A Study of Microcirculatory Function in Type 2 Myocardial Infarction (T2MI)

The purpose of this research is to find out if patients with Type 2 Myocardial Infarction (T2MI) without significant epicardial coronary artery disease (CAD) have a greater chance of having coronary microvascular disease (CMD).

Inclusion Criteria: * Ability to give informed consent * Structurally normal heart (normal LV and RV function, no more than mild valvular heart disease) * For controls: atypical chest pain with indication for CMD testing * For T2MI: meet criteria for T2MI according to the 4th Universal definition of MI (rise/fall of troponin with at least 1 value \>99th centile+ evidence of symptoms or signs of myocardial ischemia) Exclusion Criteria: * Acute coronary event (evidence of plaque rupture, fissure or dissection on coronary angiogram) * Known to have angiographically significant CAD/pressure wire positive for epicardial CAD * Inability to receive heparin products * Allergy/contraindication to acetylcholine/adenosine/nitroglycerine products * Prior coronary artery bypass grafting * Pregnancy (if sexually active woman of reproductive age, need negative pregnancy test prior to proceeding with coronary angiography - this is standard of care in cath lab) * Asthma with prior ICU admission due to bronchospasm/need for invasive ventilation