HOT CRT—The Effective Combination of Conventional Cardiac Resynchronization and His Bundle Pacing

Abstract

Background and Objectives: Cardiac Resynchronization Therapy (CRT) has, besides its benefits, various limitations. For instance, atrial fibrillation (AF) has a huge impact on the therapy efficacy. It usually reduces the overall BiV pacing percentage and leads, inevitably, to lack of fusion beats. In many patients with heart failure that could benefit from resynchronization, the QRS morphology is often IVCD and atypical, or non-LBBB, which further diminishes the CRT response. In those cases, we established His pacing combined with LV pacing as a feasible option to reduce the impact of AF on the CRT response and regain partially physiological ventricular activation to improve the electromechanical sequence. Materials and Methods: We implanted two patients with AF, HF, EF < 35%, NYHA II-III and QRS > 150 ms with CRT-D systems modified to HOT-CRT and observed their clinical, ECG and echocardiographic improvements over a follow-up period of three months. Results: In both patients we observed improvements of the initial parameters. We were able to shorten the QRS duration to approx. 120 ms, improve NYHA functional class, increase the EF by approximately 12% and distinctly reduce mitral regurgitation. Conclusion: Since the conventional CRT reaches its limits within this specific patient group, we need to consider alternative pacing sites and the effective combination of them. Our results and respectively other studies that are also mentioned in the current guidelines, support the feasibility of HOT-CRT in the above mentioned patient group.

Left ventricular electrical potential measured by the NOGA XP electromechanical mapping method as a predictor of response to cardiac resynchronization therapy

“…Pacing of the His bundle has been reported in many studies to have similar electroradiographic and hemodynamic effects compared to traditional biventricular pacing ( 4 , 5 ), although it is often associated with a slightly higher pacing threshold and LBBB correction is not possible in all cases ( 6 ). Alternatively, left bundle branch pacing ( 7 ), as well as combined pacing models including His bundle pacing and left ventricular pacing from the coronary sinus area are possible ( 8 , 9 ).…”

“…electroradiographic and hemodynamic effects compared to traditional biventricular pacing (4, 5), although it is often associated with a slightly higher pacing threshold and LBBB correction is not possible in all cases (6). Alternatively, left bundle branch pacing (7), as well as combined pacing models including His bundle pacing and left ventricular pacing from the coronary sinus area are possible (8,9). Each of the methods mentioned above has its limitations and new pacing modalities have yet to be evaluated in randomized clinical trials.…”

Cardiac electronic implantable devices: A call for a new coding system

“…CRT-P with the "right ventricular lead" at the LBB 3 3-R0D-0 CRT-D without atrial lead with His bundle pacing connected at the atrial port 4 3-0DV-E CRT-D without atrial lead with LBB pacing connected at the atrial port…”