QRS PROLONGATION IS ASSOCIATED WITH INDUCIBLE VENTRICULAR-TACHYCARDIAAFTER REPAIR OF TETRALOGY OF FALLOT

Prolonged QRS duration on the electrocardiogram has been found to pred ict adverse arrhythmic events in patients late after repair of tetralo gy of Fallot. Whether QRS duration can also predict inducible ventricu lar tachycardia (VT) at electrophysiologic study is unknown. Between 1 984 and 1995 we studied 135 survivors of tetralogy of Fallot surgery w hose age at surgery was 34 days to 37 years (3.7 +/- 3.9, median 2.5) and age at electrophysiologic study was 1.4 to 43 years (9.7 +/- 8.2, median 6.7). QRS duration was 80 to 240 ms (137 +/- 29) and greater th an or equal to 180 ms in 9 patients. Sustained VT was induced in 22 pa tients (monomorphic in 17). induced sustained monomorphic VT was relat ed to QRS duration, right ventricular dimension, H-V interval, and pre sence of symptoms. QRS duration was also related to induced sustained monomorphic VT by multivariate analysis. QRS duration greater than or equal to 180 ms was 35% sensitive and 97% specific for induced sustain ed monomorphic VT. QRS duration was related to induced sustained monom orphic VT even when only asymptomatic patients were analyzed. A QRS du ration greater than or equal to 180 ms was 100% sensitive and 96% spec ific for detecting clinical VT. Prolonged QRS duration on the electroc ardiogram is associated with induced sustained monomorphic VT on elect rophysiologic study. The finding of prolonged QRS duration should sugg est the need for further testing to determine the risk of adverse arrh ythmic events in patients after repair of tetralogy of Fallot, even if they are asymptomatic. (C) 1997 by Excerpta Medica, Inc.