ASD and VSD Flow Dynamics and Anesthetic Management
Atrial septal defects and ventricular septal defects are often encountered in patients presenting for treatment under anesthesia. The flow mechanisms for both defects are predominantly left to right shunting prior to long-term maladaptive changes that may occur. Close examination of the shunt dynamics demonstrates a minor right to left shunt that occurs as well. The article discusses these dynamics and the impact on an anesthetic plan.Abstract
The figure depicts the direction and relative magnitude of shunt flow. Increasing values in the y axis indicate flow from left to right, whereas negative values indicate flow from right to left. Notice the primary left to right shunt occurs during late ventricular systole with a secondary increase during atrial contraction. The right to left shunting occurs in a double-bump fashion during rapid ventricular filling and the period just after the mitral valve closes before ventricular contraction begins.
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