新規血管内結石破砕システムに関連するR-on-T現象近傍および心筋キャプチャ

Ventricular myocardial capture, or "shocktopics," is a known phenomenon during intravascular lithotripsy (IVL). While well documented with established systems, data on newer IVL platforms are limited. We report a case of near R-on-T phenomenon using a novel IVL system.

A 74-year-old woman underwent percutaneous coronary intervention for a severely calcified left anterior descending artery lesion. During the application of a novel IVL system (Shunmei), frequent ventricular capture was observed. Several pulses occurred late in the T wave, representing a near R-on-T phenomenon. Despite these findings, the patient remained hemodynamically stable, and no sustained arrhythmias occurred.

This case confirms that IVL-induced ventricular capture is a class effect rather than being device specific. The occurrence of near R-on-T capture highlights the potential for life-threatening arrhythmias, although the clinical course is typically benign.

Continuous electrocardiographic and hemodynamic monitoring are mandatory during IVL across all device platforms to detect myocardial capture. Operators should remain vigilant for R-on-T phenomena, which may pose a theoretical risk for malignant arrhythmias. The development of electrocardiogram-synchronized (gated) IVL delivery systems may represent a critical future step in eliminating the risk of R-on-T pulses and enhancing procedural safety.