Viability assessment remains a clinical challenge in patient with coronary artery disease and left ventricular dysfunction. Several imaging modalities are available for evaluating myocardial viability, based either on perfusion or on contractile reserve analysis. Briefly, perfusion analysis is highly sensitive and contractile reserve highly specific. A combined analysis of both perfusion and contractile reserve has been proposed to improve the diagnostic accuracy in patient referred for a revascularization procedure. However, the value of this combined analysis has not been validated in unselected patients referred for viability assessment.

The patients enrolled in the study will undergo a nitrate enhanced rest gated SPECT using a Tc-99m labeled tracer (sestamibi or tetrofosmine) followed by a second gated SPECT acquired during a low-dose dobutamine infusion (10 mcg/kg/mn). All patients will have a 6-month clinical and imaging follow-up, including physical examination and a nitrate enhanced rest gated SPECT using the same radiopharmaceutical. All treatments received during this 6-month period will be recorded, including medical therapy and coronary revascularization (angioplasty, stenting and CABG).

Finally, the value of baseline perfusion and contractile reserve analysis in predicting left ventricular ejection fraction changes at 6-month follow-up will be evaluated.

Inclusion Criteria:

• Documented coronary artery disease
• Left ventricular dysfunction (LVEF < 50%)
• Patients referred to the Nuclear Medicine department for myocardial viability assessment
• Sinus Rhythm
• Acceptance of a 6-month follow-up
• Signed informed consent

Exclusion Criteria:

• Recent acute coronary syndrome (< 21 days)
• Atrial Fibrillation or significant arrhythmias
• Implanted pacemaker
• Contra indication to dobutamine
• Non ischaemic cardiomyopathy
• Pregnancy

The study population consists with patients with documented coronary artery disease and left ventricular dysfunction (LVEF < 50%)referred to aNuclear Medicine department for myocardial viability assessment