Transvenous versus open chest lead placement for resynchronization therapy in patients with heart failure： comparison of ventricular electromechanical synchronicity

Background Transvenous lead placement is the standard approach for left ventricular （LV） pacing in cardiac resynchronization ther- apy （CRT）, while the open chest access epicardial lead placement is currently the most frequently used second choice. Our study aimed to compare the ventricular electromechanical synchronicity in patients with heart failure after CRT with these two different LV pacing tech- niques. Methods We enrolled 33 consecutive patients with refractory heart failure secondly to dilated cardiomyopathy who were eligible for CRT in this study. Nineteen patients received transvenous （TV group） while 14 received open chest （OP group） LV lead pacing. Intraand inter-ventricular electromechanical synchronicity was assessed by tissue Doppler imaging （TDI） before and one year after CRT procedure. Results Before CRT procedure, the mean QRS-duration, maximum time difference to systolic peak velocity among 12 left ventricle segments （LV Ts-12）, standard deviation of time difference to systolic peak velocity of 12 left ventricle segments （LV Ts-SD）, and inter-ventficular mechanical delay （IVMD） in OP and TV group were 166 ± 17 ms and 170 ± 21 ms, 391 ±42 ms and 397 ± 36 ms, 144 ± 30 ms and 148 ± 22 ms, 58 ± 25 ms and 60 ± 36 ms, respectively （all P 〉 0.05）. At one year after the CRT, the mean QRS-duration, LV Ts-12, LV Ts-SD, and IVMD in TV and OP group were 128 ± 14 ms and 141 ± 22 ms （P = 0.031）, 136 ± 37 ms and 294 ± 119 ms （P = 0.023）, 50± 22 ms and 96 ± 34 ms （P = 0.015）, 27 ± 11 ms and 27 ± 26 ms （P = 0.86）, respectively. The LV lead implantation procedure time was 53.4±16.3 rain for OP group and 136 ± 35.1 min for TV group （P = 0.016）. The mean LV pacing threshold increased significantly from 1.7 ± 0.6 V/0.5 ms to 2.3 ± 1.6 V/0.5 ms （P 〈 0.05） in TV group while it remained stable in the OP group. Conclusions Compared to conventional endovascular approach, open chest access of LV pacing for CRT leads to better improvement of the intraventricular synchronization.

Comparison of Clinical Effects between Percutaneous Transluminal Septal Myocardial Ablation and Modified Morrow Septal Myectomy on Patients with Hypertrophic Cardiomyopathy

Background： Percutaneous transluminal septal myocardial ablation （PTSMA） and modified Morrow septal myectomy （MMSM） are two invasive strategies used to relieve obstruction in patients with hypertrophic cardiomyopathy （HCM）. This study aimed to determine the clinical outcome of these two strategies. Methods： From January 2011 to January 2015,226 patients with HCM were treated, 68 by PTSMA and 158 by MMSM. Both ultrasonic cardiograms and heart functional class were recorded before, alter operations and in the follow-up. Categorical variables were compared using Chi-square or Fisher＇s exact tests. Quantitative variables were compared using the paired samples t-test. Results： lnterventricular septal thickness was significantly reduced in both groups （21.27 ± 4.43 mm vs. 18.72 ±4.13 mm for PTSMA, t = 3.469, P 〈 0.001, and 21.83± 5.03 mm vs. 16.57 ± 3.95 mm for MMSM, t = 10.349, P 〈 0.001, respectively）. The left ventricular outflow tract （LVOT） pressure gradient （PG） significantly decreased after the operations in two groups （70.30 ± 44.79 mmHg vs. 39.78 ±22.07 mmHg for PTSMA, t = 5.041, P 〈 0.001, and 74.58 ± 45.52 mmHg vs. 13.95 ± 9.94 mmHg for MMSM, t = 16.357, P 〈 0.001, respectively）. Seven patients （10.29%） in the PTSMA group required a repeat operation in the follow-up. Eight （11.76%） patients were evaluated for New York I-lean Association （NYHA） Ill/IV in the PTSMA group, which was significantly more than the five （3.16%） in the same NYHA classes lbr the MMSM group at follow-up. Less than 15% of patients in the PTSMA group and none of the patients in the MMSM group complained of chest pain during follow-up. Conclusions： Both strategies can not only relieve LVOT PG but also improve heart function in patients with HCM. However, MMSM might provide a more reliable reduction in gradients compared to PTSMA.