When auscultating heart sounds of a patient, the clinician reports normal beats followed by few abnormal beats.An ECG reveals the following tracing.What is this consistent with?

Question

Quizplus · Accepted Answer

The compensatory pause occurs because the abnormal ventricular impulse does not enter the atrium to depolarize the SA node. The SA nodal rhythm is therefore undisturbed. When the SA node fires in its normal sequence, its P wave is obliterated by the PVC and its impulse arrives at the ventricles while they are still refractory. The ventricles are not stimulated again until the next normal SA nodal impulse arrives. Thus, the interval between the two visible P waves on either side of a PVC (see the figure) is twice the interval between two normally sequenced P waves.

When Auscultating Heart Sounds of a Patient, the Clinician Reports