Clinical Significance of RV Infarction
Right ventricular infarction complicates up to 40% of inferior STEMIs. Isolated RV infarction is extremely uncommon.
- Patients with RV infarction are very preload sensitive (due to poor RV contractility) and can develop severe hypotension in response to nitrates or other preload-reducing agents.
- Hypotension in right ventricular infarction is treated with fluid loading, and nitrates are contraindicated.
The ECG changes of RV infarction are subtle and easily missed!
How to spot right ventricular infarction
The first step to spotting RV infarction is to suspect it… in all patients with inferior STEMI!
In patients presenting with inferior STEMI, right ventricular infarction is suggested by the presence of:
- ST elevation in V1 – the only standard ECG lead that looks directly at the right ventricle.
- ST elevation in lead III > lead II – because lead III is more “rightward facing” than lead II and hence more sensitive to the injury current produced by the right ventricle.
Other useful tips for spotting right ventricular MI:
- ST elevation in V1 > V2.
- ST elevation in V1 + ST depression in V2 (= highly specific for RV MI).
- Isoelectric ST segment in V1 with marked ST depression in V2.
Right ventricular infarction is confirmed by the presence of ST elevation in the right-sided leads (V3R-V6R).
Right-sided leads
There are several approaches to recording a right-sided ECG:
- A complete set of right-sided leads is obtained by placing leads V1-6 in a mirror-image position on the right side of the chest (see diagram, below).
- It may be simpler to leave V1 and V2 in their usual positions and just transfer leads V3-6 to the right side of the chest (i.e. V3R to V6R).
- The most useful lead is V4R, which is obtained by placing the V4 electrode in the 5th right intercostal space in the midclavicular line.
- ST elevation in V4R has a sensitivity of 88%, specificity of 78% and diagnostic accuracy of 83% in the diagnosis of RV MI.
NB. ST elevation in the right-sided leads is a transient phenomenon, lasting less than 10 hours in 50% of patients with RV infarction.
Example ECG
Example 1a
Inferior STEMI. Right ventricular infarction is suggested by:
- ST elevation in V1
- ST elevation in lead III > lead II
Example 1b
Repeat ECG of the same patient with V4R electrode position:
- There is ST elevation in V4R consistent with RV infarction
Example 2
Another example of right ventricular MI:
- There is an inferior STEMI with ST elevation in lead III > lead II.
- There is subtle ST elevation in V1 with ST depression in V2.
- There is ST elevation in V4R.
Example 3
This ECG shows a full set of right-sided leads (V3R-V6R), with V1 and V2 in their original positions. RV infarction is diagnosed based on the following findings:
- There is an inferior STEMI with ST elevation in lead III > lead II.
- V1 is isoelectric while V2 is significantly depressed.
- There is ST elevation throughout the right-sided leads V3R-V6R.
Example 4a
Try this one yourself…
Reveal Interpretation
- Inferior STEMI with STE in III > II
- Reciprocal ST depression in aVL and I
- Isoelectric / slightly elevated ST segment in V1 with ST depression in V2-3
- These findings are consistent with inferior STEMI due to RCA occlusion, plus likely associated RV infarction.
Example 4b
Same patient, 9 minutes later…
Reveal Interpretation
- Rapid evolution of inferior STEMI with dynamic increase in height of ST segments – this patient needs urgent PCI!
- V4R shows loss of R-wave height, significant ST elevation (> 0.5mm; ST segment > R wave) and hyperacute T wave (very large T wave given amplitude of QRS complex) – this confirms the diagnosis of RV MI.
- Development of Wenckebach 2nd degree AV block indicates AV node ischaemia or a Bezold-Jarisch reflex (increased vagal tone often seen with inferior MI).
Related Topics
References
- Morris F, Brady WJ. ABC of clinical electrocardiography: Acute myocardial infarction-Part I. BMJ. 2002; 324: 831-4. [full text]
- Edhouse J, Brady WJ, Morris F. ABC of clinical electrocardiography: Acute myocardial infarction-Part II. BMJ. 2002; 324: 963-6. [full text]
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest
Advanced Reading
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric
- Wagner GS. Marriott’s Practical Electrocardiography 12e
- Chan TC. ECG in Emergency Medicine and Acute Care
- Rawshani A. Clinical ECG Interpretation
- Mattu A. ECG’s for the Emergency Physician
- Hampton JR. The ECG In Practice, 6e
ECG LIBRARY
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John Cronin says
March 9, 2019 at 03:31really excellent explanation, thanks