Objective: Because most daily activities are conducted at submaximal exercise level, treatments are implemented to improve submaximal coronary artery blood flow (CABF). We sought to validate the reproducibility of cardiovascular magnetic resonance imaging measurements of submaximal CABF.
Methods: We measured CABF in the left anterior descending artery in 11 healthy postmenopausal women at rest and after submaximal bike exercise on 2 occasions 8 to 16 weeks apart.
Results: After exercise, CABF increased by 42% and 47% on the first and second examination, respectively. These changes in CABF in the 2 examinations were highly correlated (r=0.86).
Conclusions: These data indicate that cardiovascular magnetic resonance assessments of CABF before and after submaximal exercise are feasible, reproducible, and consistent with those obtained invasively. In future studies, 24 patients would be needed per group to detect a 20% change of submaximal exercise blood flow at 80% power.