Aims: Ventricular tachycardia (VT) induction at electrophysiological (EP) study early after ST elevation myocardial infarction (STEMI) has been a predictor of spontaneous ventricular arrhythmia. Reperfusion therapy for STEMI may have resulted in altered VT character. We attempted to determine differences in VT cycle length (CL) and VT recurrence rates, in patients who received early and late reperfusion treatment for STEMI.
Methods and results: Of 180 consecutive patients with left ventricular ejection fraction < 40%, 77 patients had positive EP studies. Forty-nine patients receiving early reperfusion treatment (group 1, n = 49) were compared with 28 patients who received late reperfusion (group 2; n = 28). Seventy-five patients had defibrillators implanted for primary prevention of sudden death. Patients were followed for up to 6 years to assess long-term rates of spontaneous ventricular tachyarrhythmia. Patients who received early reperfusion demonstrated shorter CL inducible VT (231 ± 43 ms vs. 252 ± 56 ms; P = 0.016). They also had fewer spontaneous arrhythmias (adjusted hazard ratio of 2.94, 95% confidence interval: 1.07-8.13; P = 0.03) with shorter CL spontaneous VT (266 ± 54 ms vs. 320 ± 80 ms; P = 0.02) at 53 ± 33 months. Ventricular tachycardia CL was the only independent predictor of spontaneous arrhythmia or sudden cardiac death (1.22, 1.07-1.47; P = 0.016).
Conclusions: Patients receiving early reperfusion for STEMI had faster inducible and spontaneous VT and fewer spontaneous recurrences. This may be due to changes in the myocardial substrate as a result of early coronary artery reperfusion.
Keywords: Acute myocardial infarction; Electrophysiology; ST elevation myocardial infarction; Ventricular tachycardia.
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