Effect of selective intracoronary antiarrhythmic drug administration in sustained ventricular tachycardia.

The effect of selective intracoronary antiarrhythmic drug infusion on inducibility of cardiac arrhythmias was studied in 3 patients with recurrent sustained monomorphic ventricular tachycardia referred for comprehensive electrophysiologic studies. Each patient had evidence of prior myocardial infarction, 1 or more occluded coronary arteries and a readily identifiable collateral vessel that provided collateral flow to the infarct-related artery. In each patient, the clinical arrhythmia was reproducibly inducible by programmed stimulation in the control state. After positioning a small infusion catheter in the collateral vessel, selective intracoronary lidocaine 0.3 to 0.6 mg/min (patients 1 and 2) or procainamide 0.1 to 1.4 mg/min (patient 3) was infused for a 10-minute period. In each patient the clinical arrhythmia was rendered noninducible during selective intracoronary drug infusion. The arrhythmia was again inducible after a 10-minute drug-washout period and also after standard intravenous doses of antiarrhythmic drug. Selective intracoronary antiarrhythmic drug infusion may help to localize the site of origin of some cardiac arrhythmias, may provide a means of testing the effects of several drugs during a single study and may be a new method for studying mechanisms of action of antiarrhythmic drugs.