At other times in the tracing, the PR interval is normal and the QRS complexes are narrow. ... the tracing may simulate either ventricular bigeminy or electrical alternans.

Unlike premature atrial contractions, or PACs, usually narrow-complexed because they use the normal ventricular conduction system (unless a baseline right or left bundle branch block is present).

The initial three quarters of the tracing in Figure 1 could be either ventricular bigeminy with a pseudo-delta wave or ventricular preexcitation of every other beat. Luckily, the last three beats ...

The regular arrhythmia occurring at the beginning of the electrocardiogram was identified as ventricular bigeminy. Single ventricular premature complexes (VPCs), as well as pairs and triplets of ...