Decrease in the percentage of biventricular pacing due to frequent premature ventricular contractions

Frequent premature ventricular contractions, isolated or paired, bigeminism or trigeminism, at rest or during exercise, is a common cause of the decrease in the percentage of biventricular pacing. It also causes a relative bradycardia as the PVCs are relatively ineffective from a hemodynamic standpoint. In a CRT patient, the evolution of the frequency of PVCs should be continuously monitored since they can be prompted by metabolic disorders and induced by drugs, or be the expression of a worsening underlying heart disease, or even at the origin of clinical decompensation. In non-responder patients, suppressing the PVCs is a priority so as to allow an increase in the percentage of biventricular pacing and thus anticipate a positive response to the resynchronization therapy. Different options are possible:

1. in this patient, an increase in the minimum rate at 70 bpm eliminated the PVCs. The effect of this type of programming on the PVCs is however often incomplete or only temporarily effective. Moreover, it is occasionally necessary to program a relatively high heart rate at rest (> 80 bpm), which is difficult to accept on the long term in those patients with severe heart failure;
2. anti-arrhythmic drug therapies (beta-blockers, amiodarone) are rarely effective in this setting;
3. in the presence of monomorphic PVCs, a radiofrequency ablation procedure can be proposed. This last option is indicated in cases of impaired hemodynamic status. The evaluation of the correlation between the functional and clinical abnormalities is essential in the decision making process.