Comparative outcomes of subcutaneous and transvenous cardioverter-defibrillators / 中华医学杂志(英文版)

BACKGROUND@#The comparative outcomes of subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous ICD (T-ICD) have not been well studied. The aim of this study was to evaluate the safety and efficacy of currently available S-ICD and T-ICD.@*METHODS@#The study included 86 patients who received an S-ICD and 1:1 matched to those who received single-chamber T-ICD by gender, age, diagnosis, left ventricular ejection fraction (LVEF), and implant year. The clinical outcomes and implant complications were compared between the two groups.@*RESULTS@#The mean age of the 172 patients was 45 years, and 129 (75%) were male. The most common cardiac condition was hypertrophic cardiomyopathy (HCM, 37.8%). The mean LVEF was 50%. At a mean follow-up of 23 months, the appropriate and inappropriate ICD therapy rate were 1.2% vs. 4.7% (χ = 1.854, P = 0.368) and 9.3% vs. 3.5% (χ = 2.428, P = 0.211) in S-ICD and T-ICD groups respectively. There were no significant differences in device-related major and minor complications between the two groups (7.0% vs. 3.5%, χ = 1.055, P = 0.496). The S-ICD group had higher T-wave oversensing than T-ICD group (9.3% vs. 0%, χ = 8.390, P = 0.007). Sixty-five patients had HCM (32 in S-ICD and 33 in T-ICD). The incidence of major complications was not significantly different between the two groups.@*CONCLUSIONS@#The efficacy of an S-ICD is comparable to that of T-ICD, especially in a dominantly HCM patient population. The S-ICD is associated with fewer major complications demanding reoperation.

Left ventricular 12 segmental strain imaging predicts response to cardiac resynchronization therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The number of non-responders to cardiac resynchronization therapy (CRT) exposes the need for better patient selection criteria for CRT. This study aimed to identify echocardiographic parameters that would predict the response to CRT.</p><p><b>METHODS</b>Forty-five consecutive patients receiving CRT-D implantation for heart failure (HF) were included in this prospective study. New York Heart Association (NYHA) class, 6-minute walk distance, electrograph character, and multi echocardiographic parameters, especially in strain patterns, were measured and compared before and six months after CRT in the responder and non-responder groups. Response to CRT was defined as a decrease in left ventricular endsystolic volume (LVESV) of 15% or more at 6-month follow up.</p><p><b>RESULTS</b>Twenty-two (48.9%) patients demonstrated a response to CRT at 6-month follow-up. Significant improvement in NYHA class (P < 0.01), left ventricular end-diastolic volume (LVEDV) (P < 0.01), and 6-minute walk distance (P < 0.01) was shown in this group. Although there was an interventricular mechanical delay determined by the difference between left and right ventricular pre-ejection intervals ((42.87 ± 19.64) ms vs. (29.43 ± 18.19) ms, P = 0.02), the standard deviation of time to peak myocardial strain among 12 basal, mid and apical segments (Tε-SD) ((119.97 ± 43.32) ms vs. (86.62 ± 36.86) ms, P = 0.01) and the non-ischemic etiology (P = 0.03) were significantly higher in responders than non-responders, only the Tε-SD (OR = 1.02, 95% CI = 1.01 - 1.04, P = 0.02) proved to be a favorable predictor of CRT response after multivariate Logistic regression analysis.</p><p><b>CONCLUSION</b>The left ventricular 12 segmental strain imaging is a promising echocardiographic parameter for predicting CRT response.</p>

Effect of ablation of complex fractionated atrial electrogram on vagal modulation in dogs / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Clinical observations have shown that the complex fractionated atrial electrogram (CFAE) associates with ganglionated plexus activity in the cardiac autonomic nervous system. This study aimed to investigate the impact of CFAE ablation on vagal modulation to atria and vulnerability to develop atrial fibrillation (AF).</p><p><b>METHODS</b>Ten adult mongrel dogs were involved. Cervical sympathovagal trunks were decentralized and sympathetic effects were blocked. CFAE was color tagged on the atrial 3-dimensional image and ablated during AF induced by S1S2 programmed stimulation plus sympathovagal trunk stimulation. Atrial effective refractory period (ERP) and vulnerability window (VW) of AF were measured on baseline and at vagal stimulation at 4 atrium sites. Serial tissue sections from ablative and control specimens received hematoxylin and eosin staining for microscopic examination.</p><p><b>RESULTS</b>Most CFAE areas were localized at the right superior pulmonary quadrant, distal coronary sinus (CS(d)) quadrant, and proximal coronary sinus (CS(p)) quadrant (21.74%, separately). Sinus rhythm cycle length (SCL) shortening did not decrease significantly after ablation at the sites, including right atrial appendage, left atrial appendage, CS(d), and CS(p) (P > 0.05). ERP shortening during vagal stimulation significantly decreased after ablation (P < 0.01); the VW to vagal stimulation significantly decreased after ablation (P < 0.05). The architecture of individual ganglia altered after ablation.</p><p><b>CONCLUSIONS</b>CFAE has an autonomic basis in dogs. The decreased SCL and ERP shortening to vagal stimulation after CFAE ablation demonstrate that CFAE ablation attenuates vagal modulation to the atria, thereby suppressing AF mediated by enhanced vagal activity. CFAE ablation could suppress AF mediated by enhanced vagal activity.</p>