Original Article

Incidence of Left Ventricular Function Improvement After Primary Prevention ICD Implantation for Non-Ischemic Dilated Cardiomyopathy: A Multicenter Experience

Atul Verma^1,*, Zaev Wulffhart¹, Dhanunjaya Lakkireddy², Yaariv Khaykin¹, Alexander Kaplan¹, Bradley Sarak¹, Mazda Biria², Jayasree Pillarisetti², Pradeep Bhat³, Luigi DiBiase⁴, Otto Constantini³, Kara Quan³, Andrea Natale⁴

¹ Southlake Regional Health Centre, Canada;
² University of Kansas Medical Center, Canada;
³ MetroHealth Campus, Case Western Reserve University, United States;
⁴ St. David’s Medical Center, Canada

Correspondence to: Atul Verma, Cardiology, Southlake Regional Health Centre, 105-712 Davis Drive, Newmarket, L3Y8C3, Canada; atul.verma{at}utoronto.ca

Accepted 20 October 2009

Objective: We sought to assess the incidence of LV function improvement in patients receiving primary prevention ICDs for NIDCM.

Methods: All NICM patients receiving primary prevention ICDs (non-CRT) from 2005-present at our institutions were studied. Patients had NIDCM confirmed by a lack of significant stenoses on coronary angiography, a lack of valvular abnormalities on echo, and LV dysfunction with EF<35%. Patients had to have a diagnosis of NIDCM for >9 months and be on optimal medical therapy for >3 months prior to implant. All patients had >NYHA II symptoms. Baseline and follow-up EF was documented by quantitative echo and/or MUGA scan.

Results: 332 patients were identified via a database search. Patients were 67±11 years, 75% male, NYHA 2.3±0.7, with EF 25±13%, and LV diastolic diameter 61±10 mm. Time from initial NIDCM diagnosis to implant was 11±6 months and duration of medical therapy pre-implant was 8±5 months. Therapy at the time of implant included ACE-inhibitors or ARBs (85%), beta-blockers (77%), spironolactone (53%), loop diuretic (63%), and digoxin (50%). Repeat EF assessment was available in 309/332 (93%) 8±6 months post-implant. EF improved to >35% in 37/309 (12%) patients. Patients who improved had a shorter time from diagnosis to implant (9±3 vs 13±5 months respectively, p=0.03). No other predictors were identified for patients with improved EF.

Conclusions: A substantial number of patients (12%) with NIDCM experience improvement in LV function to above levels recommended for ICD implant. A shorter time from diagnosis to implant may predict post-implant improvement.

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