QRS width and its impact on inducibility of ventricular arrhythmia at the time of electrophysiology study.

The inducibility of sustained ventricular arrhythmia by programmed electrical stimulation is a well-established marker of an increased risk of ventricular tachyarrhythmia. The purpose of this investigation was to determine whether there was a significant difference in the QRS duration or ejection fraction (EF) amongst patients who could be induced and those who could not be induced into ventricular arrhythmia at the time of standard electrophysiology study (EPS). All the patients who were studied for inducibility of ventricular arrhythmias between March 2003 and March 2004 (a total of 137 patients) were included in the study. An EF less than or equal to 30% was used to define decreased EF, and a QRS width greater than 120 ms was used to define widened QRS width. Patients were studied using standard EPS protocol after obtaining informed consent. In the univariate analysis, increasing age, male gender and low EF were predictors of inducibility, while widened QRS width did not have any predictive value. With multivariate analysis, there was a significant increase in the odds of inducibility with decreasing EF and widened QRS width. Interestingly, males had significantly more numbers of positive results.