Modified moving average analysis of T-wave alternans correlated strongly with input values (r2 = 0.9999) and tracked vulnerability to ventricular fibrillation with 100% sensitivity and specificity.
The modified moving average method accurately measures T-wave alternans in the presence of artifacts and noise, providing a robust estimate of risk for ventricular fibrillation.
Effect estimate: r(2) = 0.9999
T-wave alternans is a marker of cardiac electrical instability with the potential for arrhythmia risk stratification. The modified moving average method was developed to measure alternans in settings with artifacts, noise, and nonstationary data. Algorithms were developed and performance characteristics were validated with simulated electrocardiograms (ECGs). Experimental laboratory ECGs with dynamically changing alternans values were analyzed. Alternans values estimated by modified moving average analysis correlated strongly with input alternans values (r(2) = 0.9999). Rapidly changing alternans levels and phase reversals did not perturb the measurement. When heart rate was increased from 60 to 180 beats/min, with T-wave alternans apex moving from 237 to 103 ms after the R wave, the measured alternans peak varied <5% from input value. Simulated 50- to 1,000-microV motion artifact spikes typical of treadmill ECGs produced inaccuracies <2%. Alternans values in experimental laboratory study using standard electrodes tracked vulnerability to myocardial ischemia-induced ventricular fibrillation with 100% sensitivity and specificity at a cut point of 0.75 mV. Modified moving average analysis is a robust method that precisely measures T-wave alternans in settings with artifacts, noise, and nonstationary data typical of clinical ECGs and yields an accurate estimate of risk for ventricular fibrillation.
Nearing et al. (Fri,) conducted a other in Ventricular fibrillation. Modified moving average analysis of T-wave alternans vs. Input alternans values was evaluated on Correlation with input alternans values and prediction of ventricular fibrillation (r(2) = 0.9999). Modified moving average analysis of T-wave alternans correlated strongly with input values (r2 = 0.9999) and tracked vulnerability to ventricular fibrillation with 100% sensitivity and specificity.