However, it is not yet evident that this correlates with an improvement in mortality. Clinically, it therefore is most compelling to per- form pulmonary valve replacement if 2 of the fol- lowing are met:S4.3.5-1,S4.3.5-9,S4.3.5-12 S4.3.5-14 a. Mild or moderate RV or LV systolic dysfunction b. Severe RV dilation (RV end-diastolic volume , or RV end-systolic volume , or RV end-diastolic volume 2x LV end-diastolic volume). c. RV systolic pressure due to RVOT obstruction 2/3 systemic pressure d. Progressive reduction in objective exercise tolerance The increasing use of CMR in the long- term follow-up for patients with repaired TOF has provided quantification of ventricular size, function, and PR. However, there is lack of con- sensus regarding optimal indications and timing of pulmonary valve replacement in this popula- tion. Pulmonary valve replacement results in re- duction of RV volume and relief of PR; however, these are only surrogates for outcomes. Many patients with repaired TOF may deny symptoms yet demonstrate reduced exercise tolerance. Pulmonary valve replacement in such patients has been associated with improved functional 7. Risk factors for SCD include: a. LV systolic or diastolic dysfunction b. Nonsustained VT c. QRS duration 180 ms d. Extensive RV scarring e. Inducible sustained VT at electrophysiological study The largest study of patients with repaired TOF and ICDs included 121 patients from 11 North American and European sites followed for a median of 3.7 years after ICD implantation. 