Dobutamine Stress Echocardiography in Cardiac Resynchronization Therapy (CRT) Patients Selection (LODO-CRT)

While cardiac resynchronization therapy (CRT) has a well demonstrated therapeutic effect in selected patients with advanced heart failure (HF) on optimized drug therapy, non-responder rate remains high. The low-dose dobutamine stress-echo (DSE) test to predict positive response to CRT (LODO-CRT) trial is designed to improve patient selection for CRT.

LODO-CRT is a multicenter prospective study enrolling HF patients with conventional indication to CRT (symptomatic stable NYHA class III-IV on optimized drug therapy, QRS≥120 msec, left ventricular (LV) dilatation, LVEF≤35%) is designed to assess the predictive value of LV contractile reserve (LVCR), determined through DSE, in predicting CRT response during follow-up. Assessment of CRT effects will follow two sequential phases: in phase 1 CRT response end-point is defined as left ventricular end-systolic volume (LVESV) reduction ≥ 10% at 6 months; in phase 2, both LVESV reduction and clinical status via a clinical composite score will be evaluated at 12 months follow-up. Predictive value of LVCR will be compared to other measures, such as LV dyssynchrony measures, through adjusted multivariable analysis. For the purpose of the study, target patient number is 270 patients (with 95% confidence, 80% power, α≤0.05).

LVCR assessment, using low-dose DES test, should effectively predict positive response to CRT both in terms of the reverse remodeling process as well as favorable long-term clinical outcome. Moreover, the predictive value of LVCR will be compared to that of conventional intra-LV dyssynchrony measures.

Patient indicated to CRT according to current guidelines

Inclusion Criteria:

• severe HF despite optimized medical therapy
• NYHA functional class III-IV
• dilated cardiomyopathy of both ischemic and non-ischemic origin
• left ventricular ejection fraction (LVEF) <=35%
• QRS complex duration ≥120 ms
• normal sinus rhythm.

Exclusion Criteria:

• younger than 18 years old
• unstable angina
• acute myocardial infarction
• coronary artery bypass graft (CABG) or percutaneous transluminal coronary angioplasty (PTCA) within the past 3 months
• already implanted with a conventional implantable pulse generator or with an implantable cardioverter defibrillator (ICD)
• previously implanted with a CRT device
• chronic permanent atrial arrhythmias