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.

Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

“…There also have been recent developments to quantitate the extent of right ventricular wall motion abnormalities by angiography using computer based analysis as well as to determine right ventricular volumes51,52 In addition, there is commercial software available to determine RV volumes and ejection fraction 53. The right ventricular angiogram obtained in multiple views is considered to be a reliable imaging test to assess wall motion abnormalities but requires considerable experience.…”

Three-Dimensional Electroanatomical Voltage Mapping and Histologic Evaluation of Myocardial Substrate in Right Ventricular Outflow Tract Tachycardia

“…Moreover, it is problematic to detect by current imaging techniques segmental ventricular lesions localized to the RVOT and RV anterior free wall (22,23). A recent angiographic study of computer-based quantitative segmental contraction analysis of the RV free wall demonstrated that wall motion is nonuniform in different RV regions: tricuspid valve zones show the greatest movement during contraction, whereas anterior and infundibular regions the least movement (24). In the present study, we demonstrated that EVM, by assessing the electrical rather than the mechanical effects of loss of RV myocardium, obviated limitations in RVOT wall motion analysis and increased the sensitivity for detecting otherwise concealed ARVC/D myocardial substrate.…”

Right ventricular morphology on catheter angiography: Variations and its implications for the diagnosis of arrhythmogenic right ventricular cardiomyopathy

“…Significant inter-observer variation in initial qualitative assessment was observed in our study, so where possible quantitative assessments should be used: measurement of indexed RV volumes is essential in our view. New software developments may improve assessment of regional wall motion abnormalities [9,18]. Simple dimension measurements may be helpful, as in our study, and the findings in our study may add to formulation of a reference range when similar techniques and views are used.…”