Background Implantation of mechanical cardiac support systems (MCSS) in patients with idiopathic dilated cardiomyopathy (IDC) may improve cardiac function and allow explantation of the device. We report of long-term effects of ventricular unloading on cardiac function, humoral anti-β1-adrenoceptor autoantibodies (A-β₁-AABs), and myocardial fibrosis.

Methods and Results Seventeen patients in New York Heart Association functional class IV with nonischemic IDC received MCSS. All had a cardiac index of <1.6 L · min⁻¹ · m⁻² of body surface area, a left ventricular ejection fraction (LVEF) of <16%, and a left ventricular internal diameter in diastole (LVIDd) of >68 mm and tested positive for A-β₁-AABs. Echocardiographic evaluation, serum tests for A-β₁-AABs, and histological assessment of myocardial fibrosis were performed before and after MCSS implantation. The mean support duration was 230±201 days. Six patients died, four were transplanted, and two are still on MCSS. Five patients with significant cardiac recovery (mean LVIDd, 54±2.3 mm; LVEF, 47±3.7%) were weaned after 160 to 794 days and are now device free for 51 to 592 days. A-β₁-AABs disappeared gradually during MCSS without increase after weaning; cardiac function and volume density of fibrosis remained normal. Nine patients’ cardiac function hardly improved during ventricular unloading.

Conclusions Cardiac function can be normalized in selected patients with end-stage IDC by MCSS. The degree of preoperative myocardial fibrosis may be an indicator for outcome; A-β₁-AABs can be used to monitor myocyte recovery. Weaning from MCSS offers an alternative to cardiac transplantation in certain patients.