[The prospective evolution of the efficacy of antiarrhythmia therapy in paroxysmal supraventricular tachycardia in patients with the ventricular pre-excitation syndrome].

Evolution of the effectiveness of antiarrhythmic drugs used in 240 patients with preexcitation syndrome to arrest episodes of paroxysmal supraventricular tachycardia was analysed prospectively. The first intravenous administration was effective in 97, 93.3, 80.9, 75, 70.3, 60, 48% of cases for novocainamid, verapamil, cordarone, disopyramide, ajmaline, ethacizine, mexitil and inderal, respectively. When observed in prospective evolution for 10-14 years, overall group efficacy dropped from 81.3% at first administration to 21.4%.