| Abstrakt: |
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. [ABSTRACT FROM AUTHOR] |
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