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ECG patterns of successful permanent left bundle branch area pacing in bradycardia patients with typical bundle branch block
Author(s) -
Li Xiaofei,
Fan Xiaohan,
Li Hui,
Ning Xiaohui,
Liang Erpeng,
Ma Wentao,
Wang Hao,
Liu Zhimin,
Yao Yan
Publication year - 2020
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/pace.13982
Subject(s) - medicine , qrs complex , bradycardia , cardiology , left bundle branch block , ejection fraction , right bundle branch block , bundle branch block , electrocardiography , heart rate , heart failure , blood pressure
Aim To assess the electrocardiogram patterns of paced QRS narrowing after successful left bundle branch area pacing (LBBAP) and echocardiographic measurements in patients with bradycardia and bundle branch block (BBB). Methods We prospectively enrolled 55 consecutive bradycardia patients with BBB and left ventricular ejection fraction ≥40% who had attempted LBBAP. Successful LBBAP was defined as paced QRS morphology of a right BBB (RBBB) pattern in lead V1 and a recording of abruptly shortened and then constant stimulus to peak left ventricular activation time with high and low output. Pacing characteristics and echocardiographic measurements were evaluated perioperatively and at 6‐month follow‐up. Results The success rate of LBBAP was 83.6% in patients with BBB, and median cumulative X‐ray dose‐area product was 100.5 µGym 2 (60.0, 179.3). LBBAP was successful in 19 of 26 patients with left BBB (LBBB) (73.1%) and in 27 of 29 patients with RBBB (93.1%). The QRS duration (QRSd) was significantly shortened in patients with LBBB (QRSd 169.4 ± 22.6 to 119.6 ± 9.5 ms), and five forms of QRSd narrowing were observed in patients with RBBB with the mean QRSd shortened from 143.1 ± 16.6 ms to 119.5 ± 11.7 ms. The thresholds for narrowing of QRSd were higher in RBBB than LBBB (1.74 ± 0.36 V/0.4 ms vs 0.79 ± 0.17 V/0.4 ms, P < .001). During the 6‐month follow‐up, both left and right ventricular synchronies were improved, and narrow QRSd persisted in patients with BBB. Conclusion In most bradycardia patients, RBBB could be completely or partially narrowed by LBBAP at different pacing models in addition to the correction of LBBB with LBBAP.