Hyperemic mYocardial Perfusion by adEnosine at diffeRent Doses

Adenosine is a commonly used pharmaceutical stressor at cardiac magnetic resonance examinations to assess suspected chronic coronary syndrome (CCS). However, several studies have reported that the current use of adenosine does not induce adequate hyperemic response in a substantial number of patients, leading to false diagnostics. The aim of this trial is to investigate the hyperemic effect of the standard dose of adenosine (140 microgram/kg/min) to the high dose of adenosine (210 microgram/kg/min) to improve the diagnostic methods using adenosine as a stressor and ultimately improve treatment decisions and patient prognosis in CCS.

Inclusion Criteria: Patients: 1. The subject has given their written consent to participate in the trial. 2. Are referred to Department of Clinical Physiology, Skåne University Hospital, for suspected or known CCS or heart failure 3. Matches the inclusion criteria for sex and age (6 females and 6 males from each group in each age decade from 40 to \>80 years old) 4. Matches the inclusion criteria for no known heart failure (group b) or known heart failure (group c) 5. No caffein intake \80 years old) 3. No caffein intake \