Bored Review – Just Another RV Infarction

I’d like to thank our 4th year resident, Dr. Michael Griesinger, for essentially giving me this entire lecture in real time as he diagnosed and treated an inferior STEMI with right ventricular (RV) infarction yesterday. He nailed every aspect of it. Everything I researched today was just confirmation.

So let’s talk about RV infarction.

 

When should I worry right ventricular infarction?

Any inferior MI (ST segment elevation in leads II, III and aVF) should raise the concern for right ventricular involvement. Over 30% of inferior MIs include RV infarction. The inferior wall of the heart is typically supplied by the right coronary artery (RCA), which also supplies much of the right ventricle. The more proximal the occlusion of the RCA, the more likely it will result in RV infarction.

 

How do you diagnose RV infarction?

A few clues on the ECG of inferior wall MIs make RV infarction more likely:

  • ST elevation in lead III > lead II
  • ST elevation in V1

 

However, all patients with inferior MIs should have another ECG performed with right-sided leads. This can be done by laying out V1-V6 across the right side of the chest in the same (“mirrored”) distribution as they would be on the left.

 

The diagnosis of RV infarction is made by ST elevation >1 mm in V4R.

 

Physical exam findings that suggest RV dysfunction are jugular venous distention with clear lungs.

 

 

<—JVD

 

 

 

 

 

 

Why is diagnosing RV infarction important?

Right ventricular involvement in inferior MI portends a worse prognosis. The most serious consequence of RV infarction is hypotension and shock. The RV is preload-dependent and therefore any drugs that reduce preload should be avoided, particularly nitrates.

In patients with RV infarction, hypotension should be treated with IV fluid resuscitation to increase preload, typically 1-2 liters. If the hypotension persists, then inotropic medications should be started, usually dobutamine.

Finally, patients with RV infarction are more likely to develop bradydysrhythmias due to SA or AV node ischemia from proximal RCA occlusions. Pacer pads should be placed early.

 

As a follow up, our patient yesterday went to cath lab for PCI. The diagnosis of RCA occlusion was confirmed. He was ballooned and is currently doing well.

 

 

Success.

 

Disclaimer: This is a board review post that may be based on relatively outdated textbook information.

 

Hollander JE, Diercks DB. Chapter 53. Acute Coronary Syndromes: Acute Myocardial Infarction and Unstable Angina. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e New York, NY: McGraw-Hill; 2011.

EKGs reproduced from: Nickson, Chris. Right Ventricular Infarction. Life in the Fastlane Medical Blog. Accessed July 17, 2017. https://lifeinthefastlane.com/ecg-library/right-ventricular-infarction

Dima, Claudia et al. Right Ventricular Infarction. Medscape. Accessed July 17, 2017. http://emedicine.medscape.com/article/157961-overview

Levin, Thomas and James Goldstein. 2017. Right Ventricular Myocardial Infarction. UpToDate. Accessed July 17, 2017. https://www.uptodate.com/contents/right-ventricular-myocardial-infarction#H105309893

Morris FrancisBrady William JABC of clinical electrocardiography: Acute myocardial infarction—Part I 

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