Endothelial dysfunction in patients with non-ischemic heart disease, which has been observed in the coronary circulation [
1] as well as in systemic arteries [
2,
3], is associated with myocardial inflammatory immune responses. Other groups have demonstrated endothelial dysfunction in systemic infections, like after thyphoid vaccination [
4], Kawasaki disease [
5], in systemic vasculitis [
6] and in association with elevated CRP-levels [
7]. In the Framingham Offspring Study with 2701 patients, an association between systemic inflammation and endothelial dysfunction was confirmed [
8]. Endothelial dysfunction may determine prognosis, as has been demonstrated for patients with atherosclerosis [
9‐
11] and after transplantation [
12]. Non-invasive measurement of endothelial dysfunction is preferred to invasive measurements. However, the link between peripheral endothelial dysfunction and non-ischemic heart disease, needs to be determined. Inflammatory parameters have been associated with an increased risk of cardiovascular events [
13,
14] or the progression of heart failure [
15], similar to the observations for endothelial function. Therefore, we consider circulating cytokines a potential link between non-ischemic heart disease and peripheral endothelial dysfunction. Heart failure itself is associated with endothelial dysfunction [
16‐
19] as well as with changes in the pattern of circulating cytokines [
20,
21], however endothelial dysfunction of peripheral arteries is also observed in patients with non-ischemic heart disease and only mildly or regionally impaired left ventricular function. The aim of this study was to elucidate the relation between non-ischemic heart disease (in the absence of heart failure) and endothelial dysfunction in the peripheral circulation, considering circulating cytokines potential candidates for a link.