Diagnosis of ST elevation myocardial infarction (STEMI) is based on clinical presentation, high level of cardiac markers detection and ECG picture. According to 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation, there is "...ST-segment elevation in at least two contiguous leads as STEMI".
Quote from H.Akbar et al. Acute STEMI (2021) with corresponding citations:
"Evaluation of patients with acute onset of chest pain should begin with an electrocardiogram (ECG) and troponin level. The American College of Cardiology, American Heart Association, European Society of Cardiology, and the World Heart Federation committee established the following ECG criteria for ST-elevation myocardial infarction (STEMI)[14]:
New ST-segment elevation at the J point in 2 contiguous leads with the cutoff point as greater than 0.1 mV in all leads other than V2 or V3
In leads V2-V3 the cutoff point is greater than 0.2 mV in men older than 40 years old and greater than 0.25 in men younger than 40 years old, or greater than 0.15 mV in women
Patients with a pre-existing left bundle branch block can be further evaluated using Sgarbossa's criteria[15] [16]:
ST-segment elevation of 1 mm or more that is concordant with (in the same direction as) the QRS complex
ST-segment depression of 1 mm or more in lead V1, V2, or V3
ST-segment elevation of 5 mm or more that is discordant with (in the opposite direction) the QRS complex"
Book Acute Myocardial Infarction ST Elevation (STEMI)
MI with ST elevation is known STEMI. ECG is considered as cornerstone for diagnosing the myocardial ischemia or infarction. American heart association guidelines mainly rely on patients symptoms and ECG for diagnosing Myocardial infarction as STEMI and NSTEMI. But We can rely on ECG upto certain extent because it can help to diagnose the patient with MI , even by paramedic staffs, not guide the treatment.and Alone ECG having low sensitivity and specificity as compared with the ECG, clinical symptoms and serum cardiac marker. So we can rely on ECG only upto certain extent
In STEMI patients, If by doing ECG at earliest possible time and recognise the possible DX.You can save many LIFE by cut down the FMC ( First medical contact) to needle time and Door to baloon time Which is ideally < 30 minutes and < 90 minutes respectively
ECG our oldest but best friend in diagnosis of MI in particular STEMI . however we can miss STEMI in 5 %case as ECG may be normal.si dear Ramakrishna we have to rely on ECG fully as once STEMI is diagnosed in ECG we can do thrombolysis at the same time clinical scenario is important so we can repeat ecg If we have high suspicious of STEMI
Of course , ECG is still cornerstone for diagnosing STEMI but should be correlated with brief patient symptomatology and serum cardiac marker to make it more specific and sensitive
ECG is still the first line diagnostic modality for STEMI. Whenever possible do it first along with correlation with clinical findings like Levine sign present ( Ischaemic chest pain) and presence of Cardiac marker (CK-MB , Troponin) indicating Necrosis of cardiac tissue make the diagnosis more Specific
If its relevant to your investigation model: Do consider that upper abdominal and intracranial lesions may produce ST-changes. ECG is a screening approach and the diagnosis of myocardial lesion ( necrosis) requires typical course of elevation of biomarkers.
Universal definition of acute myocardial infarction includes presence of elevated or changing cardiac biomarker as corner stone. If the ECG changes is associated with enzyme changes thd diagnosis of myocardial infarction is most reliable. According to previous definitions by WHO, 2 of the 3 criteria ( ECG changes, enzyme changes and typical anginal pain) was required to make the diagnosis of myocardial infarction. So ECG changes along with typical anginal pain make the diagnosis much reliable. The other causes of the ST elevation in the ECG are : vasospastic angina, pericarditis, hyper repolarization syndrome, LBBB pacing etc.
Exactly true Chowdhury Sir, ECG , Serum cardiac marker and Typical anginal pain makes the diagnosis most reliable . But ECG is still cornerstone for initial diagnosis more of STEMI versus NSTEMI
Ecg along with biomarkers will be the best choice for diagnosis of MI. Ecg is more over first investigation anyone does while suspension of mi so it should be supported by cardiac enzymes.
