Five ECG Patterns You Must Know

Written by Salim Rezaie REBEL EM Medical Category: Cardiovascular

Background: The electrocardiogram (ECG) is one of the most useful diagnostic studies for identification of acute coronary syndrome (ACS) and acute myocardial infarction (AMI). The classic teaching is ST-segment elevation myocardial infarction (STEMI) is defined as symptoms consistent with acute coronary syndrome (ACS) + new ST-segment elevation at the J point in at least 2 anatomically contiguous leads of at least 2mm (0.2mV) in men or at least 1.5mm in women in leads V2 – V3 and/or at least 1mm (0.1mV) in other contiguous leads or the limb leads, in the absence of a left bundle branch block, left ventricular hypertrophy, or other non-acute MI ST-segment elevation presentations. Unfortunately, the ECG may be non-diagnostic in nearly half of all patients who initially present with AMI. There are also STEMI equivalent patterns that are caused by occlusion of the coronary arteries that place a significant portion of the left ventricle at jeopardy and result in poor outcomes. This review article focused on 5 under recognized high-risk ECG patterns in the ACS patient that result in poor outcomes including malignant dysrhythmias, higher rates of cardiogenic shock, and death.

First Diagonal Branch of the Left Anterior Descending Artery Occlusion

The 1 st diagonal branch (D1) of the LAD supplies blood to the anterolateral wall of the left ventricle

diagonal branch (D1) of the LAD supplies blood to the anterolateral wall of the left ventricle Look for: STE in aVL and V2 Upright T-waves in aVL and V2 ST-Depression and inverted T waves in Inferior Leads (III and aVF)

STE in aVL and V2 + lack of STE in other precordial leads = 89% PPV for MI of the anterior wall caused by a D1 lesion

Image From: Macias M et al. Am J Emerg Med 2015

De Winter’s T Waves

Concerning for proximal LAD occlusion (Present in 2% of patients)

Look for: Upsloping ST-Depression at J Point in leads V1 – V4 without STE Tall, Symmetric T-Wave in leads V1 – V4 STE in lead aVR +/- aVL



Images From: LITFL Blog

Left Main Coronary Artery Stenosis

Look for: STE in lead aVR AND/OR Widespread ST-Depression

In one study STD in leads I, II, and V4 – V6 + STE in aVR present in 90% of patients with greater than 70% stenosis of the LMCA

Left Main Coronary Artery Occlusion will have the same findings as above but patients will be in cardiogenic shock if not coding

Image From: LITFL Blog

Wellens’ Syndrome

Concerning for proximal critical high grad LAD occlusion

Consider Wellens’ if: Active (or recent) angina chest pain Minimal or no cardiac biomarker elevation Absence of pathologic precordial Q waves Minimal or lack of STE (<1mm) No loss of precordial R-wave progression Characteristic T-wave abnormalities

Two Types of Wellens’ Syndrome: Type A (25% of cases) consists of biphasic t waves Type B (75% of cases) consists of deep symmetric t waves

Provocative Stress Testing could prove to have disastrous consequences resulting in AMI and fatal dysrhythmias

AMI can occur within a mean of 6 – 8.5d after admission, but a mean of 21.4d after symptoms

T-wave changes may be transient or resolve with medical management

Look for: Deeply inverted T-waves in leads V1 – V4 OR Biphasic T-waves in leads V1 – V4



Wellens’ Type A (Image From: LITFL Blog)

Wellens’ Type B (Image From LITFL Blog)

Wellens Type A (Image From LITFL Blog)

Wellens Type B (Image From LITFL Blog)

Posterior Wall AMI

Concerning for occlusion of either distal left circumflex artery or PDA of right coronary artery

If you see STD in leads V1 – V3, the next thing to do is get a posterior ECG with leads V7 – V9 to help differentiate posterior AMI vs Anterior Ischemia

Look for: Horizontal (flat) ST-Depression in leads V1 – V3 Prominent R-wave in leads V1 – V2 Upright T-wave in leads V1 – V3



Posterior STEMI (Image From LITFL Blog)

Posterior STEMI with Posterior Leads (Image From LITFL Blog)

Placement of Posterior Leads

Clinical Bottom Line: It is important to recognize the above 5 patterns as these are high risk ACS patients because a significant portion of the left ventricle is at jeopardy. Only 4 of the above diagnoses require activation of the cath lab immediately and the 5th requires consultation of interventional cardiology.

Cath Lab Activation:

1st Diagonal Branch of the Left Anterior Descending Artery Occlusion

de Winter’s T Waves

Left Main Coronary Artery Occlusion

Posterior STEMI

Interventional Cardiology Consultation:

Wellens’ Syndrome

References:

Macias M et al. The Electrocardiogram in the ACS Patient: High-Risk Electrocardiographic Presentations Lacking Anatomically Oriented ST-Segment Elevation. Am J Emerg Med 2015. [epub ahead of print]. PMID: 26742458

For More Thoughts on This Topic Checkout:

Taming the SRU: STEMIs in Disguise

Post Peer Reviewed By: Anand Swaminathan (Twitter: @EMSwami)