aka ECG Exigency 015
A 68 year-old woman collapsed at home, as witnessed by her son who commenced CPR. She was in ventricular fibrillation when the paramedics arrived, and reverted to sinus rhythm following defibrillation at the scene. She was intubated prehospital and transferred to your emergency department. She remains intubated and unconscious, and she has a blood pressure of 75/50 mmHg.
This is her ECG:
Q1. Describe and interpret the ECG.
- SR 90/min (borderline for 1st degree heart block), normal axis.
- ST elevation in the inferior leads (II, III, aVF)
- ST elevation in V1, V2 and V3
- Reciprocal ST depression in lateral leads (I, aVL and V6)
- Inferior STEMI with right ventricular involvement, due to acute proximal occlusion of the right coronary artery.
- Haemodynamically unstable RV infarction is associated with high mortality.
Key features suggesting RV infarction are
- ST elevation in V1
- ST elevation in lead III > lead II
Note that about one quarter to one third of inferior STEMIs are associated with RV infarction, and nearly 90% of RV infarctions occur with coexistant inferior MI.
Q2. What is the relevance of leads V1 and V2 to the diagnosis in this case?
ST segment elevation in V1 should always make you suspect the presence of RV infarction.
The typical findings of RV infarction in V1 and V2 are:
- ST elevation in V1 exceeding the magnitude of ST elevation in V2
- ST segment in V1 is isoelectric and the ST segment in V2 is markedly depressed
These findings are not present in the ECG of our patient. Although ST elevation is usually restricted to lead V1 in RV infarction, it can occasionally extend across the precordial leads as shown in this ECG.
Q3. What can be immediately done at the bedside to confirm the diagnosis?
Repeat the ECG with right-sided precordial leads.
ST elevation in V4R confirms RV infarction, as shown in this repeat ECG:
Q4. Describe your approach to management.
The approach to management includes:
- Immediate activation of the cath lab.
- Employ a team-based approach to resuscitation in an appropriately equipped and staffed resuscitation area.
- Confirm ETT placement, adequacy of oxygenation (target SaO2 94-98%) and ventilation.
- Obtain large bore IV access and commence full non-invasive monitoring (SpO2, ETCO2, BP, ECG and temperature)
- Treat cardiogenic shock due to RV infarction:
— 250 mL crystalloid boluses followed by reassessment (targeting adequate end organ perfusion, usually with MAP >65 mmHg)
— maintain preload by avoiding nitrates and excessive intrathoracic pressures (e.g. avoid high PEEP)
— maintain atrio-ventricular synchrony
— transfer to the cath lab for cardiac catheterisation ASAP
- Commence therapeutic hypothermia (but do not delay transfer to the cath lab)
- Commence supportive care of the intubated patient (e.g. FAST HUGS IN BED Please!)
This patient’s presentation is consistent with a critical right coronary artery occlusion requiring emergent reperfusion therapy. Ideally, transfer to the cath lab should occur so rapidly that there is insufficient time to do much else!
If percutaneous coronary intervention (PCI) is not available, then thrombolysis — though not as effective, particularly in the presence of cardiogenic shock — should be performed. Following thrombolysis, transfer to a facility with a cath lab is still a priority (for rescue therapy and/or further investigation).
In addition to judicious fluid boluses (to improve preload and RV function), ongoing hypotension may be treated with catecholamine infusions (e.g. dobutamine, noradrenaline), levosimendin (a calcium sensitiser), and devices such as intra-aortic balloon pumps (LV dysfunction may result from the inferior STEMI component) until definitive treatment can be performed.
References and Links
- ECG Library — RV infarction
Journal articles and textbooks
- Berent R, Auer J, von Duvillard S, Sinzinger H, Steinbrenner D, Schmid P. Acute myocardial infarction with ST segment elevation in inferior and anterior leads: right ventricular infarction. BMJ Case Rep. 2010;2010. pii: bcr03.2009.1700. Epub 2010 Jan 13. PubMed PMID: 22242057; PubMed Central PMCID: PMC3028157.
- Chan T, Brady W, Harrigan R, Ornato J, Rosen P. ECG in Emergency Medicine and Acute Care. Mosby, 2004.
- Walker LA, Buttrick PM. The right ventricle: biologic insights and response to disease. Curr Cardiol Rev. 2009 Jan;5(1):22-8. PubMed PMID: 20066144; PubMed Central PMCID: PMC2803284.