NSTEMI (Subendocardial Ischemia) ECG Changes Explained, Myocardial Infarction(MI) ECG Interpretation

okay in our video series of PCG interpretation Made Easy by a six step method in this video we are going to talk about the last step ischemia and infarction in this video we are going to talk about sub endocardial ischemia and what are the ECG changes that you will see in sub endocardial ischemia in my previous video I talked about transmural ischemia ST segment elevation mi in this video we are going to talk about nstemi and sub endocardial ischemia no ischemia is the blood flow obstruction ischemia in the heart can occur as a transmural ischemia in which the whole thickness of the heart wall is affected or it can be a sub endocardial ischemia in which the inner layer of the heart muscle is affected that is called as a sub endocardial ischemia normally the blood supply of the heart is from the coronary arteries and coronary arteries enter the heart from outside towards inside therefore the innermost aspect of the heart is receiving lesser blood supply as compared to the outer aspect now whenever there is ischemia there is increased chance that the initial damage will be to the sub endocardium the innermost part of the heart now whenever these coronary arteries are blocked the first part in the heart to be affected is the sub endocardium because it is receiving lesser blood supply as compared to the outer aspect of the heart so initially there will be sub endocardial ischemia and subendocardial ischemia later on progresses to become transmural ischemia in which the whole wall of the heart is affected the entire thickness of the heart wall is affected appears different on ECG as compared to transmural ischemia and transmural ischemia we see ST segment elevations in sub-endocardial ischemia the classical Hallmark of sub-endocardial ischemia is ST segment depression now not all ST segment depressions indicate sub endocardial ischemia there are three different types of ST segment depression the first one is negative deflection ST segment depression in negative deflection ST segment depression you will see down sloping of the ST segment and remember this down sloping pattern of ST segment depression is most indicative of sub endocardial ischemia the second one is no deflection or squaring off of the ST segment in no deflection or squaring off of ST segment the whole ST segment is depressed equally the whole line horizontally comes down that is called as no deflection in which there is no sloping of the ST segment there is just deflection of the ST segment downwards that is moderately indicative of sub endocardial ischemia then comes the third one and the last one is that is the positive deflection in which the ST segment is moving upward it is sloping upward like this and remember this is least indicative of sub endocardial ischemia now remember one important thing regardless of whether the ST segment depression is mostly indicative or least indicative if the patient is having symptoms you have to treat that patient regardless of the ECG changes you will have to intervene because if you do not intervene you will lose the patient so for academic purposes for the purpose of knowledge this is good but in in real practice if the patient is having symptoms you have to treat the patient regardless of the ECG changes now let's solve this ECG if you look at lead one if you look at the P wave the pr segment and then you look at the empty segment The Entity segment is depressed there is ST segment depression over here so in lead one we have ST segment depression if you look at the lead 2 in lead to look at the P wave look at the pr segment and compare it with the ST segment the ST segment is depressed if you look at lead 3 in lead 3 we do not have any ST segment depression this is the QRS complex and it looks wide if you look at AVR EVR is not having ST segment depression although it is showing St slight ST segment elevation now remember ST segment elevation in one lead not important ST segment elevation more than one millimeter in two or more contiguous leads two or more related leads that is important as we discussed in our previous video so if one lead is showing SD segment elevation not very important if more than one lead if two or more than one leads are showing ST segment derivation that is important that should be looked for AVL AVL is showing somewhat depression but not very prominent depression if you look at avf avf is showing ST segment depression look at the PVF look at the pr segment look at the ST segment if you look at V1 no P an OST segment depression V two V three if you look at V4 there is prominent ST segment depression look at V4 look at V5 look at V6 prominent ST segment depression so this is an ECG indicating sub endocardial ischemia with ST segment depression now coming to an important point with ST segment depression T wave inversion also shows sub endocardial ischemia sometimes on ECG in the initial phase where the ischemia is developing when the blood supply is obstructed before the ECG shows changes like ST segment depressions the initial change sometimes is T wave inversion and T wave inversion must be taken seriously if the patient is having symptoms because T wave inversion indicates sub endocardial ischemia and the T wave inversion should be at least one millimeter deep one millimeter means one small box it should be present in greater than or equal to two continuous leads it should be present in two or more leads it should be dynamic if the patient is having a previous ECG that previous ECG should not be showing any T wave inversion that patient should have developed a new T wave inversion that new T wave inversion appeared on the ccg which was not present on the ECG which was taken at the arrival so it is not present in an old ECG that counts as a T wave inversion and remember an important Point T wave inversion is a normal variant in lead 3 AVR and V1 so you do not look at these three leads whenever you are trying to find out T wave inversion you should not look at lead 3 AVR V1 other than these leads if there is T wave inversion in two or more continuous leads that indicate sub endocardial ischemia now look at this ECG in this ECG look at the T wave inversion in lead one look at the T wave inversion in lead 2 look at the T wave inversion in AVL look at the T wave inversion in lead V4 V5 V6 that is the classical T wave inversion that indicates subbandocardial ischemia and remember lead three AVR and V1 should not be considered for P wave inversion other than these leads now in this ECG these leads are not showing T wave inversion and we are not even considering these leads we are having T wave inversions in lead one two lead V4 V5 V6 so that is that important significant finding in ECG and that also indicates sub endocardial ischemia if you liked my video please click on the Subscribe button and make sure to watch my previous videos on a six step method as well as watch my videos on a rhythm interpretation I have talked about sinus blocks I have talked about it will flutter ratal fibrillation ventricular tachycardia ventricular fibrillation as well as their managements in detail in a separate playlist in summary we talked about what is sub endocardial ischemia how does it appear the different patterns of sub endocardial ischemia negatively deflected most indicative no deflection moderatively indicative positive deflection least indicative Tu inversion also indicates sub-endocardial ischemia if you liked my video please click on the Subscribe button and make sure to check out my other videos on ECG interpretation Made Easy and emergency medicine lectures the link of those videos is given in the description below thank you very much

Channel: MedNerd - Dr. Waqas Fazal

Views: 49,335

Keywords: NSTEMI ecg, nstemi ecg interpretation, nstemi ecg vs stemi, nstemi ecg finding, nstemi ecg ch, nstemi ecg changes, subsendocardial, subendocardial ischemia, subendocardial infarction, subsendocardial ischemia ecg ch, subendocardial ischemia ecg, ischemia ecg changes, ischemia and infarction ecg, myocardial infarction ecg, myocardial infarction ecg changes, MI ecg, mi ecg interpretation, mi ecg changes, mi ecg reading, T wave, t wave inversion in ecg, t wave inversion

Id: PPD5zVFNa_M

Length: 8min 29sec (509 seconds)

Published: Sat Jul 22 2023