A Novel Analysis Program Using 64-Multidetector Row Computed Tomography for the Evaluation of Left Ventricular Mechanical Dyssynchrony

Objectives: To explore the potential of a novel 64-multidetector row computed tomography (64-MDCT) program (SynchroGRAF), work in progress) for the evaluation of left ventricular mechanical dyssynchrony (LVMD). Methods: Twelve patients with depressed LV and wide QRS (P group: LVEF=31.0±7.8%, QRS=160.9±19.1 ms) and fifteen controls (N group: LVEF=68.8±7.0%, QRS=89.0±7.5 ms) were assessed with respect to LVMD using a 64-MDCT program. The program is capable of time-thickness analysis and can visualize regional LV wall thickening timing during a cardiac cycle. To evaluate LVMD, we used systolic dyssynchrony index (SDI) that was defined as standard deviation of time to maximal wall thickening of 17 LV segments×100/RR. Results: SDI of P group was significantly greater than that of N group (14.6±4.7 vs. 3.9±1.4, p=0.0001). The case of a 80 year old male with non-ischemic cardiomyopathy with a QRS duration 188 ms, underwent cardiac resynchronization therapy (CRT) and showed clinical improvement with marked LV reverse remodeling. In whom SynchroGRAF successfully demonstrated baseline LV dyssynchrony and resynchronization achieved by CRT asevidenced by a significant decrease in SDI (21.2 to 7.5). Conclusion: This preliminary finding implies the potential utility of the program for LVMD evaluation. Quantitative assessment of dyssynchrony may be possible using this novel method, but further evaluation of the methodology is required.