His-optimized cardiac resynchronization therapy in a patient with heart failure and right bundle branch block: a case report

Abstract

Background Cardiac resynchronization therapy (CRT) is an option for treatment for chronic heart failure (HF) associated with left bundle branch block (LBBB). Patients with HF and right bundle branch block (RBBB) have potentially worse outcomes in comparison to LBBB. Traditional CRT in RBBB can increase mortality and HF deterioration rates over native disease progression. His bundle pacing may improve the results of CRT in those patients. Furthermore, atrioventricular node ablation (AVNA) for rate control in atrial fibrillation (AF) can be challenging in patients with previously implanted leads in His region. Case summary We report the case of 74-year-old gentleman with a 5-year history of HF, permanent AF with a rapid ventricular response, and RBBB. He was admitted to the hospital with complaints of severe weakness and shortness of breath. Left ventricular ejection fraction (LVEF) was decreased (41%), right ventricle (RV) was dilated (41 mm), and QRS was prolonged (200 ms) with RBBB morphology. The patient underwent His-optimized CRT with further left-sided AVNA. As a result, LVEF increased to 51%, RV dimensions decreased to 35 mm with an improvement of the clinical status during a 6-month follow-up. Discussion Patients with AF, RBBB, and HF represent the least evaluated clinical subgroup of individuals with less beneficial clinical outcomes according to CRT studies. Achieving the most effective resynchronization could require pacing fusion from sites beyond traditional with the intention to recruit intrinsic conduction pathways. This approach can be favourable for reducing RV dilatation, improving LVEF, and maximizing electrical resynchronization.

Overview of Current Strategies Aiming at Improving Response to Cardiac Resynchronization Therapy

“…In these studies, the superiority of HOT-CRT in terms of providing a shorter right ventricular activation time compared to other resynchronization techniques is remarkable, and in this respect, it is a candidate to be the ideal resynchronization method in patients with RBBB. 37 , 38 For patients with LBBB, it may be reasonable to prefer LOT-CRT, which is a fusion pacing method such as HOT-CRT. As a result of the trials conducted by the international LBBAP collaborative study group, it has been reported that LOT-CRT is a pacing technique that should be tried in patients who did not respond to BVP or whose response was insufficient due to the greater electrical resynchronization provided by LOT-CRT.…”