Sudden cardiac death in congenital heart disease is related to increased right ventricular end-diastolic volume (RVEDV), abnormalities of QRS duration, and QRS, JT, and QT dispersions. Surgical pulmonary valve replacement and percutaneous pulmonary valve implantation (PPVI) decrease RVEDV, but the effects of PPVI on surface electrocardiographic parameters are unknown. PPVI represents a pure model of RV mechanical and electrophysiologic changes after replacement. This prospective study sought to determine the effects of PPVI on surface electrocardiographic parameters: Ninety-nine PPVI procedures in patients with congenital heart disease (23.1 ± 10 years of age) were studied before, after, and 1 year after PPVI with serial electrocardiograms and echocardiogram/magnetic resonance images. Forty-three percent had pulmonary stenosis, 27% pulmonary regurgitation (PR), and 29% mixed lesions. In those with predominantly PR (n = 26), QRS duration decreased significantly (135 ± 27 to 128 ± 29 ms, p = 0.007). However, in the total cohort no significant change in QRS duration at 1 year was observed (137 ± 29 to 134 ± 29 ms). Corrected QT interval and QRS, QT, and JT dispersions significantly decreased at 1 year (p ≤0.001). RVEDV correlated with preprocedure QRS duration (r = 0.34, p <0.002) but there was no correlation after PPVI. In conclusion, this is the first study reporting electrical remodeling after isolated PPVI and it confirms that decreases in QRS duration occur after PPVI in PR, as reported for equivalent surgical cohorts. Further, increased homogeneity of repolarization in combination with improved conduction may decrease arrhythmic events in congenital cardiac patients with pulmonary valvular disease.