September 2022: Acute Coronary Syndrome Logic

Show Notes: First ask, "Are you having pain now?" If your patient answers no, consider this unstable angina until proven otherwise even if the pain went away with an antacid. Antacids relieve pain in about 15 percent of ACS. Why? Coincidence. The real lesson here is that the percentage of acute coronary syndrome that presents as unstable angina is probably 15 percent at a minimum. It's actually probably at least twice that because not everyone tries an antacid. If you are looking for unstable angina, you are less likely to be fooled by false-negative troponins. This is still true of high-sensitivity troponin, although supposedly some literature says it can rule out unstable angina if the level is below the level of detection at least three hours out from peak pain and presentation. It has to be better than normal; it has to be undetectable.   Second Troponin v. Second History: I would like to be spread the following lesson to everyone in EM: "Before you do a second troponin, do a second history!" You need to really nail down the timing and duration of symptoms the best you can or you may be misled. Some patients speak their own language: "Constant" can mean "frequent." Most of us already know that "no medical problems" can mean "no untreated medical problems" to a lot of people. It is safest to start with the assumption that all chest pain is unstable angina until proven otherwise, that the pain is episodic lasting five to 10 minutes, and that the troponin and ECG may both be useless.   HEART Score Logic: The HEART score is super useful and can help protect you if you send the wrong patient home, but you should still try to avoid doing that. The HEART score's major blind spot is unstable angina because the troponin and ECG may be normal if pain lasts less than 20 to 30 minutes. Another caveat of the HEART score is grouping together all the patients with scores from 0-3. If the risk of this group is about one to two percent on average, logic dictates that patients with a score of 0-1 are actually at lower risk, but those with a score of 2-3 are likely at higher risk, perhaps three to four percent or even more. What is the actual risk associated with a HEART score of 3? We won't know until someone does the study, but risk jumps to 10 to 20 percent once you hit the 4-6 score group. If you extrapolate the data, the risk of a MACE at 30 days is probably two to three times the HEART score, so for 3 it would be nine percent, if you use logic.   Back to the question, "Are you having pain now?" If your patient answers yes, your next question should be, "When did the current episode start?" Or better yet, "When was the last time you had no discomfort?" If it was less than two hours earlier, you should be doing serial ECGs every 30 minutes if you can, so you don't miss a STEMI with an initially nondiagnostic or even near-normal ECG. It can take two hours or even more for ST elevation to manifest in some cases. You want that to be picked up early, not eight hours later when your patient is on the floor and it is too late for cath to help much.