The aim of the present study is to investigate whether the ingestion of a flavonoid-rich dark chocolate compared to flavonoid-free placebo chocolate will improve coronary vasomotion in heart transplanted patients.

Dark chocolate contains a high amount of flavonoids. Flavonoids hold the possibilities to improve oxidative stress and hence the possibility to improve endothelium-dependent coronary vasomotion, which is a powerful surrogate for clinical prognosis. Coronary atherosclerosis is promoted by impaired endothelial function and increased platelet activation. High oxidative stress and reduced antioxidant defenses play a crucial role in the pathogenesis of atherosclerosis, in particular in transplanted hearts. The aim of the present study is to investigate whether the ingestion of a flavonoid-rich dark chocolate compared to flavonoid-free placebo chocolate will improve coronary vasomotion in heart transplanted patients.

Inclusion Criteria:

1. Patients after heart transplantation not requiring immediate coronary intervention
2. Age 20 - 80
3. Written obtained informed consent

Exclusion Criteria:

1. Heart failure (acute or chronic >NYHA II)
2. Ventricular tachy-arrythmias or AV-Block >I°
3. Renal insufficiency (>200 μmol/l) or liver disease (ALT or AST >150 IU)
4. Symptomatic hypotension, hypertension >160/100mmHg
5. Known allergy to compounds dark chocolate
6. Acute infectious disease
7. Disease with systemic inflammation (e.g. rheumatoid arthritis, M. Crohn)
8. Participation in another study within the last month
9. Concomitant vitamin supplements