ACEP 2010_Subtle ECG Manifestations of Deadly Cardiac Ds_Thinking Outside the Pine Box

8/7/2019 ACEP 2010_Subtle ECG Manifestations of Deadly Cardiac Ds_Thinking Outside the Pine Box

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(+)Amal Mattu, MD, FACEPAssociate Professor; Program Director,

Emergency Medicine Residency,

University of Maryland School of

Medicine, Baltimore, Maryland

Subtle ECG Manifestations of Deadly

Cardiac Disease: Thinking Outside

the Pine Box

The electrocardiogram is one of the basic tools

used to detect myocardial ischemia. The ED

physician is trained to look for ST-segment

changes and other flagrant manifestations of

myocardial ischemia, but there are other

indicators. All too often, subtle manifestations

of cardiac disease are missed with fatal

consequences. The speaker will review ECG

findings that could literally mean the difference

between life and death but are easily missed

unless you are specifically looking for them.

Identify subtle ECG manifestations with

potentially fatal outcomes if missed.

Provide an approach to the analysis of the ECG

that will assist in detecting myocardial disease.

Practice ECG analysis in a case-based format.

TU-23

9/28/2010

12:30 PM - 1:20 PMMandalay Bay Convention Center

(+)No significant financial relationships to disclose


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Subtle ECG Manifestations

of Deadly Cardiac Disease

Amal Mattu, MD, FACEPProgram Director, Emergency Medicine Residency

Professor, Department of Emergency Medicine

University of Maryland School of Medicine

Baltimore, Maryland

[email protected]


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Subtle ECG Manifestations of Deadly Cardiac Disease

Amal Mattu, MD2

Case 1, ECG #1 (87 yo. man with nausea, diaphoresis, and pallor)

Case 1, ECG #2 (Baseline ECG)


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Amal Mattu, MD3

Case 2 (32 yo. man with chest pain and dyspnea)

Case 3 (38 yo. woman with positional chest pain)


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Amal Mattu, MD5

Stop!

Please do not look at

the answers to the

preceding cases yet!


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Amal Mattu, MD6

I. Early Reciprocal Changes in Lead aVL

The normal ECG shows an isoelectric ST-segment and upright T-wave in aVL An inverted T-wave in aVL is often found with inferior wall myocardial infarction

Represents a reciprocal change Marriott mayprecede the expected changes in inferior leads; may initially bethe only abnormality found on the ECG of a patient with acute inferior MI or

ischemia

Major exceptions downsloping ST-segment and inverted T-wave in aVL is normalfinding in patients with LVH and LBBB

II. Pulmonary Embolism Simulating Acute Coronary Syndrome

Typical ECG findings SIQIII or SIQIIITIII RBBB or incomplete RBBB (often transient) Rightward axis T-wave inversions, especially in right precordial leads (V1-V3) + inferior leads

Marriott and others: combination of T-wave inversions in right precordial andinferior leads is highly specific for acute pulmonary hyptertension, pulmonary

embolism

May also (less commonly) cause ST-segment depression or elevation in right precordial leads ST-segment depression in leads I or II ST-segment elevation in lead III

Important point: PE often causes ECG changes that resemble cardiac ischemia Dont just rule out MI when the ECG appears to show cardiac ischemia

III. Pericarditis vs. Acute MI

Classic teaching Diffuse ST-segment elevation

May be localized rather than diffuse But no reciprocal ST-segment depression! (except perhaps in aVR and V1)

ST-segment elevation is concave upwards Beware that AMI may have similar ST-segment morphology ST-segment elevation that is convex upwards or horizontal strongly favors

AMI

Additional pearl regarding ST-elevation STE II > STE III strongly favors acute pericarditis STE III > STE II very strongly favors acute MI

PR-segment depression (downsloping)


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Amal Mattu, MD7

Primarily present in viralpericarditis Often an early, transient finding

PR-segment elevation in aVR May also be present in other diseases (e.g. AMI) Often absent in constrictive pericarditis

Chest pain tends to be positional, pleuritic Beware that 16% of AMIs may present with positional or pleuritic pain!

Factorsstrongly favoring AMI: ST-segment elevation that is convex upwards;reciprocal ST-segment depression (in leads other than aVR and V1); known new Q-

waves Factorsstrongly favoring acute pericarditis: pronounced PR-segment depression

(downsloping) in multiple leads; friction rub

IV. Pericardial Effusion

Large pericardial effusions are classically associated with Electrical alternans (usually involves QRS complex, but may involve the P-wave

and/or T-wave also)

Present in < 30% Tachycardia

May be blunted if the patient is taking cardiac medications Low voltage

Defined as QRS amplitude in leads I + II + III < 15 mm OR QRS amplitude inleads V1 + V2 + V3 < 30 mm

Differential diagnosis also includes obesity, COPD, large pleural effusions,severe hypothyroidism, end-stage cardiomyopathies, infiltrative diseases (e.g.sarcoid, amyloid, scleroderma), massive MI

New low voltage (compared to a recent ECG): think pericardial effusion orpleural effusion

Chest pain/pressure and dyspnea are most common Hypotension + JVD often when tamponade is present

CXR usually demonstrates cardiomegaly (very sensitive but non-specific) Always consider the diagnosis in a patient with cardiopulmonary symptoms that

has tachycardia + low voltage!

V. Summary

Reciprocal changes in lead aVL may be the first sign of inferior wall myocardialischemia

Pulmonary embolism can cause ECG changes that simulate ACS Strongly consider PE when the ECG has inverted T-waves simultaneously in the

anteroseptal + inferior leads Dont just rule out MI when the ECG demonstrates classic ischemic changes


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Amal Mattu, MD8

Pericarditis ECGs are often not classic! Very strongly favoring AMI

Reciprocal changes Convex upwards or horizontal morphology of ST-segments New Q-waves

Very strongly favoring pericarditis Pronounced PR-segment depressions in multiple leads Friction rub

Pericardial effusion should be suspected in any patient with LV + tachycardia Especially if LV is new

Recognition of these subtle abnormalities will make the difference between life anddeath!

Dont rely on your cardiology consultants to make these diagnoses Emergency physicians must be the experts in electrocardiography!

References/Suggestions for Further Reading

Now available:ECGs for the Emergency Physician Volume 1. Authors: Amal Mattu, William Brady.

Blackwell Publishing, 2003. A collection of 200 high-quality ECGs with diagnoses and advanced

teaching points. The first 100 ECGs focus on the intermediate level, and the second 100 ECGs

focus on the advanced level emergency practitioner.

Available through the ACEP bookstore, medical bookstores, Amazon.com, or similar sites.

ECGs for the Emergency Physician Volume 2. Authors: Amal Mattu, William Brady.

Blackwell Publishing, 2008. A collection of 200 additional high-quality ECGs with diagnoses

and advanced teaching points. Serves as a complement to Volume 2 with an added focus on

dysrhythmias, misdiagnoses, and advanced topics.Available through the ACEP bookstore, medical bookstores, Amazon.com, or similar sites.

Electrocardiography in Emergency Medicine. Editors: Amal Mattu, Jeff Tabas, Bob Barish.

ACEP Publishing 2007. A textbook of electrocardiography covering basic and advanced topics,

highly illustrated. Available through the ACEP bookstore: https://secure2.acep.org/BookStore/c-

16-cardiology.aspx

Questions or comments? Please contact me:

Amal Mattu, MD

[email protected]

ACEP 2010_Subtle ECG Manifestations of Deadly Cardiac Ds_Thinking Outside the Pine Box

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