The Terminal Part of the QT Interval (T peak to T end): A Predictor of Mortality after Acute Myocardial Infarction

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Abstract
Background: The terminal part of the QT interval (T peak to T end; Tp‐e)—an index for dispersion of cardiac repolarization—is often prolonged in patients experiencing malignant ventricular arrhythmias after acute myocardial infarction (AMI). We wanted to explore whether high Tp‐e might predict mortality or fatal arrhythmia post‐AMI.Methods: Tp‐e was measured prospectively in 1359/1384 (98.2%) consecutive patients with ST elevation (n = 525) or non‐ST elevation (n = 859) myocardial infarction (STEMI or NSTEMI) admitted for coronary angiography.Results: Tp‐e was significantly correlated with age, heart rate (HR), heart failure, LVEF, creatinine, three‐vessel disease, previous AMI and QRS and QT duration. During a mean follow‐up of 1.3 years (range 0.4–2.3),109 patients (7.9%) died; 25, 45, and 39 from cardiac arrhythmia, nonarrhythmic cardiac causes and other causes, respectively. Long Tp‐e was strongly associated with increased risk of death, and Tp‐e remained a significant predictor of death in multivariable Cox analyses (RR 1.5, 95% CI[1.3–1.7]). HR‐corrected Tp‐e (cTp‐e) was the strongest predictor of death (RR 1.6 [1.4–1.9]). Tp‐e and cTp‐e were particularly strong predictors of fatal cardiac arrhythmia (RR 1.6 [1.2–2.1] and RR 1.8 [1.4–2.4]). Findings were similar in STEMI and NSTEMI. When comparing two methods for measuring Tp‐e, one including the tail of the T wave and one not, the former had markedly higher predictive power (P < 0.001).Conclusion: Tp‐e, and in particular cTp‐e, were strong predictors of mortality during the first year post‐AMI, and should be further evaluated as prognostic factors additional to established post‐AMI risk factors.

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