Difference in Long-term Clinical Outcome after Cardiac Resynchronization Therapy Between Ischemic and Non-Ischemic Etiologies of Heart Failure

¹ The Chinese University of Hong Kong, Hong Kong

^* To whom correspondence should be addressed. E-mail: cmyu{at}cuhk.edu.hk.

Accepted 1 July 2008

	Abstract

Objective: To examine the impact of heart failure (HF) etiology on long-term outcome after cardiac resynchronization therapy (CRT).

Design: Prospective cohort study.

Setting: University hospital.

Patients: One hundred and nineteen patients (44% with ischemic and 56% non-ischemic etiology) who underwent CRT.

Interventions: Clinical follow up for 39¡À24 months.

Main outcome measures: Cardiovascular mortality, HF and cardiovascular hospitalization were compared by Kaplan-Meier curves between the 2 groups, followed by Cox regression analysis for prognostic predictor(s).

Results: Forty-one (34%) patients died, in whom cardiovascular causes were identified in 32 (27%) patients. The ischemic group had a higher cardiovascular mortality (Log-rank ??2=4.293, p=0.038) and cardiovascular hospitalization (Log-rank ??2=5.123, p=0.024) when compared with the non-ischemic group, though no difference was found in HF hospitalization (Log-rank ??2=0.019, p=0.892). At 3-month, left ventricular reverse remodeling occurred in 52% of the ischemic group and 55% of the non-ischemic group (??2 =0.128, p=0.720). By Cox regression analysis, ischemic etiology and absence of reverse remodeling at 3-month were independent predictors of cardiovascular mortality (HR=2.698, p=0.032; HR=3.541, p=0.030) and cardiovascular hospitalization (HR=1.905, p=0.015; HR=2.361, p=0.004). Furthermore, these 2 factors had an incremental value in predicting cardiovascular mortality when compared with either alone (LV reverse remodeling, Log-rank ??2=10.275 vs. 6.311, p=0.05; Ischemic etiology, Log-rank ??2=10.275 vs. 4.293, p<0.05).

Conclusion: Ischemic etiology of HF is an independent predictor of higher cardiovascular mortality and hospitalization after CRT. This may implicate the progressive nature of coronary heart disease leading to a worse outcome despite similar short-term benefits of CRT.