Intracoronary electrocardiogram and wave intensity analysis unmask functional coronary microvascular dysfunction in a middle-aged woman with 'normal' coronary arteries: a case report

Angina and/or ischaemia with nonobstructive coronary arteries (ANOCA/INOCA) is common, particularly in women, and is most frequently attributable to coronary microvascular dysfunction (CMD), rather than representing a benign finding after exclusion of epicardial stenosis.

A 55-year-old woman with cardiometabolic risk factors had recurrent angina and reversible ischaemia on stress single-photon emission computed tomography. Coronary angiography showed no obstructive disease. Doppler-based coronary function testing in the left anterior descending coronary artery demonstrated reduced coronary flow velocity reserve (1.99) with normal hyperaemic microvascular resistance (1.31 mmHg·s·cm^-1), suggesting functional CMD. Wave intensity analysis showed high resting accelerating wave energy proportion without hyperaemic augmentation, and intracoronary electrocardiogram (ECG) during adenosine hyperaemia revealed ischaemic ST-segment shifts concordant with perfusion imaging.

Multimodal invasive assessment can phenotype the INOCA endotypes and provide real-time ischaemia confirmation. This case highlights the added value of combining intracoronary ECG with wave intensity analysis for real-time ischaemia verification in INOCA, supporting a shift from anatomical exclusion to integrated physiological diagnosis of CMD. Vasoreactivity testing was not performed; therefore, a coexisting vasospastic endotype was not excluded.