Monitoring of ischemia during percutaneous coronary angioplasty: influence of guidewire, balloon placement, and lead selection.

We examined the sensitivity of the surface 12-lead electrocardiogram (ECG) for detecting ischemia during guidewire and deflated balloon passage as well as during balloon inflation in proximal epicardial stenoses during percutaneous transluminal coronary angioplasty (PTCA) of 55 patients. Ischemia (ST change greater than or equal to 0.1 mV) by 12-lead ECG was detected in 28% of patients after guidewire passage, in 50% after deflated balloon passage, and in 76% during balloon inflation vs. 17%, 14%, and 50%, respectively, by limb lead monitoring alone. The best single lead for detecting ischemia during PTCA was V2 for left anterior descending and circumflex and III for right coronary artery inflations. The addition of a selected second precordial lead further enhanced ischemia monitoring. We conclude that ischemia is common during PTCA even during wire and deflated balloon passage, that the 12-lead ECG is more sensitive for monitoring ischemia during PTCA than conventional techniques, and that laboratories can optimize their ability to detect ischemia during PTCA by selecting appropriate leads.