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Predicting Arrhythmia‐Free Survival Using Spectral and Modified‐Moving Average Analyses of T‐Wave Alternans
Author(s) -
COX VERONICA,
PATEL MITUL,
KIM JASON,
LIU TAYLOR,
SIVARAMAN GOWRI,
NARAYAN SANJIV M.
Publication year - 2007
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2007.00675.x
Subject(s) - medicine , t wave alternans , cardiology , sudden cardiac death
Background: T‐wave alternans (TWA) is a promising electrocardiogram (ECG) predictor of sudden cardiac arrest, yet needs specialized recordings for conventional spectral analysis. Modified moving average (MMA) analysis is a new approach that can measure TWA from routine ECGs, thus widening its applicability. However, MMA‐TWA has not been calibrated against spectral TWA nor outcome in high risk patients. We hypothesized that spectral and MMA‐TWA would both predict arrhythmia‐free survival on long‐term prospective follow‐up .Methods and Results: In 41 patients with left ventricular systolic dysfunction (ejection fraction 31 ± 13%), we studied TWA simultaneously using spectral and MMA during pacing (< 110 beats/min). MMA amplified TWA over spectral analyses (13.0 ± 8.28 μV vs 1.96 ± 5.15 μV, P < 0.001). On 542 ± 311 days' follow‐up, from clinic visits, telephonic interviews, and device interrogations, there were 11 deaths or sustained ventricular arrhythmias (‘events’). Positive spectral TWA (≥1.9 μV) identified patients with from those without events (P = 0.02). Receiver‐operating characteristics for MMA‐TWA showed that the cutpoint ≥ 10.75 μV was optimal for the combined endpoint. Kaplan‐Meier analysis using this MMA‐TWA cutpoint trended to predict events (P = 0.06), while MMA combined with spectral TWA identified events (P = 0.01) .Conclusions: MMA amplifies TWA compared to traditional spectral analyses, but both likely reflect similar pathophysiology. Validation in larger populations will enable MMA‐TWA to be widely applied to stratify risk for sudden cardiac arrest.