Cardiac Resynchronization Therapy: Current Guidelines and Recent Advances Beyond Drug Treatment
Christian Butter1,2, Martin Seifert1,2, Christian Georgi1,2
1Cardiology Department, Immanuel Klinikum Bernau Herz-Zentrum Brandenburg, University of Brandenburg, Bernau, Germany.
Insights
Cardiac resynchronization therapy (CRT) is a key treatment for heart failure (HF) with left bundle branch block (LBBB). Newer pacing strategies show promise, potentially reducing the need for implantable cardioverter-defibrillators (ICDs).
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is recommended for heart failure (HF) patients with left bundle branch block (LBBB) and reduced ejection fraction, alongside optimal medical therapy (OMT).
- Atrial fibrillation (AF) and the need for right ventricular pacing influence CRT decisions.
- Advancements in pacing offer alternatives when CRT is not feasible or effective.
Purpose of the Study:
- To review current guidelines and emerging strategies for CRT in heart failure.
- To discuss the role of alternative pacing techniques and their long-term efficacy.
- To evaluate the evolving indications for implantable cardioverter-defibrillators (ICDs) in light of improved heart failure therapies.
Main Methods:
- Review of 2021 European Society of Cardiology (ESC) Guidelines for cardiac pacing and CRT.
- Analysis of alternative pacing sites and multi-lead/multi-site strategies.
- Discussion of conduction system pacing and its potential benefits.
- Consideration of the impact of advanced heart failure pharmacotherapy on device therapy decisions.
Main Results:
- CRT is emphasized for specific HF/LBBB patient profiles (LVEF ≤ 35%, QRS ≥ 150 ms).
- AV nodal ablation is relevant for AF patients undergoing CRT.
- Multi-lead/multi-site pacing and conduction system pacing show superiority or promise over traditional CRT.
- Improved medical therapy may obviate the need for ICD in some patients.
Conclusions:
- CRT remains crucial for selected heart failure patients, with evolving guidelines.
- Novel pacing strategies offer promising alternatives and potential improvements over standard CRT.
- The necessity of ICDs should be individualized, considering the impact of optimized medical therapy on left ventricular function.
Abstract:
Cardiac resynchronization therapy (CRT) is the therapy of choice for patients with symptomatic systolic heart failure (HF) and left bundle branch block (LBBB), despite optimal medical therapy (OMT). The recently published 2021 European Society of Cardiology (ESC) Guidelines on cardiac pacing and cardiac resynchronization therapy highlight the importance of CRT on top of OMT in HF patients with left ventricular ejection fraction (LVEF) ≤ 35%, sinus rhythm and typical LBBB with QRS duration ≥ 150 ms. In the presence of medically intractable or recurrent after catheter ablation atrial fibrillation (AF), AV nodal ablation as an adjuvant therapy becomes more relevant in patients qualifying for the implantation of a biventricular system. Furthermore, CRT may be considered in cases when increased pacing of the right ventricle is not desirable. However, alternative pacing sites and strategies are currently available, if the CRT is not feasible and effective in patients. However, strategies targeting "multi-sides" or using "multi-leads" have shown superiority over classic CRT. On the other hand, conduction system pacing seems to be a promising technique. Although early results are positive, consistency during the long term is pending. The indication for additional defibrillation therapy (ICD) may occasionally be unnecessary and has to be considered individually. Due to the great development and success of heart failure drug therapy, its positive effect on LV function can lead to enormous improvement. Physicians must await these effects and findings, which hopefully could lead to a relevant LV improvement resulting in a definitive decision against an ICD.
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