EKG Findings of an AMI
There are three major blood vessels that can be occluded in an AMI. The right coronary artery (feeding the inferior wall) the circumflex (feeding the lateral wall) and the left anterior descending artery (feeding the anterior wall).[one_second]
With inferior wall ischemia or infarction, there is a lack of perfusion to the AV node. This classically makes the patient bradycardic. So, anytime you have a patient with chest pain and bradycardia, you have to do a 12 lead EKG looking for an AMI. NO ATROPINE! Remember atropine works by decreasing vagal tone on the heart and would not be good in this situation!
Vagal tone is driven by the vagus nerve, which, slows down the heart. It’s like a leash on a dog. If you yank on the leash, the dog becomes more dossal. If you cut the leash, the dogs runs rampant. Meaning, if you give atropine, the heart rate increases, thus increasing the need for oxygenation. This leads to bad things in a patient with an AMI.
In RCA occlusions, these patients, 25% of the time, have an infarction of their right ventricle as well. This makes them extremely preload dependent. Meaning, if you give nitroglycerin, this could drop their blood pressure rapidly. So, proceed with caution with vasodilators in patients with inferior wall infarctions. (If you are a hot shot, consider doing a right-sided EKG in a patient with an inferior wall AMI. Elevations in V4 would suggest a right ventricular AMI.)[/one_second] [one_second] [/one_second]
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