Do Patients with Right Ventricular Outflow Tract Ventricular Arrhythmias Have a Normal Right Ventricular Wall Motion?

Abstract

Background/Aim: Patients with ventricular ectopy from the right ventricular (RV) outflow tract (RVOT) are often referred for RV angiography to exclude disorders such as arrhythmogenic RV cardiomyopathy/dysplasia (ARVC/D). This is usually based on a qualitative assessment of the wall motion. We present a method to quantify the wall motion and to apply this method to compare patients with RVOT ectopy to normal subjects. Methods: RV angiograms were analyzed from 19 normal subjects and 11 subjects with RVOT ventricular arrhythmias (RVOT arrhythmia subjects) who had no other clinical or other evidence for ARVC/D. By a newly developed computer-based method, RV contours were first traced from multiple frames spanning the entire cardiac cycle. The fractional change in area between contours was then calculated as a serial function of time and location to determine both total contour area change and timing of contour movement. Contour area strain, defined as the differential change in area between nearby regions, was also computed. Results: The contour area change was greatest in the tricuspid valve region and least in the RVOT and midanterior regions. The onset of contraction was earliest in the RVOT region and latest in the apical, inferior, inferoapical, and subtricuspid valve regions. The contour strain was largest in superior tricuspid valve and inferior wall and near zero within the lateral tricuspid valve region. There were significant pairwise differences in contraction area, timing, and strain in the various regions. There were no significant differences between normal subjects and RVOT arrhythmia subjects. Conclusions: The RV wall motion is nonuniform in contour area change, strain, and timing of motion. Patients with RVOT ventricular ectopy demonstrate wall motion parameters similar to those of normal subjects. This technique should be applicable in analyzing RV wall motion in patients suspected of having ARVC/D.