The Doppler Appearance of Aortic Flow with Premature Ventricular Contraction (PVC)
Among the given options regarding the Doppler appearance of aortic flow with a premature ventricular contraction (PVC), the correct statement is that a Doppler tracing in a patient with PVCs will demonstrate a lower velocity spike caused by the PVC followed by a higher velocity spike as the heart normalizes.
This is because a PVC arises from an ectopic focus within the ventricles and typically results in a less effective ventricular contraction due to the lack of coordinated atrial contraction. Since the stroke volume during a PVC is typically lower, the initial velocity spike in the aortic flow Doppler will be lower.
The subsequent beat is usually associated with a higher velocity because more time has elapsed for the ventricles to fill, and consequently, the stroke volume is increased, leading to a higher velocity spike.