16-lead ECG changes with coronary angioplasty. Location of ST-T changes with balloon occlusion of five arterial perfusion beds.

Percutaneous transluminal coronary angioplasty (PTCA) occlusion in five individual coronary artery distributions produced significant ST elevation ("current of injury") in 48/50 PTCAs in 46 patients. Four patients had PTCA of two separate coronary arteries. Two patients had no significant ischemic ST changes in the 16 simultaneous lead ECG and no chest pain with PTCA. The six limb leads were recorded from Mason-Likar locations modified by moving them centrally on the anterior torso; the V leads were recorded in standard locations, except V1 was moved to V3R. Four extra leads were placed as follows: (1) left axilla, (2) left subcostal margin, (3) V8, and (4) midback at the level of V4-V8. The left axillary and back leads discriminated diagonal and left circumflex (LCX) PTCAs from the others and from each other. V6 showed ST elevation in all LCX PTCAs and in only 10% of left anterior descending occlusions. V3R showed ST elevation in 82% of right coronary PTCAs. In 48/50 (96%) of PTCA occlusions the ST elevation was localized to the torso locations defined in Forward Model Simulations as specific for the arterial perfusion bed involved. These data strongly support the hypothesis that additional resolution and sensitivity to ischemic change is to be expected with a broader array of ECG leads.