Internal flow fraction as a potential indicator of pulmonary valve replacement in tetralogy of Fallot patients

Abstract

Background Standard of care for TOF patients is a complete surgical repair in infancy but this results in free pulmonary regurgitation as no suitable long-term substitute for the obstructive valve is available. Although chronic pulmonary regurgitation can be well tolerated for decades, many patients (>20%) eventually develop right ventricular dysfunction and often require PVR. Determining the optimal timing of PVR is difficult, and there is no clear consensus within the medical community. In TOF patients before PVR, clinical studies have demonstrated a correlation between QRS duration and RV size with negative electromechanical interaction and dyssynchrony that progresses with RV enlargement. IFF is a quantitative measure of the energy loss throughout the cardiac cycle due to dyssynchronous contraction. We have developed a means of quantifying IFF noninvasively from cardiac magnetic resonance (CMR) images. In this study, we hypothesized that IFF within the left ventricle would increase in serial CMR exams prior to PVR.