An elderly person collapsed and was found to be pulseless. He had immediate bystander CPR. An AED was placed and one shock was given within 5 minutes of arrest. He immediately awoke. EMS arrived and recorded these ECGs:
Time = 0
|Sinus rhythm. Inferior and lateral ST elevation, with hyperacute T-waves in V4-V6.|
|No definite difference.|
He was stable en route to the ED. On arrival, he was awake and complained of only mild aching left chest pain. He stated that prior to his collapse, he had been walking briskly and was feeling short of breath, but not having any chest pain. He does have a history of CAD with a stent, and takes clopidogrel, but he did not take it on this particular day.
He had this ED ECG recorded, 13 min after first
|There is inferior ST elevation with reciprocal ST depression in aVL, diagnostic of inferior injury. The hyperacute T-waves in V4-V6 are diminished and there is less ST elevation.|
The cath lab was activated. He was given aspirin and heparin.
Prior to transport, another ECG was recorded. This one is 25 min after first prehospital, and 12 min after the first ED ECG:
|There is nearly complete resolution of all injury pattern|
Angiogram showed no culprit, but did show severe 3 vessel disease, with 100% chronic LAD and RCA occlusions, and chronic 75% circumflex. All territories were supplied by collaterals from the circumflex!
An immediate Echo showed distal inferior and distal septal, anterior, and apical wall motion abnormality, with EF of 55-60%.
The patient was prepared for CABG.
Here is an ECG 15 hours after first:
|Some reperfusion T-wave inversion in V5 and V6.|
Troponin I peaked at 0.59 ng/mL.
ECG recorded 24 hours after first
|More pronounced reperfusion waves in V3-V6 (Lateral Wellens' waves)|
The patient underwent successful CABG.
Here is an ECG recorded after CABG:
|There was some inferior injury that occurred from bypass. This is not unusual.|
So what happened?
1. The patient had demand ischemia from walking with severely restricted coronary flow.
2. The ischemia resulted in ventricular fibrillation.
3. The extreme low flow state of arrest, along with extremely poor coronary flow after resuscitation, resulted in transmural ischemia (subepicardial ischemia) with ST elevation and hyperacute T-waves.
So this is Type 2 MI with ST elevation (we avoid the term "type 2 STEMI", as STEMI is a term associated with ACS)