Reduced regional myocardial perfusion reserve is associated with impaired contractile performance in idiopathic dilated cardiomyopathy

Abstract

Background. In idiopathic dilated cardiomyopathy (IDC) an imbalance between myocardial oxygen consumption and supply has been postulated. Subclinical myocardial ischaemia may contribute to progressive deterioration of left ventricular function. The relation between regional myocardial perfusion reserve (MPR) and contractile performance was investigated.Methods. Patients with newly diagnosed IDC underwent positron emission tomography (PET) scanning using both (13)N-ammonia as a perfusion tracer (baseline and dypiridamole stress), and (18)F-fluorodeoxyglucose viability tracer and a dobutamine stress MRI. MPR (assessed by PET) as well as wall motion score (WMS, assessed by MRI) were evaluated in a 17-segment model.Results. Twenty-two patients were included (age 49+/-11 years; 15 males, LVEF 33+/-10%). With MRI, a total of 305 segments could be analysed. Wall motion abnormalities at rest were present in 127 (35.5%) segments and in 103 (29.9%) during dobutamine stress. Twenty-one segments deteriorated during stress and 43 improved. MPR was significantly higher in those segments that improved, compared with those that did not change or were impaired during stress (1.87+/-0.04 vs. 1.56+/- 0.07 p<0.01.)Conclusion. Signs of regional ischaemia were clearly present in IDC patients. Ischaemic regions displayed impaired contractility during stress. This suggests that impaired oxygen supply contributes to cardiac dysfunction in IDC. (Neth Heart J 2009;17:470-4.).

Keywords: cardiac magnetic resonance imaging; endothelial function; idiopathic dilated cardiomyopathy; ischaemia; positron emission tomography.

Figure 1

Relation between global myocardial perfusion reserve as measured with PET and the summed difference score (SDS) with dobutamine stress (p=0.029).

Figure 2

Myocardial perfusion reserve (MPR) assessed with PET (rest-dipyridamole ¹³N-ammonia stress) in myocardial segments with and without wall motion deterioration during dobutamine stress MRI. *p<0.01.