Electrophysiologic, hemodynamic and metabolic effects of intravenous bepridil hydrochloride

Bepridil, a fast and slow channel blocking drug, was administered intravenously over 5 minutes in a dose of 3 mg/kg body weight to 19 patients. Ten patients received intravenous bepridil during electrophysiologic study, performed for the investigation of known or suspected cardiac arrhythmias. Sinus cycle length increase from 764 +/- 56 to 886 +/- 62 ms (p less than 0.002). AH interval increased from 101 +/- 6.9 to 137 +/- 11.9 ms (p less than 0.01). HV and QRS durations were not significantly affected. QTc interval increased from 395 +/- 13 to 423 +/- 13 ms (p less than 0.001). Atrial effective refractory period increased from 211 +/- 8 to 242 +/- 8.7 ms (p less than 0.005), and atrioventricular nodal effective refractory period increased from 299 +/- 26 to 366 +/- 30 ms (p less than 0.02). Right ventricular effective refractory period increased from 233 +/- 9.3 to 259 +/- 8.1 ms (p less than 0.001). In an additional 9 patients with coronary artery disease, a hemodynamic and metabolic study was performed. A transient mean decrease dP/dt max from 1,646 +/- 164 to 1,506 +/- 238 mm Hg/s (p less than 0.05) and a mean increase of 2.6 mm Hg (p less than 0.05) in left ventricular end-diastolic pressure were observed. Both values had returned to control levels 15 minutes after drug infusion. Blood pressure, cardiac output, coronary sinus blood flow and myocardial lactate extraction ratio did not change significantly. This profile of powerful electrophysiologic and minor hemodynamic changes indicates a potentially useful role for bepridil in the acute management of supraventricular arrhythmias and, possibly, ventricular arrhythmias.