Catheter induced ectopy
Catheter induced ectopy is due to irritation of the local endocardium and will show all the features of a target ventricular ectopic for ablation: QS complexes in unipolar recordings, onset of QRS in the unipolar distal lead and the bipolar distal lead of the ablation catheter preceding the QRS in other leads. But this site should not be targeted for ablation. Only spontaneously occurring ectopics with the same features should be targeted for ablation.
Catheter induced ectopy also causes problem in interpreting mitral regurgitation. While taking a left ventriculogram to assess mitral regurgitation, the catheter should be in the mid cavity to avoid ectopy as far as possible.
Catheter induced ectopy is sometimes useful to terminate a tachycardia which occurs in the course of an electrophysiological study or a cath study.
Post ectopic potentiation is another phenomenon which can be associated with catheter induced ectopy, just like any other ectopy.