Limitations
This was a single center study with limited number of patients. Our protocol did not go beyond 20 mcg/kg/min of dobutamine and does not qualify as a high dose dobutamine study. Anesthesia was not uniformly given with either general anesthesia or conscious sedation, which may have had variable effects on the cardiac conduction. In addition, anti-arrhythmic and/or rate control agents were not uniformly held before the procedure as the decision was up to the electrophysiologist based on the individual patient. Selection of patients was not consecutive because it was not always feasible to perform the study protocol due to time constraints. Moreover, we did not perform a VABCL or VERP in 13 patients who underwent AF ablations given the length of the procedure and the effect of ventricular pacing on the blood pressure. There were other limited missing variables which the authors deemed insignificant. Exclusion of patients due to time constraints could possibly introduce bias and affect the study results, especially if we excluded patients when procedures were long. Safety is always the priority, and if patients were under anesthesia for a prolonged period, we did not want to extend the procedure and place the patient at greater risk. Therefore, the more complicated, sicker patients with more cardiac substrate and longer procedure times (those patients undergoing atrial fibrillation ablation) were either excluded or ventricular pacing was not performed. Patients included in this study underwent electrophysiologic testing for a variety of indications. The heterogeneity of indications must be considered when interpreting results.