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Updated: Jul 17, 2026
Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Effect of left ventricular endocardial activation pattern on echocardiographic and clinical response to cardiac
Jeffrey W H Fung1, Joseph Y S Chan, Gabriel W K Yip
1Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR, China. jwhfung@cuhk.edu.hk
Objective:
To explore the left ventricular (LV) electrical activation pattern in heart failure (HF) and its implication to cardiac resynchronization therapy (CRT).
Design And Setting:
Observational study at the University Teaching Hospital.
Patients:
23 optimally treated patients with HF with New York Heart Association class III, QRS duration >120 ms and LV ejection fraction <35%.
Interventions:
The LV endocardial activation pattern and total activation time (Tat) was determined by non-contact mapping and the LV mechanical dys-synchrony was determined by standard deviation (Ts-SD) and maximal difference (Ts-diff) of time to peak systolic contraction (Ts) among 12 LV segments using tissue Doppler imaging before receiving CRT.
Main Outcome Measures:
Correlation between electrical and mechanical dys-synchrony; volumetric responder to CRT at 3 months; HF hospitalisation or death by Kaplan-Meier analysis.
Results:
Homogenous (type I, n = 8) and presence of conduction block (type II, n = 15) patterns were identified. Significant correlation between Tat and Ts-SD/Ts-diff was noted only in type II (r = 0.73/0.56, p = 0.002/0.03). Ts-SD and Ts-diff in type II were significantly longer than type I. 12 patients in type II and 2 in type I were CRT responders (p = 0.01). After 487 (447) days, patients with type II pattern had significantly lower risk of HF hospitalisation or death than those with type I (log rank chi(2) = 5.25; p = 0.02).
Conclusion:
Patients with type II LV endocardial activation pattern had a more favourable echocardiographic and clinical response to CRT than those with type I pattern.
