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RESEARCH PRODUCT

Clinical Benefit of Cardiac Resynchronization Therapy With a Defibrillator in Patients With an Ejection Fraction > 35% Estimated by Cardiac Magnetic Resonance

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A B S T R A C T Introduction and objectives: Cardiac resynchronization therapy with a defibrillator prolongs survival and improves quality of life in advanced heart failure. Traditionally, patients with ejection fraction > 35 estimated by echocardiography have been excluded. We assessed the prognostic impact of this therapy in a group of patients with severely depressed systolic function as assessed by echocardiography but with an ejection fraction > 35% as assessed by cardiac magnetic resonance. Methods: We analyzed consecutive patients admitted for decompensated heart failure between 2004 and 2011. The patients were in functional class II-IV, with a QRS to 120 ms, ejection fraction 35% estimated by echocardiography, and a cardiac magnetic resonance study. We included all patients (n=103) who underwent device implantation for primary prevention. Ventricular arrhythmia, all-cause mortality and readmission for heart failure were considered major cardiac events. The patients were divided into 2 groups according to systolic function assessed by magnetic resonance. Results: The 2 groups showed similar improvements in functional class and ejection fraction at 6 months. We found a nonsignificant trend toward a higher risk of all-cause mortality in patients with systolic function 35% at long-term follow-up. The presence of a pattern of necrosis identified patients with a worse prognosis for ventricular arrhythmias and mortality in both groups. Conclusions: We conclude that cardiac resynchronization therapy with a defibrillator leads to a similar clinical benefit in patients with an ejection fraction 35% or > 35% estimated by cardiac magnetic resonance. Analysis of the pattern of late gadolinium enhancement provides additional information on arrhythmic risk and long-term prognosis.