How Many PVCs Occur in a Row in Unifocal Trigeminy?

Unifocal trigeminy is a rhythm disorder where every third heartbeat is a premature ventricular contraction (PVC) in a patient with an underlying normal sinus rhythm. This unique pattern involves two regular heartbeats followed by one PVC, with no consecutive PVCs occurring.

To determine the total number of PVCs over a series of heartbeats, you would count every third beat as a PVC. For example, if you observe 60 heartbeats, there would be 20 PVCs in total.

These PVCs are considered unifocal as they originate from the same location in the ventricles, presenting with the same shape on an electrocardiogram (ECG). The ECG would show a normal P wave and QRS complex for the sinus beats, while the PVCs would exhibit an abnormal QRS complex that is premature and wider than the normal complexes.

Since only a single PVC follows two regular heartbeats in trigeminy, no PVCs occur consecutively in a row. The PVCs are always separated by a pair of normal sinus beats, maintaining the pattern of two normal beats followed by one PVC.