Reduction of QRS duration after pulmonary valve replacement in adult Fallot patients is related to reduction of right ventricular volume

AIMS: Late after total correction, Fallot patients with a long QRS duration are prone to serious arrhythmias and sudden cardiac death. Pulmonary regurgitation is a common cause of right ventricular (RV) failure and QRS lengthening. We studied the effects of pulmonary valve replacement (PVR) on QRS duration and RV volume. METHODS AND RESULTS: Twenty-six consecutive Fallot patients were evaluated both pre-operatively and 6-12 months post-operatively by cardiac magnetic resonance (CMR). In this study, we present the computer-assisted analysis of the standard 12-lead electrocardiograms closest in time to the CMR studies. For the whole group, QRS duration shortened by 6+/-8 ms, from 151+/-30 to 144+/-29 ms (P=0.002). QRS duration decreased in 18 of 26 patients by 10+/-6 ms, from 152+/-32 to 142+/-31 ms. QRS duration remained constant or increased slightly in eight of 26 patients by 3+/-3 ms, from 148+/-27 to 151+/-25 ms. CMR showed a decrease in RV end-diastolic volume from 305+/-87 to 210+/-62 mL (P=0.000004). QRS duration changes correlated with RV end-diastolic volume changes (r=0.54, P=0.01). CONCLUSION: Our study shows that PVR reduces QRS duration. The amount of QRS reduction is related to the success of the operation, as expressed by the reduction in RV end-diastolic volume.