals at risk for sudden cardiac death (SCD) and serious arrhythmic events (SAE).
- Predicting SAE in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) is crucial for risk stratification.
Purpose of the Study:
- To evaluate the predictive value of 10 time and frequency domain HRV parameters for SAE in VT/VF patients.
- To assess the combined predictive power of HRV parameters and left ventricular ejection fraction (LVEF) for SAE.
- To identify independent risk factors for SAE in a cohort of non-infarct related VT/VF patients.
Main Methods:
- Analysis of 24-hour ECG recordings to derive 10 HRV parameters.
- Proportional hazard analysis (Cox model) to identify independent predictors of SAE.
- Kaplan-Meier survival analysis to compare event-free survival based on HRV and LVEF thresholds.
Main Results:
- Standard deviation of RR intervals (SD) and low frequency amplitude (L) were identified as independent predictors of SAE (P < 0.05).
- Combined models of SD+LVEF and L+LVEF demonstrated high predictive values for SAE (specificity >95%, positive predictive value >90%).
- Significantly shorter event-free survival was observed in patients with LVEF < 40%, SD < 43 ms, or L < 16 ms (P < 0.001).
Conclusions:
- Specific HRV parameters (SD and L) are valuable predictors of fatal outcomes in VT/VF patients.
- The combination of HRV parameters with LVEF significantly enhances the prediction of serious arrhythmic events.
- HRV analysis, particularly SD and L, offers a powerful tool for risk stratification in patients susceptible to malignant arrhythmias.
Abstract:
Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow-up (6-46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event-free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD+EF and L+EF values are powerful predictors of serious arrhythmic events.