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Updated: Jun 26, 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
Six-minute walking test predicts long-term cardiac death in patients who received cardiac resynchronization therapy
María Angeles Castel1, Francisco Méndez, David Tamborero
1Thorax Clinic Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Villarroel 170 Barcelona 08036, Catalonia, Spain.
Insights
Baseline functional capacity and left ventricular ejection fraction predict long-term mortality in chronic heart failure patients receiving cardiac resynchronization therapy. A 6-minute walking test distance under 225 meters indicates high cardiovascular death risk.
Area of Science:
- Cardiology
- Heart Failure Management
- Medical Devices
Background:
- Cardiac resynchronization therapy (CRT) improves outcomes in chronic heart failure (CHF) with electrical dyssynchrony.
- Long-term mortality predictors in CRT-treated CHF patients require further investigation.
Purpose of the Study:
- To identify baseline predictors of long-term cardiovascular mortality in patients with moderate to severe CHF undergoing CRT.
Main Methods:
- A cohort of 155 moderate to severe CHF patients post-CRT implant were analyzed.
- Baseline data included clinical history, 6-minute walking test (6MWT), and echocardiography.
- Multivariate Cox regression identified independent predictors of cardiovascular mortality.
Main Results:
- Cardiovascular mortality occurred in 15.5% of patients over a mean follow-up of 24.4 months.
- Univariate analysis linked NYHA class, 6MWT distance, left atrial diameter, digoxin use, and LV ejection fraction to mortality.
- Independent predictors of mortality were lower LV ejection fraction and 6MWT distance <225 meters.
Conclusions:
- Baseline 6MWT distance and LV ejection fraction are independent predictors of mortality in CRT-treated CHF patients.
- A 6MWT distance <225 meters identifies patients at elevated mid-to-long-term risk of cardiovascular death.
Aims:
Cardiac resynchronization therapy (CRT) has been proven to be effective in patients suffering from chronic heart failure (CHF) associated with electrical dyssynchrony. However, long-term predictors of mortality in that subset have not been extensively investigated. The aim of this study was to establish baseline long-term predictors of cardiovascular mortality in CHF patients treated with CRT.
Methods And Results:
A total of 188 consecutive patients with moderate to severe CHF who had undergone a successful CRT implant were evaluated. Baseline measurements included clinical history, a 6-min walking test (6MWT), and echocardiographic parameters. Patients with cardiac or non-cardiac diseases limiting their ability to perform a 6MWT were excluded, with the final count totalling 155 patients [82% men, mean age 69 +/- 8 years, New York Heart Association (NYHA) functional class: II 22%, III 73.5%, IV 4.5%]. A total of 24 patients (15.5%) died of cardiovascular causes and one patient underwent heart transplantation during a mean follow-up of 24.4 +/- 18.1 months. Univariate analysis showed that NYHA class, distance walked in the 6MWT, left atrial diameter, digoxine and left ventricle (LV) ejection fraction were all significantly related to rates of mortality. Multivariate Cox regression after adjustment for the presence of a defibrillator showed that the LV ejection fraction [HR 0.91 (95% CI: 0.84-0.98) P = 0.008] and 6MWT distance <225 m [HR 5.6 (95% CI: 1.2-25.3) P = 0.026] were independent predictors of cardiovascular mortality.
Conclusion:
Baseline functional capacity, measured by the 6MWT distance, and LV ejection fraction are independent predictors of mortality in moderate to severe CHF patients, despite CRT. A 6MWT distance walked of <225 m identifies patients at high risk of cardiovascular death at mid-long term.
