is he having the big one?

Is He Having The Big One?

Sirous Partovi, M.D.

Department of Emergency Medicine

TTUHSC, El Paso

ECG #1- 68 year old with chest pain for 3 days

ECG #2- 66 year old man with 1 hour history of chest pressure

ECG #3- 39 year old AAM with chest pain, PMH HTN

ECG #4 - 62 year old with profuse diaphoresis and vomiting

ECG #5-72 year old male- PMH: CRF,a-fib presents with generalized weakness for

1 hour.

ECG #6- 45 year old female with onset of chest discomfort 2 hours

ago – PMH ?Cancer

ECG #7 – 50 year old man with crushing substernal chest pain for 30 minutes

ECG #8- 72 year old female with history of HTN found unconscious

ECG #9- 67 year old man with PMH of MI in respiratory failure due to

acute CHF

ECG #10- Chest pain radiating to the jaw in a 41 year old woman

Objectives Understand the etiology of chest pain Distinguish between Acute Coronary

events requiring thrombolysis and those that do not.

Recognize the more common conditions that may cause a pseudo-infarction pattern on ECG.

Chest Pain

2% of all ED visits 10-20% are diagnosed with AMI 1.7 million admissions to hospitals

annually $5 Billion spent on admitted patients

which AMI was subsequently ruled out in

Chest Pain- AMI

1.1 million cases of AMI annually 50% present to EDs 2%-8% rate of misdiagnosis 11,000 missed diagnosis of MI per

year 20% of money awarded in

malpractice cases

Differential Diagnosis of Chest Pain

Cardiac Ischemic

Angina Unstable

angina AMI

Non-ischemicPericarditisAortic dissectionValvularMyositis


Non-cardiac Gastroesophageal Causes

GERD Esophageal spasm PUD Boerhaave’s Syndrome Cholecystitis


Non-cardiac Non-gastroesophageal

Pneumothorax Pulmonary embolism Musculoskeletal Somatoform disorders

Chest Pain-Diagnosis

History and Physical ECG Cardiac serum markers

AMI- World Health Organization (WHO)

Definition A combination of two of three

characteristics: Typical symptoms (i.e., ischemic-type

chest discomfort) A rise and fall in serum cardiac markers Typical ECG pattern involving the

development of Q waves

Acute MI - History 70%-80% present with ischemic type

CP Less than 25% of patients admitted to

hospital with ischemic-type CP are diagnosed with AMI

Unusual symptoms for AMI Elderly Women Diabetics

Features of H&P That Increase the Probability of AMI

Panju et al, JAMA. 1998;280:1256-1263

History and Physical LR Chest pain radiating to both arms 7.1 Third heart sound 3.2 Hypotension 3.1 Chest pain radiating to right shoulder 2.9

Likelihood Ratio

Positive LR Odds that a patient with a positive

test result has the target disorder Pos LR= Sensitivity/(1-Specificity)

Negative LR Odds that a patient with a negative

test result has the target disorder Neg LR= (1-Sensitivity)/Specificity

Historical Features That Decrease the Probability of AMI

Panju et al, JAMA. 1998;280:1256-1263

Quality of Chest Pain LR Pleuritic 0.2 Sharp or stabbing 0.3 Positional 0.3 Reproduced by palpation 0.2-0.4

ECG evolution in Q-wave Myocardial Infarction

Tall peaked T-waves ST-segment elevation Appearance of abnormal Q wave Decrease of ST-segment elevation

with the beginning of T-wave inversion Isoelectric ST-segment with

symmetrical T-wave inversion

Tall T- Waves

The earliest sign of AMI Due to subendocardial ischemia Within minutes or hours after the

onset of chest pain Transient Most ECGs fail to show this pattern



with the beginning of T-wave inversion

Isoelectric ST-segment with symmetrical T-wave inversion

ST-Segment Elevation

The most common early ECG sign STE - specificity 91% , sensitivity 46% Mortality increases with the number of

ECG leads showing ST elevation STE decreases in the first 7-12 hours STE resolves within 2 weeks in 90% of

IWMI, but only in 40% of anterior MI

Reciprocal ST-Segment Depression

Seen in up to 82% Marked early, 50% resolve within 24

hours Due to reciprocal electrical alteration Increases specificity of AMI to 99% Seen in 72% of IWMI Indicative of:

Larger AMI Lower ventricular ejection fraction Higher mortality


Tall peaked T-waves ST-segment elevation represents a

stage beyond ischemia -i.e. injury Appearance of abnormal Q-wave Decrease of ST-segment elevation



Abnormal Q-Waves

Most commonly presents while ST-segment still elevated

12-20% of Q-waves do not persist CHF is more common with

persistent Q-waves


Tall peaked T-waves ST-segment elevation represents a

stage beyond ischemia -i.e. injury Appearance of abnormal Q wave Decrease of ST-segment elevation



Criteria for Thrombolysis

ST elevation (greater than 1 mm in two or more contiguous leads), time to therapy 12 hours or less, age less than 75 years.

