Ventricular arrhythmia burst is an independent indicator of larger infarct size even in optimal reperfusion in STEMI

•Infarct size was larger in patients with VA burst, in spite of TIMI 3, MBG 3, and ST-resolution.•VA burst is an additional marker in defining suboptimal reperfusion and larger infarct size.•Understanding the pathophysiology of VA burst could aid treatment to reduce infarct size.

ObjectiveWe hypothesized that ventricular arrhythmia (VA) bursts during reperfusion phase are a marker of larger infarct size despite optimal epicardial and microvascular perfusion.Methods126 STEMI patients were studied with 24 h continuous, 12-lead Holter monitoring. Myocardial blush grade (MBG) was determined and VA bursts were identified against subject-specific background VA rates in core laboratories. Delayed-enhancement cardiovascular magnetic resonance imaging was used to determine infarct size.ResultsIn the group with MBG 3 no significant differences were found for baseline characteristics between burst versus no burst (102 vs. 24). In those with optimal epicardial and microvascular reperfusion (TIMI 3, stable ST-recovery, and MBG 3), VA burst was associated with larger infarct size (N = 102/126; median 11.0 vs. 5.1%; p = 0.004).ConclusionIn the event of MBG 3, VA bursts were associated with significantly larger infarct size even if optimal epicardial and microvascular reperfusion was present.

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