Incidence of "shocktopics" and asynchronous cardiac pacing in patients undergoing coronary intravascular lithotripsy

Aims: Coronary intravascular lithotripsy (IVL) is a novel approach to vascular calcium modification that restores vessel compliance allowing effective lesion expansion. In this study we report the capacity for coronary IVL to precipitate ventricular ectopics ("shocktopics") and asynchronous cardiac pacing. Methods and results: This was a retrospective review of all cases of coronary IVL (n=54) undertaken in the Royal Victoria Hospital, Belfast, between September 2018 and March 2019. The indication for PCI was chronic stable angina in 46.1% (n=26), non-ST-elevation acute coronary syndrome (NSTEACS) in 33.3% (n=18) and ST-elevation myocardial infarction (STEMI) in 18.5% (n=10) of patients. The incidence of coronary IVL-provoked ventricular capture was 77.8% (n=42). Multivariable logistic regression analysis identified heart rate as the only independent predictor of an increased risk of IVL-induced ventricular capture. Patients with a heart rate <65 bpm prior to IVL were sixteen-fold more likely (OR 16.3 [2.4-110.8], p=0.004) to experience events compared to patients with a heart rate ≥65 bpm. "Shocktopic" beat morphology was largely uniform in each patient and appeared dependent on the target lesion location, in keeping with mechano-electric coupling through activation of local stretch-activated cardiomyocyte channels. No adverse clinical events occurred as a result of coronary IVL-induced capture. Conclusions: Coronary IVL with the Shockwave Medical system is associated with a high incidence of "shocktopics" and asynchronous cardiac pacing that is largely dependent on the resting heart rate. There have been no clinical events associated with this phenomenon, but further systematic evaluation is warranted.