Improvement in electrocardiographic parameters of repolarization related to sudden death in patients with ventricular dysfunction and left bundle branch block after cardiac resynchronization through His bundle pacing.

BACKGROUND: Cardiac resynchronization therapy (CRT) through permanent His bundle pacing (p-HBP) normalizes interventricular conduction disorders and QRS. Similarly, there are immediate and long-term changes in repolarization, which could be prognostic of a lower risk of sudden death (SD) at follow-up. We aimed to compare the changes in different electrocardiographic (ECG) repolarization parameters related to the risk of SD before and after CRT through p-HBP. METHODS: In this prospective, descriptive single-center study (May 2019 to December 2021), we compared the ECG parameters of repolarization related to SD in patients with non-ischemic dilated cardiomyopathy, left bundle branch block (LBBB), and CRT indications, at baseline and after CRT through p-HBP. RESULTS: Forty-three patients were included. Compared to baseline, after CRT through p-HBP, there were immediate significant changes in the QT interval (ms): 445 [407.5-480] vs 410 [385-440] (p = 0.006), QT dispersion (ms): 80 [60-100] vs 40 [40-65] (p < 0.001), Tp-Te (ms): 90 [80-110] vs 80 [60-95] (p < 0.001), Tp-Te/QT ratio: 0.22 [0.19-0.23] vs 0.19 [0.16-0.21] (p < 0.001), T wave amplitude (mm): 6.25 [4.88-10] vs - 2.5 [- 7-2.25] (p < 0.001), and T wave duration (ms): 190 [157.5-200] vs 140 [120-160] (p = 0.001). In the cases of the corrected QT (Bazzett and Friederichia) and the Tp-Te dispersion, changes only became significant at 1 month post-implant (468.5 [428.8-501.5] vs 440 [410-475.25] (p = 0.015); 462.5 [420.8-488.8] vs 440 [400-452.5] (p = 0.004), and 40 [30-52.5] vs 30 [20-40] (p < 0.001), respectively) (Table 1). Finally, two parameters did not improve until 6 months post-implant: the rdT/JT index, 0.25 [0.21-0.28] baseline vs 0.20 [0.19-0.23] 6 months post-implant (p = 0.011), and the JT interval, 300 [240-340] baseline vs 280 [257-302] 6 months post-implant (p = 0.027). Additionally, most of the parameters continued improving as compared with immediate post-implantation. CONCLUSIONS: After CRT through His bundle pacing and LBBB correction, there was an improvement in all parameters of repolarization related to increased SD reported in the literature.

Cardiac resynchronization therapy in non-ischemic cardiomyopathy: a comparative non-randomized study of His Bundle pacing versus biventricular pacing.

BACKGROUND: Cardiac resynchronization therapy (CRT) via permanent His bundle pacing (pHBP) has gained acceptance globally, but robust studies comparing pHBP-CRT with classic CRT are lacking. In this study, we aimed to compare the improvement in left ventricular ejection fraction (LVEF) after pHBP-CRT versus classic CRT. METHODS: This was a single-center study comparing a prospective series of pHBP-CRT with a historical series of CRT via classic biventricular pacing (BVP). Patients with non-ischemic cardiomyopathy, baseline LVEF < 35%, left bundle branch block (LBBB), and CRT indications were selected. RESULTS: Fifty-one patients underwent classic CRT and 52 patients underwent pHBP-CRT. In the classic CRT group, the median (interquartile range) basal LVEF was 30% (IQR, 29-35%) before implantation and 40% (35-48%) at follow-up. In the pHBP-CRT group, the median basal LVEF was 30% (28-34%) before implantation and 55% (45-60%) at follow-up, with significant differences between both modalities at follow-up (p = 0.001). The median long term His recruitment threshold with LBBB correction was 1.25 (1-2.5) V at 0.4 ms in cases of pHBP-CRT, compared to a left ventricular coronary sinus threshold of 1.25 (1-1.75) V in cases of classic CRT (p = 0.48). After CRT, the median paced QRS was 135 (120-145) ms for pHBP-CRT versus 140 (130-150) ms for BVP-CRT (p = 0.586). CONCLUSIONS: The improvement in LVEF was superior with pHBP-CRT than with classic CRT. The thresholds at follow-up were similar in both groups.

Vitamin K Antagonists and Direct Oral Anticoagulants in Nonagenarian Patients With Atrial Fibrillation.

OBJECTIVES: Nonagenarian patients are underrepresented in clinical trials that have evaluated oral anticoagulation in patients with atrial fibrillation (AF). The aim of this study was to assess the pronostic impact of oral anticoagulation in patients with AF age ≥90 years. DESIGN: Retrospective multicenter study of nonagenarian patients with AF. SETTING AND PARTICIPANTS: A total of 1750 nonagenarian inpatients and outpatients with nonvalvular AF between January 2013 and December 2018 in 3 Spanish health areas were studied. METHODS: Patients were divided into 3 groups based on antithrombotic therapy: nonoral anticoagulants (30.5%), vitamin-K antagonists (VKAs; 28.6%), and direct oral anticoagulants (DOACs; 40.9%). During a mean follow-up of 23.6 ± 6.6 months, efficacy outcomes (death and embolic events) were evaluated using a Cox regression analysis and safety outcomes (bleeding requiring hospitalization) by competing-risk regression. Results were complemented with a propensity score matching analysis. RESULTS: During follow-up, 988 patients died (56.5%), 180 had embolic events (10.3%), and 186 had major bleeding (10.6%). After multivariable adjustment, DOACs were associated with a lower risk of death and embolic events than nonanticoagulation [hazard ratio (HR) 0.75, 95% confidence interval (CI)] 0.61‒0.92), but VKAs were not (HR 0.87, 95% CI 0.72‒1.05). These results were confirmed after propensity score matching analysis. For bleeding, both DOACs and VKAs proved to be associated with a higher risk (HR for DOAC 1.43; 95% CI 0.97‒2.13; HR for VKA 1.94; 95% CI 1.31‒2.88), although findings for DOACs were not statistically significant (P = .074). For intracranial hemorrhage (ICH), only VKAs-not DOACs-presented a higher risk of ICH (HR 4.43; 95% CI 1.48‒13.31). CONCLUSIONS AND IMPLICATIONS: In nonagenarian patients with AF, DOACs led to a reduction in mortality and embolic events in comparison with nonanticoagulation. This reduction was not observed with VKAs. Although both DOACs and VKAs increased the risk of bleeding, only VKAs were associated with higher ICH rates.