Dobutamine stress in patients with atrial septal defects significantly decreased the pulmonary to systemic flow ratio from 2.0 at rest to 1.5 (P<0.001).
Observational (n=42)
Does dobutamine stress alter left-to-right shunting and correlate with exercise capacity in patients with secundum ASD?
Dobutamine stress in ASD patients decreases the pulmonary to systemic flow ratio and shunt volume per heartbeat, with systemic cardiac output during stress strongly predicting exercise capacity.
Tasa de eventos absoluta: 1.5% vs 2%
valor p: p=<0.001
BACKGROUND: The purpose of this study was to determine the effect of stress on left-to-right shunting in patients with atrial septal defect (ASD) and to investigate if the degree of shunting, cardiac output (CO), and right ventricular (RV) volumes are related to exercise capacity. METHODS: Twenty-six patients with a secundum ASD and 16 healthy volunteers were studied with rest/stress cardiac magnetic resonance using 20 µg/kg/min dobutamine and 0.25-0.75 mg atropine to quantify CO, pulmonary to systemic flow ratio (QP/QS), and left ventricular (LV) and RV volumes. Peak oxygen uptake (VO2peak) was determined on ergospirometry. RESULTS: In patients with ASD the QP/QS decreased from 2.0 ± 0.2 at rest to 1.5 ± 0.1 (P < 0.001) during dobutamine stress (n = 20) and shunt volume per heartbeat decreased from 70 ± 9 to 38 ± 9 mL (P < 0.001). However, absolute shunt volume per minute was unchanged (5.1 ± 0.8 vs. 4.5 ± 1.0 L/min, P = 0.32) explained by a higher increase in systemic CO during stress (90 ± 11%) compared with pulmonary CO (43 ± 7%, P < 0.001). In ASD patients, VO2peak correlated with aortic CO during stress (r = 0.77) and QP/QS at rest (r = -0.48) but not during stress (P = 0.09). VO2peak did not correlate with RV volumes in patients. CONCLUSION: Pulmonary to systemic flow ratio and shunt volume per heartbeat decrease during stress in ASD patients. This may be explained by an enhanced LV diastolic function during stress and may have implications to detect disturbances in LV compliance in ASD patients. A high systemic CO during stress is a strong predictor of exercise capacity.
Stephensen et al. (Thu,) conducted a observational in Atrial septal defect (n=42). Dobutamine stress vs. Rest was evaluated on Pulmonary to systemic flow ratio (QP/QS) (p=<0.001). Dobutamine stress in patients with atrial septal defects significantly decreased the pulmonary to systemic flow ratio from 2.0 at rest to 1.5 (P<0.001).
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