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Figure 4 Illustration of acute ST-segment changes and spontaneous ST-segment elevation myocardial infarction as recorded by implanted medical device. Tracings were obtained from telemetry from implantable cardiac device to external alerting device. (A) Shows stable normal sinus rhythm without ST-segment shift at baseline 26 h after medical device implant. (B) ST-segment elevation is noted after 90 s of balloon inflation, during copper stent implantation in the left anterior descending coronary artery. (C) The animal developed ventricular fibrillation at  120 s into the left anterior descending coronary artery stent implant. External cardioversion/defibrillation is performed with 300 J (square wave in C), without deleterious effect on the implanted medical device. After 4 min of recovery, the intracardiac electrogram returns to baseline (D). At 3 h after copper stent implant, the electrogram shows rapid evolution to marked ST-segment elevation (72% vs. QRS amplitude, E) with emergency alert. Within 30 min from onset of ST-segment elevation myocardial infarction, the animal develops spontaneous ventricular fibrillation (F) and then expires, with a flat line tracing (G).
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