Why the study?
The study evaluated associations of minimum final extrastimulus coupling interval during post-MI electrophysiology study and induced VT site of origin with long-term spontaneous ventricular tachyarrhythmias and survival.
Does the minimum final extrastimulus coupling interval and induced VT morphology during early post-MI EPS predict long-term spontaneous ventricular tachyarrhythmia and survival in patients with LVEF ≤ 40%?
Cohort
Does the minimum final extrastimulus coupling interval and induced VT morphology during early post-MI EPS predict long-term spontaneous ventricular tachyarrhythmia and survival in patients with LVEF ≤ 40%?
Absolute Event Rate: 65.2% vs 23.2%
p-value: p=<0.001
In patients with LVEF ≤ 40% early post-MI, VT induced with shorter coupling intervals (<200 ms) and RBBB morphology during EPS are associated with higher risks of spontaneous ventricular tachyarrhythmia and mortality.
AIMS: This study assessed associations of minimum final extrastimulus coupling interval utilized within electrophysiology study (EPS) after myocardial infarction (MI) and possible site of origin of induced ventricular tachycardia (VT) with long-term occurrence of spontaneous ventricular tachyarrhythmia and long-term survival. METHODS AND RESULTS: This prospective study recruited consecutive patients with left ventricular ejection fraction (LVEF) ≤ 40% who underwent EPS days 3-5 after MI between 2004 and 2017. Positive EPS was defined as sustained monomorphic VT cycle length ≥200 ms for ≥10 s or shorter duration if haemodynamic compromise occurred. Each of the four extrastimuli was shortened by 10 ms at a time, until it failed to capture the ventricle (ventricular refractoriness) or induced ventricular tachyarrhythmia. Outcomes included spontaneous ventricular tachyarrhythmia occurrence and all-cause mortality. Shorter coupling interval length of final extrastimulus that induced VT was associated with higher risk of spontaneous ventricular tachyarrhythmia (P < 0.001). Significantly higher rates of spontaneous ventricular tachyarrhythmia (65.2% vs. 23.2%; P < 0.001) were observed for final coupling interval at EPS <200 ms vs. >200 ms. Right bundle branch block (RBBB) morphology of induced VT, with possible site of origin from the left ventricle, was associated with all-cause mortality [hazard ratio (HR) 3.2, P = 0.044] and a composite of spontaneous ventricular tachyarrhythmia recurrence or mortality (HR 1.8, P = 0.043). CONCLUSION: Ventricular tachycardia induced with shorter coupling intervals was associated with higher risk of spontaneous ventricular tachyarrhythymia on follow-up, indicating that the final extrastimulus coupling interval at EPS early after MI should be determined by ventricular refractoriness. Induced VT with possible origin from left ventricle was associated with increased risk of spontaneous ventricular tachyarrhythmia recurrence or death.
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Kovoor et al. (2023) conducted a cohort in Myocardial infarction with LVEF ≤ 40%. Final extrastimulus coupling interval at EPS <200 ms vs. Final extrastimulus coupling interval at EPS >200 ms was evaluated on Spontaneous ventricular tachyarrhythmia occurrence (p=<0.001).
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