Impact of Pulmonary Vein Anatomy on Long-term Outcome of Cryoballoon Ablation for Atrial Fibrillation

Variant pulmonary vein anatomy （PVA） has been reported to influence the recurrence of atrial fibrillation （AF） after radiofrequency ablation. However, the effects of PVA on AF in patients undergoing cryoballoon ablation （CBA） remain unknown. The present study aimed to examine the impact of PVA on the long-term outcome of CBA for AF. A total of 78 patients （mean age 60.7±10.9 years, 64.1% males） with symptomatic and drug-refractory paroxysmal AF were enrolled in the study. Left atrium （LA） and PVA acquired at computed tomography angiography （CTA） were reconstructed with CARTO 3 SYSTEM. Patients were routinely evaluated by 24-hour Holter monitoring following CBA. Cox regression was used to detect the predictors of AF recurrence after CBA. The results showed abnormal PVA in 30 patients （38.5%） and 18 patients （23.1%） had left common PV （LCPV）. Electrical pulmonary vein isolation was achieved in all patients. After a mean follow-up of 689.5±103.8 days, it was found that patients with abnormal PVA had similar AF recurrence rate to those with normal PVA （26.7% vs. 25.0%, P=0.54）, and there was no significant difference in AF recurrence rate between LCPV patients and non-LCPV patients （33.7% vs. 23.3%, P=0.29）. Cox regression analysis showed that AF duration （72.9±9.0 vs. 42.3±43.2 months, HR 1.001; 95%CI 1.003- 1.014; P〈0.001） and cryo-applications of right-side PVs （3.0±1.6 vs. 4.7±1.7, HR 0.661; 95% CI 0.473-0.925; P=0.016） were independent predictors of freedom from AF, but PVA was not identified as a predictor of long-term success. In conclusion, the variant PVA cannot significantly influence the long-term outcome of AF patients undergoing CBA; longer AF duration and less cryo-applications of right-side PVs are associated with higher AF recurrent rate.

Is right ventricular mid-septal pacing superior to apical pacing in patients with high degree atrio-ventricular block and moderately depressed left ventricular function?

Objective： We are aimed to investigate whether right ventricular mid-septal pacing （RVMSP） is superior to conventional right ventricular apical pacing （RVAP） in improving clinical functional capacity and left ventricular ejection fraction （LVEF） for patients with high-degree atrio-ventricular block and moderately depressed left ventricle （LV） function. Methods： Ninety-two patients with high-degree atrio-ventricular block and moderately reduced LVEF （ranging from 35% to 50%） were randomly allocated to RVMSP （n=45） and RVAP （n=47）. New York Heart Association （NYHA） functional class, echocardiographic LVEF, and distance during a 6-min walk test （6MWT） were determined at 18 months after pacemaker implantation. Serum levels of N-terminal pro-brain natriuretic peptide （NT-proBNP） were measured using an enzyme-linked immunosorbent assay （ELISA） kit. Results： Compared with baseline, NYHA functional class remained unchanged at 18 months, distance during 6MVVT （485 m vs. 517 m） and LVEF （36.7% vs. 41.8%） were increased, but BNP levels were reduced （2352 pg/ml vs. 710 pg/ml） in the RVMSP group compared with those in the RVAP group, especially in patients with LVEF 35%-40% （for all comparisons, P〈0.05）. However, clinical function capacity and LV function measurements were not significantly changed in patients with RVAP, despite the pacing measurements being similar in both groups, such as R-wave amplitude and capture threshold. Conclusions： RVMSP provides a better clinical utility, compared with RVAP, in patients with high-degree atrioventricular block and moderately depressed LV function whose LVEF levels ranged from 35% to 40%.