Efficacy and tolerance of intravenous lorcainide in patients with normal and impaired intraventricular conduction.

The effectiveness and safety of intravenous lorcainide was evaluated in 14 patients with normal (QRS less than 110 ms) and in 9 patients with prolonged QRS duration (QRS greater than or equal to 110 ms) showing chronic high frequency premature ventricular complexes (mean value of PVCs 17 min-1). Lorcainide was infused intravenously by intermittent bolus at 10 mg every minute to a total dose of 160 mg with exception of 5 patients with a prolonged QRS duration who only received 100 mg. The overall reduction of PVCs 1 hour after administration of the drug was 86% (p less than 0.05) in the patients with normal QRS duration and 98.5% (p less than 0.05) in the patients with a prolonged QRS duration. The mean plasma drug level achieved 1 h after treatment was 280 +/- 60 ng/ml in the patients with QRS less than 110 ms and 170 +/- 40 ng/ml in the patients with a QRS greater than or equal to 110 ms. Heart rate and blood pressure did not change but a significant increase (p less than 0.05) in QRS duration (+37%) was observed 30 min after the infusion of 160 mg lorcainide in the patient group with normal QRS duration. Lorcainide was well tolerated. Mild adverse effects were observed in five patients including: warmth sensation, vomiting, paresthesias, transient hypotension and the development of a junctional escape rhythm. Therefore lorcainide appears to be a safe and effective drug, that can even be administered to patients with a prolonged QRS duration.