Mehta, R. H. et al. Incidence of and outcomes associated with ventricular tachycardia or fibrillation in patients undergoing primary percutaneous coronary intervention. JAMA 301, 1779–1789 (2009).

Limited information exists on whether ventricular tachycardia or fibrillation (VT/VF) affects the prognosis of patients undergoing percutaneous coronary intervention (PCI). After performing a nonprespecified analysis in the Assessment of Pexelizumab in Acute Myocardial Infarction (APEX-AMI) trial, Rajendra Mehta and colleagues have concluded that VT/VF is associated with increased risk of mortality in patients undergoing PCI.

The investigators analyzed data from 5,745 adults who had presented within 6 h of experiencing symptoms of high-risk ST-segment elevation myocardial infarction (STEMI). VT/VF occurred in 5.7% of patients (n = 329) and was mostly observed within the first 48 h after the onset of symptoms (n = 282). According to Mehta, this finding “precludes the need for monitoring beyond this time point” and, therefore, “has implications for the early discharge of a majority of patients with STEMI who are undergoing primary PCI”.

VT/VF was associated with a higher risk of mortality within 30 days; compared with those who did not experience VT/VF, 30-day mortality was about sixfold more likely in patients who experienced VT/VF before the end of the cardiac catheterization and 11-fold more likely in those who had VT/VF after cardiac catheterization. Cardiovascular events, such as cardiogenic shock, congestive heart failure and recurrent MI, were also more likely to occur in patients who experienced VT/VF, particularly if they experienced it after PCI.

The data indicate that VT/VF is an important prognostic marker in patients undergoing PCI. “The findings need to be validated in future studies,” comments Mehta, “which should also determine the relative prognostic importance of left ventricular ejection fraction, an important variable missing from this study.”