Cardiac Resynchronization Therapy in Patients With End-Stage Inotrope-Dependent Class IV Heart Failure

Although cardiac resynchronization therapy (CRT) is beneficial in patients with drug-refractory New York Heart Association (NYHA) class III/IV heart failure (HF) and left ventricular (LV) dyssynchrony, CRT efficacy is not well established in patients with more advanced HF on inotropic support. Ten patients (age 55 ± 13 years) with inotrope-dependent class IV HF (nonischemic [n = 6] and ischemic [n = 4]) received a CRT implantable cardioverter-defibrillator device. QRS duration was 153 ± 25 ms (left branch bundle block [n = 7], intraventricular conduction delay [n = 2], and QRS <120 ms [n = 1]). The indication for CRT was based on either electrocardiographic criteria (n = 9) or echocardiographic evidence of LV dyssynchrony (n = 1). Intravenous inotropic therapy consisted of dobutamine (n = 6; 4.3 ± 1.9 μg/kg/min) or milrinone (n = 4; 0.54 ± 0.19 μg/kg/min) as inpatient (n = 3) or outpatient (n = 7) therapy for 146 ± 258 days before CRT. One patient required ventilatory support before and during device implantation. All patients were alive at follow-up 1,088 ± 284 days after CRT. Three patients underwent successful orthotopic cardiac transplantation after 56, 257, and 910 days of CRT. HF improved in 9 patients to NYHA classes II (n = 5) and III (n = 4). Intravenous inotropic therapy was discontinued in 9 of 10 patients after 15 ± 14 days of CRT. LV volumes decreased (end-diastolic from 226 ± 78 to 212 ± 83 ml; p = 0.08; end-systolic from 174 ± 65 to 150 ± 78 ml; p <0.01). LV ejection fraction increased (23.5 ± 4.3% to 32.0 ± 9.1%; p <0.05). No implantable cardioverter-defibrillator shocks were recorded, and antitachycardia therapy for ventricular tachyarrhythmias was delivered in 1 patient. In conclusion, patients with end-stage inotrope-dependent NYHA class IV HF and LV dyssynchrony may respond favorably to CRT with long-term clinical benefit and improved LV function.