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Cardiac resynchronization therapy: device-based medicine for heart failure
1Quebec Heart Institute, Laval Hospital, Quebec City, Canada. francois.pholippon@med.ulaval.ca
Journal of Cardiac Surgery
|May 21, 2004
Summary
Cardiac resynchronization therapy (CRT) improves outcomes for advanced heart failure patients with conduction delays. CRT reduces mortality and hospitalizations, especially when combined with an implantable cardiac defibrillator (ICD).
Area of Science:
- Cardiology
- Medical Devices
- Heart Failure Management
Background:
- Advanced heart failure (HF) often involves left bundle branch block, causing left ventricular (LV) dyssynchrony and high mortality.
- Intraventricular conduction delays affect up to 25% of HF patients with QRS > 120 ms, worsening prognosis.
Purpose of the Study:
- To evaluate the efficacy of cardiac resynchronization therapy (CRT) as an adjunctive treatment for patients with advanced heart failure.
- To highlight the benefits of CRT in improving LV function, reducing symptoms, and enhancing patient outcomes.
Main Methods:
- CRT delivered transvenously via coronary sinus or epicardially.
- Analysis of clinical trial data, including the COMPANION trial, assessing outcomes like NYHA class, exercise capacity, and hospitalization rates.
Main Results:
- CRT significantly improves NYHA class and exercise capacity.
- CRT reduces hospitalization rates; the COMPANION trial showed a 43% reduction in mortality/hospitalization with CRT+ICD.
- CRT optimizes ejection fraction, reduces mitral regurgitation, and promotes LV remodeling.
Conclusions:
- CRT is a crucial option for symptomatic, refractory HF patients with reduced LV function and wide QRS, despite optimal medical therapy.
- Consider CRT with an ICD for patients with LV ejection fraction <30% and ischemic cardiomyopathy.
- Further research is needed on CRT responders, tissue Doppler imaging, total mortality impact, and CRT in specific conditions like dilated cardiomyopathy or atrial fibrillation.