Patients with atrial septal defect had lower resting stroke work (p<0.001) than controls, but both groups increased contractility during dobutamine stress (p<0.001).
Case-Control (n=34)
Does dobutamine stress reveal differences in left-ventricular haemodynamic response assessed by CMR-based PV loops in patients with atrial septal defect compared to healthy controls?
Noninvasive PV loops derived from CMR and brachial blood pressure demonstrate that patients with ASD have normal LV energy efficiency and can increase contractility during stress, despite lower baseline stroke work compared to controls.
BACKGROUND: Atrial septal defect (ASD) results in a left-to-right shunt causing right-ventricular (RV) volume overload and decreased cardiac output from the left ventricle. Pressure-volume (PV) loops enable comprehensive assessment of ventricular function and might increase understanding of the pathophysiology of ASD. The aim of this study was to investigate if left-ventricular (LV) haemodynamic response to stress in patients with ASD differs from controls. MATERIAL AND METHODS: Patients with ASD (n = 18, age 51 ± 18) and healthy controls (n = 16, age 35 ± 13) underwent cardiac magnetic resonance (CMR) and brachial cuff pressure measurements at rest and during dobutamine stress. An in-house, validated method was used to compute PV loops. RESULTS: Patients had lower stroke work, potential energy and external power at rest than controls (p < 0.001; p < 0.05; p < 0.05). Stroke work and external power increased and potential energy decreased during stress in patients (p < 0.05; p < 0.0001; p < 0.01) and controls (p < 0.0001; p < 0.001; p < 0.01). Contractility and arterial elastance at rest were higher in patients than controls (p < 0.01; p < 0.01). Contractility increased during stress in both groups (p < 0.0001; p < 0.001). There was no difference between patients and controls in arterio-ventricular coupling. CONCLUSION: 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.
Sjöberg et al. (Fri,) conducted a case-control in Atrial septal defect (n=34). Atrial septal defect vs. Healthy controls was evaluated on Left-ventricular haemodynamic response to stress. Patients with atrial septal defect had lower resting stroke work (p<0.001) than controls, but both groups increased contractility during dobutamine stress (p<0.001).