Haemodynamic left-ventricular changes during dobutamine stress in patients with atrial septal defect assessed with magnetic resonance imaging-based pressure-volume loops.

LV haemodynamic response to stress can be assessed using noninvasive PV loops derived from CMR and brachial blood pressure. Patients with ASD had normal LV energy efficiency, in contrast to other patient groups with decreased cardiac output. Data suggest that patients with ASD had an increased inotropic level at rest with high contractility and heart rate but were able to respond with a further increase during stress, albeit to not as high a cardiac output as controls.