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

Objective: We hypothesized that ventricular arrhythmia (VA) bursts during reperfusion phase are a marker of larger infarct size despite optimal epicardial and microvascular perfusion.

Methods: 126 STEMI patients were studied with 24h 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.

Results: In 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).

Conclusion: In the event of MBG 3, VA bursts were associated with significantly larger infarct size even if optimal epicardial and microvascular reperfusion was present.