Assessment of ventricular desynchronization in dilated cardiomyopathy by the automatic contour tracking method

Background. Automated contour tracking (ACT) method is an echocardiographic technique that provides an automatic assessment of endocardial border and left ventricular (LV) cavity area. The aim of the present study was to investigate if the pattern of LV volume curves variation using ACT can help in the differentiation of desynchronised ventricular contraction. Methods. Thirty-two patients with dilated cardiomyopathy and LV ejection fraction <35% were studied with tissue Doppler imaging (TDI) echocardiography and ACT. Interventricular delay (IVD) by TDI was defined as the absolute difference in time to peak systolic velocity between the basal septal and basal right ventricular wall. Intraventricular myocardial delay (IMD) was defined as the time interval from maximal contraction between interventricular septum and posterior, lateral and posterolateral wall using long axis and four chamber apical views. On line continuous LV volume changings were recorded using ACT and septal and lateral walls velocities and annular displacements were obtained. Interventricular and intraventricular myocardial delay was calculated from the RV/LV or intraventricular difference of the phase peaks determined by curve fitting of the histogram. Results. Ventricular desynchronization using TDI with IVD >40ms and IMD >65ms was found in 26 pts (20 pts QRS >120ms, 6 pts QRS <120ms). In these pts ACT parameters were significantly different compared to the remaining pts. Right annular displacement was delayed 24332ms and lateral velocity was delayed 23537ms. 14 pts were implanted with biventricular pacing and presented significant improvement of ACT parameters (216ms and 178ms respectively, p<0.001) and LV volume pattern of contraction. Conclusion. ACT is a useful tool in the evaluation of ventricular dyssynchrony and may be used in the follow-up of pts with biventricular pacing.