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.

His bundle pacing success and electrical parameter stability regardless of three-dimensional transthoracic echocardiography lead localization.

BACKGROUND OR PURPOSE: His bundle pacing (HBP) is the most physiological form of ventricular pacing. Few prospective studies have analyzed lead localization using imaging techniques and its relationship with electrical parameters and capture patterns. The objective of this study is to examine the correlation between electrical parameters and lead localization using three-dimensional transthoracic echocardiography (3D TTE). METHODS: This single-center, prospective, nonrandomized clinical research study (January 2018 to June 2020) included patients with an indication of permanent pacing, in whom 3D TTE was performed to define lead localization as supravalvular or subvalvular. RESULTS: A total of 92 patients were included: 56.5% of leads were supravalvular, and 43.5% were subvalvular, which resembles previous anatomic descriptions of autopsied hearts of His bundle localization within the triangle of Koch (ToK). R-wave sensing was higher when the His lead was localized subvalvular instead of supravalvular. His lead localization was not associated with HBP threshold or impedance differences, nor with the two different HBP patterns of capture, or with the ability of HBP to correct baseline BBB. The thresholds remained stable during follow-up visits, regardless of His lead localization. Higher R-wave sensing was observed during follow-up than at baseline, mainly in the subvalvular His leads. However, lead impedances in both positions decreased during follow-up. CONCLUSIONS: Lead localization in relation to the tricuspid valve did not influence the electrical performance of HBPs. Wide anatomical variations of the His bundle within the ToK explain our findings, reinforcing the idea that the technique for HBP should be fundamentally guided by electrophysiological and not anatomical parameters.

Incidence, predictors of bleeding and prognosis of bleeding in anticoagulated nonagenarian patients with atrial fibrillation.

BACKGROUND: The prevalence of atrial fibrillation (AF) increases with age. The prescription of anticoagulation in very elderly patients is controversial and sometimes underused. Our objective is to report the incidence and predictors of major bleeding in anticoagulated nonagenarian patients with non valvular atrial fibrillation (NVAF). METHODS: We analyzed a large multicentre registry of anticoagulated nonagenarian patients diagnosed with NVAF from three health areas of Spain, between 2013 and 2017. Predictors of major bleeding were studied with a competing risk analysis and the impact of major bleeding with a time-dependent mortality analysis. RESULTS: The incidence rate of major bleeding was 5 per100 person-year (95% Confidence Interval [CI]: 4.59-6.35), similar in the group of patients with vitamin K antagonists (VKAs) and direct oral anticoagulants (DOAC). In the VKAs group we found as predictors of major bleeding: previous admission for bleeding (sub-distribution hazard ratio [sHR] 3.25, 95% CI: 1.48-7.13), creatinine (sHR 1.38, 95% CI: 1.16-1.64,) and control out-of-range INR (sHR 1.90, 95% CI: 1.02-3.55). In DOAC group, male sex (sHR 1.92, 95% CI: 1.18-3.13) and the history of previous admission for bleeding (sHR 2.60, 95% CI 1.33-5.06) were found as a predictor. The HAS-BLED was not associated with major bleeding. Major bleeding was associated with increased mortality in both VKAs and DOAC groups without significant differences. CONCLUSIONS: We found an incidence rate of major bleeding with relative low values, similar in those treated with VKAs and those treated with DOAC, with different predictors of major bleeding in each group. Major bleeding was associated with increased mortality, with no significant difference by oral anticoagulation therapy (OAT).

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.