Quantitation of global and regional left ventricular function by cine magnetic resonance imaging during dobutamine stress in normal human subjects

Magnetic resonance imaging (MRI) provides high-resolution images of the heart. However, physical exercise during MRI is difficult due to space restriction and motion artefacts. To evaluate the feasibility of MRI during stress conditions, dobutamine was used as an alternative to exercise. Haemodynamics, ventricular volumes and wall thickening were measured at rest and during peak dobutamine infusion (15 μg . kg−1 . min−1) in 23 normal human subjects. To calculate left ventricular volumes, eight short-axis views were obtained encompassing the left ventricle from base to apex. At six levels, percent systolic wall thickening (% WTh) was measured in 18 segments (20° intervals). Heart rate, systolic and diastolic blood pressures, stroke index, cardiac output and left ventricular ejection fraction increased significantly during dobutamine infusion (all P values