SUPRAVENTRICULAR TACHYCARDIA DUE TO SIMUL TANEOUS CONDUCTION IN A RAPID AND SLOW CONDUCTION PATHWAY - TREATMENT OF ABLATION OF THE SLOW PATHWAY

The authors report the case of a 70 year old woman with frequent attac ks of supraventricular tachycardia resistant to antiarrhythmic therapy . The tachycardia was irregular with predominantly normal QRS complexe s. Electrophysiological investigation showed dual conduction in the at rioventricular node and tachycardia was induced by atrial extrastimulu s. However, reentrant tachycardia could not be induced, the refractory period of the slow pathway being much longer than that of the rapid p athway. The mechanism of the tachycardia was simultaneous conduction o f the sinus rhythm through the two nodal conduction pathways. This was successfully treated by radiofrequency ablation of the slow pathway.