The Paradoxical Adverse Effect of Verapamil for Treating Clinical Paroxysmal Supraventricular Tachycardia

摘要

The intravenous administration of verapamil to 2 patients with paroxysmal supraventricular tachycardia (PSVT) resulted in an induction of PSVT during a programmed electrophysiological stimulation study. Each patient had a documented episode of PSVT. Baseline programmed stimulation studies revealed neither induction of PSVT nor an atrial echo; however, PSVT was induced immediately after injecting verapamil (0.15mg/kg) intravenously in both patients. In 1 patient, the study was repeated 2 days later and similar results were obtained. The serum concentration of verapamil when PSVT was induced was about 80ng/ml in both cases. Clinicians using verapamil should note that this antiarrhythmic drug may aggravate PSVT, depending on critical changes in AV nodal conduction and refractoriness.