Prognostic Impact of Ventricular Arrhythmia Timing in Acute Coronary Syndromes Treated with Percutaneous Coronary Intervention: A Systematic Review and Network Meta-Analysis

Background: Ventricular arrhythmias (VA) often complicate acute coronary syndromes (ACS). The prognostic impact of VA timing relative to percutaneous coronary intervention (PCI) remains unclear. Objective: To assess the prognostic significance of VA based on their timing of occurrence in relation to PCI. Methods: Systematic review and meta-analysis of observational studies reporting all-cause mortality with and without VA (sustained or hemodynamically unstable VT/VF) in ACS patients undergoing PCI. The endpoints analyzed were short-term (30 days/in-hospital) and long-term (1 year) mortality. A network meta-analysis comparing VA-before PCI, VA-during PCI, and VA-after PCI with the group not experiencing VA as a reference was conducted. Results: Twelve studies comprising 49,963 patients were included, of whom 3,475 (7.0%) experienced VA. VA was associated with increased short- (OR 5.04, 95%CI 3.78-6.72) and long-term mortality (OR 2.92, 95%CI 2.20-3.86). In patients alive at discharge/30 days, subsequent long-term mortality risk did not differ between those with and without VA (OR 0.97, 95%CI 0.62-1.52). The network meta-analysis showed that all VA timings are associated with a significantly higher risk compared with the group not experiencing VA. Sensitivity analysis found that VA-after is associated with higher short-term mortality than earlier VA (OR 3.37, 95%CI 1.46-7.82). Conclusions: VA substantially increase the risk of death in patients with ACS undergoing PCI. Mortality risk emerges to be associated with the timing of VA occurrence, with VA-after PCI associated with the highest risk. These findings highlight the prognostic relevance of arrhythmic events across the entire peri-procedural window, underscoring the need for refined risk stratification.