Typical anginal symptoms usually guides us, most of time but sometime Atypical anginal symptoms misguide or can mask or raise the doubt of diagnosis of STEMI. In such situations ECG play excellent role in diagnosis ing STEMI.
There is elevation of the ST segments in the inferior leads associated with reciprocal ST depression in leads I and aVL. The electrocardiogram (ECG) is compatible with both acute evolving inferior ST elevation myocardial infarctions or aneurysm.
https://www.ncbi.nlm.nih.gov › pmc
ST-segment elevation: Distinguishing ST elevation myocardial infarction ...
Yes Aref Sir , ECG is still cornerstone for making Diagnosis but doing Serial ECG as said by Chowdhury sir , will be more valuable if initial ECG is not Conclusive
Dear Dr Kakarla Ramakrishna , Upto certain extent we can rely on ECG . Other Parameters incorporated with ECG to make the diagnosis more reliable or conclusive.( More specific)
Your question is written as though it requires some editing. Not sure exactly what you are asking.
If you want to know how sensitive and specific the ECG is when diagnosing (or excluding) an acute MI (without any other clinical data), it's well-known that sensitivity is only 35-40% and that specificity is close to 90%. The higher the ST elevation, the more likely it reliably predicts but "tombstones" are not seen very commonly when considering all-comers with a STEMI.
Yes Kriegh Sir , Tombstones are not seen intiallly ,seen as event pass on or it is time sensitive lack of R wave seen an Tombstones or based on R wave theory
Regardless of any theory, my point is just that the higher the ST elevation, (such as with "tombstones") the more ECG appearance is inarguable. Tombstones are just not that common. And they will appear within15-30 seconds of a coronary occlusion involving a large infarct zone.
The reason the sensitivity is so poor in the setting of an MI (or any of the other presentations of ACS) is because the vast majority of acute MI ECG's involve much lesser degrees of ST elevation to the extent they are indistinguishable from any number of non-infarct conditions. Secondly, most MI's don't involve enough tissue mass to produce that unmistakable enormous ST elevation. The concept of sensitivity and specificity derives from a population of patients, not from an individual case.
Yes Sensitivity and specificity is ability of test and it is independent of disease prevalence .but unlike Sensitivity and specificity ,PPV and NPV are depends on diseases prevalence
The ECG findings of an acute anterior myocardial infarction wall include: ST segment elevation in the anterior leads (V3 and V4) at the J point and sometimes in the septal or lateral leads, depending on the extent of the MI. This ST segment elevation is concave downward and frequently overwhelms the T wave. https://www.healio.com/cardiology/learn-the-heart/ecg-review/ecg-topic-reviews-and-criteria/anterior-wall-st-elevation-mi-review
Identifying an acute myocardial infarction on the 12-lead ECG is the most important thing you can learn in ECG interpretation. Time is muscle when treating heart attacks. Missing a ST segment elevation MI on the ECG can lead to bad patient outcomes. https://www.healio.com/cardiology/learn-the-heart/ecg-review/ecg-interpretation-tutorial/stemi-mi-ecg-pattern
Estimation of specific biomarker in plasm can be detected in Isoproterenol induced MI . Biomarker like glucose , taurine , creatine ,threonine level significantly decreased and histamine, linoleic arachidinoic acid significantly increased , detected by Liquid chromatography. Hypolipidemic drug particularly rosuvastatin can have protective effect against Isoproterenol induced MI
Vitamin C is playing a role in isoproterenol induced MI to counteract oxidative stress induced injury of myocardium by isoproterenol because Vitamin C act as stong reducing agent
We can rely on ECG upto certain extent but along with clinical presentation Cardiac maker Chance of pick up MI increased. ECG is good for screening but not diagnostic purpose