Related Experiment Video
Updated: Jul 5, 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
Future directions in cardiac resynchronization therapy
1Department of Cardiology, Karolinska University Hospital, 171 76 Solna, Sweden. Cecilia.linde@ki.se
Insights
Cardiac resynchronization therapy (CRT) improves outcomes for heart failure patients with wide QRS. Ongoing research explores CRT benefits in atrial fibrillation, mild heart failure, and preserved ejection fraction.
Area of Science:
- Cardiology
- Medical Devices
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is established for moderate-to-severe heart failure (NYHA class III-IV) with reduced ejection fraction and wide QRS, indicating ventricular dyssynchrony.
- Current research is evaluating CRT's efficacy in specific patient subgroups, including those with atrial fibrillation, mild heart failure, or a need for antibradycardia pacing.
Purpose of the Study:
- To assess the expanding role and refine patient selection criteria for CRT.
- To investigate if adding mechanical dyssynchrony criteria improves CRT response rates (PROSPECT trial).
- To determine if CRT benefits patients with narrow QRS but mechanical dyssynchrony (RethinQ study).
Main Methods:
- Review of existing clinical trial data and ongoing research.
- Analysis of patient subgroups based on QRS width, ejection fraction, and presence of mechanical dyssynchrony.
- Evaluation of CRT outcomes in patients with atrial fibrillation, mild heart failure, and heart failure with preserved ejection fraction.
Main Results:
- CRT is effective in selected heart failure patients with wide QRS and ventricular dyssynchrony.
- The benefit of CRT in patients with atrial fibrillation, mild heart failure, or narrow QRS is under investigation.
- The role of mechanical dyssynchrony in predicting CRT response is being actively studied.
Conclusions:
- CRT offers significant benefits for specific heart failure populations.
- Further research is needed to optimize CRT patient selection and expand its application.
- Identifying mechanical dyssynchrony may enhance CRT's effectiveness in broader patient groups.
Abstract:
Cardiac resynchronization therapy (CRT) reduces symptoms and improves mortality in patients with moderate to severe chronic heart failure (New York Heart Association class III-IV) in sinus rhythm with reduced left ventricular ejection fraction and with wide QRS on the surface electrocardiogram as evidence of ventricular dyssynchrony. CRT's benefit in patients with atrial fibrillation, mild heart failure, or a conventional indication for antibradycardia pacing is being assessed. Moreover, the PROSPECT trial assessed whether the response rate to CRT might increase if, in addition to wide QRS, mechanical dyssynchrony criteria were required. The RethinQ study examined whether patients with narrow QRS but with mechanical dyssynchrony benefit from CRT. Finally, whether patients with heart failure with preserved left ventricular function also may benefit from CRT remains to be studied.
Related Concept Videos
Heart Failure VI: Adjunct Therapies
Cardiomyopathy II: Dilated Cardiomyopathy
Cardiomyopathy V: Interprofessional Care
Cardiomyopathy III: Hypertrophic Cardiomyopathy
Heart Failure V: Medical Management
Heart Failure Drugs: Inotropic Agents

