Can a higher dose of adenosine sharpen heart scans?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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 \<24h prior to the examination Healthy volunteers: 1. The subject has given their written consent to participate in the trial. 2. 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) 3. No caffein intake \<24h prior to the examination Exclusion Criteria: Patients: 1. Acute referral (in-house patients) 2. Clinically unstable 3. Acute chest pain 4. Severe or decompensated heart failure 5. Non sinus rhythm (e.g. atrial fibrillation) 6. Asthma or severe chronic obstructive pulmonary disease 7. Known chronic renal failure (eGFR \<45mL/min/1.73m2) 8. AV-block II or III 9. Left Bundle Branch Block 10. Systolic blood pressure \<90 mmHg or \>230 mmHg at rest 11. Increased intracranial pressure 12. Known allergy or adverse reaction to adenosine or mannitol 13. Known allergy or adverse reaction to gadolinium contrast agents 14. Treatment with medication containing dipyradimol or teofyllamin/teofyllin 15. Claustrophobia 16. Devices contraindicated to CMR imaging (pacemaker, implants, intracranial clips etc) 17. Pregnancy or breast feeding (screened by question only) 18. Inability to give informed consent due to mental state, language difficulties etc Healthy volunteers: 1. Any of the exclusion criteria for patients 2. Blood pressure \> 140/90 measured according to clinical routine 3. Known systemic disease 4. Known cardiac disease 5. Cardiovascular medication 6. Medication that might influence cardiovascular health 7. Smoking