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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