Abnormalities in myocardial contractility, metabolism and perfusion reserve in non-stenotic coronary segments in heart failure patients.

OBJECTIVE

Myocardial blood flow (MBF) reserve is impaired in congestive heart failure (CHF), while fluorine-18-deoxyglucose (18FDG) uptake is relatively preserved. To determine whether this mismatch could be interpreted as ischemia, we performed dobutamine stress echocardiography (DSE).

METHODS

12 males with coronary artery disease (CAD) and CHF were compared with 12 controls with similar CAD but normal left ventricular (LV) function. MBF in non-infarct-related artery areas was assessed using [(13)N]ammonia positron emission tomography (PET), at rest and after dipyridamole infusion and 18FDG uptake was determined. DSE was performed with doses up to 40 microg/kg per min.

RESULTS

In areas with non-stenotic arteries MBF reserve was more impaired in CHF patients (1.6+/-0.6 vs. 2.2+/-0.5; CHF versus normal LV, respectively, P<0.05). MBF reserve was related to LV ejection fraction (r=0.6, P<0.05) and wall stress (r=-0.72, P<0.05). PET showed mismatch in 4+/-1% of the myocardium in normal LV, compared to 26+/-26% in CHF (P<0.05), coinciding with more ischemic wall motion abnormalities on DSE (21 vs. 4%; CHF versus normal LV, respectively, P<0.05).

CONCLUSIONS

In CHF, mismatch was found in areas supplied by non-stenotic coronary arteries. Corresponding areas showed ischemic wall motions on DSE. These findings suggest that the condition of CHF may play a role in perpetuating myocardial failure by inducing myocardial ischemia. Follow-up studies to investigate the ischemia-CHF relationship in time would be needed.