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Keywords:

  • angioplasty;
  • electrocardiography;
  • myocardial infarction;
  • ventricular tachycardia;
  • T-wave alternans

TWA and Arrhythmias in STEMI After PCI

 Introduction

Successful reperfusion with primary percutaneous coronary intervention (PCI) can paradoxically elicit temporary vulnerability to ventricular arrhythmia. We examined whether T-wave alternans (TWA) level is correlated with nonsustained ventricular tachycardia (NSVT) incidence in association with PCI in patients with acute ST-segment elevation myocardial infarction (STEMI).

Methods and Results

We analyzed continuous 24-hour ambulatory electrocardiograms in 48 STEMI patients during and after successful primary PCI, achieving Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow. TWA was measured using modified moving average method. Maximum TWA was elevated in patients with (N = 22) compared to without (N = 26) NSVT (75.1 ± 6.3 vs 49.9 ± 3.6 μV, P < 0.005) during the 22-hour monitoring period. TWA ≥ 60μV predicted NSVT with sensitivity of 77%; specificity, 73%; positive predictive value, 71%; and negative predictive value, 79%. Area under receiver operator characteristic curve (AUC) was 0.87 for maximum TWA in predicting NSVT. By comparison, ST-segment levels did not differ in patients with versus without NSVT and were not predictive (AUC = 0.52). TWA was elevated prior to PCI and remained elevated at 30 minutes after balloon inflation despite restoration of TIMI grade 3 flow in all patients, declining by 22 hours (P < 0.05). Maximum ST-segment levels decreased from before PCI to 30 minutes after balloon inflation. TWA is regionally specific, with higher values prior to PCI in precordial lead V5 than in V1 for left coronary lesions.

Conclusions

TWA may be useful in identifying individuals at heightened risk for arrhythmia in association with primary PCI and can potentially signal time-dependent changes in arrhythmia vulnerability.