A case of bifocal premature ventricular contractions exhibiting bigeminy with an alternating QRS morphology

Advances in management of premature ventricular contractions

Premature ventricular complexes (PVCs) are a common occurrence in clinical practice. The clinical presentation may range from asymptomatic to left ventricular (LV) dysfunction with congestive heart failure. The decision to suppress PVCs is largely based on the presence of symptoms, interference with other therapy (e.g., cardiac resynchronization therapy), or suspicion of PVC-mediated cardiomyopathy. Catheter ablation has emerged as a safe and effective option for the treatment of frequent PVCs. Careful attention to PVC characteristics on surface electrocardiogram has proven useful for the initial localization of the ectopic focus, which may then serve as a guide to procedural planning. The point of interest is often identified with activation mapping, and the ablation site can be further defined with pace mapping techniques. Clinical experience with PVC ablation has been successful in ≥80 % of cases, and the literature reports multiple cases of marked improvement in LV function after eradicating the culprit ectopic focus in patients with PVC-mediated cardiomyopathy.

A couplet of PVCs with different QRS morphologies arising from a single origin in the left ventricular outflow tract

A 59-year-old man with two different premature ventricular contractions (PVCs) forming a couplet underwent electrophysiological testing. Although pacing from the aorto-mitral continuity (AMC) produced an excellent pace map of one type of PVCs, a radiofrequency application within the right coronary cusp (RCC) eliminated all the PVCs. This case demonstrates that a single origin with two breakout sites in the left ventricular ostium (LVos) may result in a couplet consisting of different PVCs and preferential conduction from the RCC to AMC may also occur. These possibilities should be kept in our mind when predicting sites of origin of LVos ventricular arrhythmias.