Fig. 1

Study Protocol. Patients were recruited between staged coronary interventions or the initial diagnostic angiography and surgical revascularization therapy. After primary angiography, QCA of all vessels was performed and patients were recruited if there was at least one untreated vessel with a significant lesion (diameter stenosis; DS > 50%). For oxygen sensitive cardiovascular magnetic resonance (OS-CMR), a rest image was obtained during a short breath-hold. Participants then hyperventilated for 60s (30 breaths per minute, paced by a metronome), controlled through qualitative capnography with visual confirmation of sufficient respiratory excursions. This was immediately followed by a long breath-hold, which was imaged throughout its entire duration with repetitive OS measurements (grey boxes). Quality control of apnea also included monitoring for absence of exhaled carbon dioxide with capnography and breathing motion artifacts in the images