ECG/EKG versus smartwatch for myocarditis/pericarditis and myocardial infarction

In his latest video, Dr. Seheult of MedCram discusses myocarditis/pericarditis versus myocardial infarction (also known as a heart attack) and how to differentiate between them and whether a smart watch can differentiate between them.

Smart Watch ECG/EKG features

Some of the newest smart watches have an ECG/EKG feature that allows you to look at the heart rhythm. The ECG/EKG is basically a photograph of how electricity is moving throughout the heart at different angles. A traditional ECG/EKG has 12 leads. In a smart watch, only one lead is used and is limited to Lead 1. As the smart watch will only provide one lead viewpoint, it will not be possible to distinguish between myocarditis/pericarditis and myocardial infarction with a smart watch alone.

Myocarditis/Pericarditis vs Myocardial Infarction

Myocarditis/pericarditis looks different on an EKG compared to a myocardial infarction. The space between the visceral pericardium (lining that touches the heart directly) and the parietal pericardium (lining that does not directly touch the heart) is called the pericardial cavity. This can fill up with fluids, one of which is blood. Pericardial inflammation is generally seen all throughout the heart so on an ECG/EKG, all leads would reflect the inflammation as evidenced by ST segment elevation. This is indicative of pericarditis when there is diffuse ST elevation throughout all of the leads on an ECG/EKG. This needs to be distinguished from a myocardial infarction where the ST segment elevation would be seen in only a portion of the leads as usually only a portion of the heart, ie one or two blood vessels, is typically involved in a “heart attack.” This would not lead to global changes on the ECG/EKG  unlike in pericarditis. 

Risks of misdiagnosing pericarditis and myocardial infarction

Getting the diagnosis is extremely critical as consequences to a misdiagnosis can be serious.  One of the potential treatments for myocardial infarction involves the use of a TPA like drug otherwise known as a “clot buster.” This is used to prevent new clots from forming as well as break up the clots already there.  This is important because if this was used in someone with pericarditis, giving a “clot buster” drug could lead to more bleeding especially in the pericardial cavity.  This could lead to something known as cardiac tamponade. This is a situation where there is so much fluid around the heart that it ends up squeezing the heart and possibly preventing the heart from working and leading to the death of the patient. On echocardiogram (ultrasound of the heart), in the case of pericardial effusion (fluid around the heart), this is easily seen.

What happens to the heart in a myocardial infarction

In myocardial infarctions, a blood vessel that supplies the heart is either partially or completely blocked and prevented from providing enough blood supply to the part of the heart it services. Depending on the location of the blood vessel, the resulting ischemia (cell injury and death) can be reflected on different leads on the ECG/EKG and can be seen as ST-elevations. After a myocardial infarction, the ECG/EKG will reflect prior injury with what are called Q waves. When these are seen, it implies that the heart has had injury to it sometime in the past.

It is important to distinguish between different leads to determine if someone is having pericarditis or a myocardial infarction. MedCram has an ECG/EKG interpretation course that delves into this and provides 10 CME credits. MedCram also has ultrasound online courses available. MedCram recently partnered with AIM to provide its ultrasound courses in the training of Cambodian physicians. 

 

LINKS / REFERENCES:

ECG Watch: How it Works (MedCram) | https://youtu.be/0HxOWCw4hEU

MedCram helps out Cambodia with Alliance for International Medicine update (MedCram) | https://blog.medcram.com/uncategorize…

Working to alleviate suffering (AIM) | https://www.allianceinmedicine.org

Pericardial effusion with tamponade (Wikimedia) | https://commons.wikimedia.org/wiki/Fi…

Evol Of MI (Wikimedia) | https://commons.wikimedia.org/wiki/Fi…

PericarditisMyocarditis (Wikimedia) | https://commons.wikimedia.org/wiki/Fi…

Inferior and RtV MI 12 lead (Wikimedia) | https://commons.wikimedia.org/wiki/Fi…

ECG / EKG Interpretation Explained Clearly (MedCram) | https://www.medcram.com/courses/ekg-e…

Ultrasound Collection (MedCram) | https://www.medcram.com/collections/u…

 

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