HPI: 54 yo F with history of CAD s/p 4 previous stents (LAD and first diagonal branch) who presents with abdominal pain, nausea, and vomiting

EKG Interpretation: ST elevation (STE) in anterior, inferior with right ventricular extension, posterior, +/- lateral distributions (only elevation in V6). Reciprocal changes (ST depression) in leads I and aVL.

Cath Report: 100% occlusion of the RCA. 100% occlusion of the posterolateral subdivision. 50% in-stent restenosis of the mid LAD. 50% stenosis of the first diagonal branch

Procedure: Aspiration thrombectomy, PCI of distal and mid RCA x 2

Commentary:

-AHA/ACC for STEMI: Men < 40: 2.5 mm (2.5 small EKG boxes) ST-elevation in V2 or V3, 1 mm in any other lead, Men > 40: 2.0 mm ST-elevation in V2 or V3, 1 mm in any other lead, Women: >1.5 mm ST-elevation in V2 or V3, 1 mm in any other lead

-Leads and Vessel Correlation: V1-V4 are anterior/septal leads correlate with the Left Anterior Descending artery. II, III, and aVF are inferior leads correlate with the Right Coronary artery. I, aVL, V5-V6 are lateral leads correlate with Left Circumflex artery

-Posterior MI: Present if ST depression in the right precordial leads or presence of prominent R-waves and upright T-waves in these same leads. Accompanies 15-20% of STEMIs. Usually associated with inferior or lateral infarctions. Suggestive of a much larger area of myocardial damage. Can consider a posterior EKG to look for STE (V7-V9 in horizontal plane underneath the left scapula)

-Right Ventricular Infarction: Present if the magnitude of ST-segment elevation in lead V1 exceeds the magnitude of ST-segment elevation in lead V2, or if the ST-segment in lead V1 is isoelectric and the ST-segment in lead V2 is significantly depressed, or if the magnitude of ST-segment elevation in lead III exceeds the magnitude of ST-segment elevation in lead II. Associated with approximately 40% of inferior STEMIs. Patients tend to be very preload sensitive from poor RV contractility and nitrates are contraindicated. Consider EKG with right sided leads to look for STE (transfer V3-V6 to right side of chest)

Check out this recent lecture from Dr Stephen Smith of the famous ECG Blog. The link is to a google doc but it is still live after months. He describes some sophisticated ST segment and T wave changes that ER doctors must know to pick up subtle ischemia. You have to just love how Smith is so candid about his opinions. He does not mess around with anyone who argues with the Occlusion MI (OMI) paradigm or even individual tracings. He says that sadly some people just can’t see the subtle findings, but I maintain hope that every studious ER doc can master the image pattern recognition he teaches. And if they can’t, maybe AI can. Smith advises multiple companies that use AI to detect these subtle ECG findings, to determine when patients are having OMIs. His software appears to be quite effective.

Something to keep in mind while watching, he is going over (tons of) cases that all have a relatively high pretest probability of ischemia. He has selected them out. We are working on evaluating and treating more ‘cardiac patients’ at ULH, but his patient population (at Hennepin) would be more like Jewish or maybe even other centers in town with more active cath labs.

A few of the rules that came up repeatedly in the video:

Smith of course talks about the weakness of a STEMI/NSTEMI paradigm, arguing instead for the occlusion MI paradigm.

Proportionality, proportionality, proportionality – T wave size in proportion to the QRS. A medium sized broad T wave after a tiny QRS is concerning!

Similarly, the morphology of the Hyperacute T is usualy broad based, and not tall and peaked like hyperK+. Thus, thinking about the area under the curve of the T wave makes more sense.

Biphasic T waves (down up meaning recip change) – we usually talk about biphasic reperfusion T waves in the leads involved in ischemia, but here mostly shows biphasic T waves reciprocal to infarction pattern in other leads.