To the Editor: The study by Dr Mehta and colleagues1 supports the prognostic importance of ventricular tachycardia or ventricular fibrillation (VT/VF) as an independent predictor of early mortality in patients with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention. Although the authors warned about the limitations of the study, we believe that not considering left ventricular ejection fraction (LVEF) among the predictors of mortality in the multivariable models represents a serious limitation that hinders the interpretation of these data. Left ventricular ejection fraction is a strong predictor of mortality in patients with STEMI,2 and assessing the prognostic value of other covariates without correcting for LVEF may lead to unreliable results. Since there is no adjustment for LVEF, the results of this study may lead to the conclusion that patients who have a preserved LVEF and experience VT/VF, mostly during catheterization, have a 3-fold increase of mortality compared with patients who have a poor LVEF but did not have VT/VF.
Palmerini T, De Servi S, Branzi A. Prognostic Importance of Ventricular Arrhythmia in Patients Treated With Percutaneous Coronary Intervention. JAMA. 2009;302(9):943-945. doi:10.1001/jama.2009.1238