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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
[Immediate effect of cardiac resynchronization therapy by tissue synchronization imaging and tissue tracking in
Hao-ying Shi1, Cui-zhen Pan, Xian-hong Shu
1Department of Cardiology, First Affiliated Hospital, Shanghai Jiaotong University, Shanghai 200080, China.
Objective:
To evaluate the immediate effect of cardiac resynchronization therapy (CRT) by Doppler tissue imaging (DTI), tissue synchronization imaging (TSI) and tissue tracking imaging (TTI) in patients with congestive heart failure.
Methods:
Ten patients with congestive heart failure who had cardiac resynchronization therapy were enrolled. The TSI and TTI imaging were performed by GE vivid 7 with M3s probe. The TTI image was obtained in diastole to determine delayed longitude contraction (DLC). The left ventricular ejection fraction (LVEF), the percentage of delayed longitude contraction segments (DLC), the standard deviation of the time to peak myocardial systolic contraction of 16 segments (Ts-SD), the standard deviation of the time to peak myocardial diastole of 16 segments (Td-SD), the systolic velocity of right ventricule (RV-Sm) and the average systolic velocity of mitral valve annulus (LV-Sm) were measured. The intraventricular dyssynchrony could be semi-quantified by TSI as 4 (red), 3 (orange), 2 (yellow), 1 (green), and the average value of 16 segments was defined as the TSI index. The immediate changes of these parameters were investigated when the pacemaker was turned on and off. The correlation of the Ts and TSI index was also analyzed.
Results:
When the pacemaker was on, the LVEF improved significantly from (37 +/- 11.30)% to (46 +/- 10.10)% (P < 0.01), and LV-Sm increased significantly from (3.16 +/- 0.87) cm/s to (3.76 +/- 0.74) cm/s (P < 0.01), RV-Sm increased significantly from (6.79 +/- 1.78) cm/s to (7.75 +/- 1.92) cm/s (P < 0.01). DLCs decreased significantly from (35 +/- 6.04)% to (18.13 +/- 9.97)% (P < 0.01), Ts-SD decreased from (83.97 +/- 33.02) ms to (52.67 +/- 19.65) ms, P < 0.05, Td-SD decreased from (87.81 +/- 22.34) ms to (63.45 +/- 31.49) ms, P < 0.05 and TSI index reduced from 2.11 +/- 0.15 to 1.60 +/- 0.33 (P < 0.01) respectively. In addition, the reduction of TSI index correlated significantly with that of Ts-SD (r = 0.75, P < 0.05).
Conclusions:
CRT could immediately improve the systolic and diastolic synchrony of the left ventricle and ventricular function. TSI and TTI may be as the new effective modalities to assess the mechanical dyssynchrony. TSI index was direct and reliable in this study.