Bundle branch block (obscuring ST-segment analysis) and history suggesting acute MI.

AMI Diagnosis- ECG

Factors Influencing ECG Interpretation

Clinical observation of the patient Knowledge of clinical data Training and experience of interpreter

AMI Diagnosis- ECG

Gjorup et al, J Intern Med. 1992; 231: 407-412

16 IM residents read 107 ECGs Looking for signs indicative of AMI Disagreement in 70% of the cases

AMI Diagnosis- ECG

Willems et al, NEJM. 1991; 325:1767-1773

8 cardiologists interpreted 1220 ECGS High interobserver agreement - of

0.67 125 ECGs read twice

Different diagnosis for 10%-23% of ECGs

AMI Diagnosis- ECG

Massel et al. Am Heart J. 2000;140:221-6

3 cardiologists - 75 ECGs 2 occasions (within 7 days) First reading: Presence or absence

of thrombolysis eligibility criteria Second reading: criterion 1 plus the

subjective opinion that the changes represented acute transmural injury

AMI Diagnosis- ECG

Interobserver variability in thrombolytic therapy eligibility

Is there 1 mm ST elevation?

Does this represent an AMI?

Agreement kappa

Agreement kappa

Rater 1 vs 2 93.3 86.2 94.7 88.2

Rater 2 vs 3 88.0 75.8 94.7 88.0

Rater 1 vs 3 86.7 72.9 94.7 88.2

Overall

78.2

88.5

Errors in AMI

ECG of a patient who is otherwise eligible may be incorrectly interpreted as being nondiagnostic

ST-segment elevation may be erroneously interpreted as suggesting an AMI, resulting in the inappropriate overuse of thrombolysis

Errors in AMI – Missed Diagnosis



Errors in AMI - Missed Diagnosis

McCarthy et al, Ann Emerg Med.1993;22:5795-82 Rate of missed AMI among 6 NE hospitals 1050 patients with AMI

1.9% misdiagnosed 25% of the patients with missed AMI had

STE of at least 1 mm Death or severe complications in 25% of

pts

Errors in AMI - Missed Diagnosis

Pope et al, NEJM 2000;342:1163-70

10,689 patients, 10 hospitals (ACI-TIPI trial)

17% had acute cardiac ischemia (ACI) 8% AMI 9% UA

6% stable angina 21% other cardiac diagnosis 55% noncardiac diagnosis


Pope et al

Of 894 AMI patients, 19 (2.1%) was missed

8 (47%) had one of the following ECG readings: LVH, LBBB, BER, pericarditis

7 (41%) minor ST segment abnormality with <1mm of ST segment deviation

14 of 19 had NQWMI


Brady et al, AEM, April 2001 11 ECGs with STE 45 yo male with HTN, DM and chest

pain 458 EPs


Brady et al, AEM, April 2001 Overall rate of correct

Errors in AMI



Errors in AMI - Over Diagnosis

Lee et al, Ann Int Med 1989;110:957-62.

No AMI in 25% of patients with acute chest pain and ST-segment elevation

For every 8 patients appropriately treated with a thrombolytic agent 1 or 2 will be treated unnecessarily

Errors in AMI-Over Diagnosis

Sharkey et al, Am J Cardiol 1994;73:550-3

93 patients with chest pain receiving thrombolytic therapy, AMI did not occur in 10 (11%) LVH- 30% BER- 30% IVCD- 30%

Impact of Errors

Bleeding consequences Life-threatening bleed- 0.4% Moderate bleed- 5%

Not treating an eligible thrombolysis candidate

Financial consequences Missed AMI is the leading cause of

malpractice loss in the ED setting

Causes of ST Segment Elevation

Cardiac Acute myocardial infarction Variant (Prinzmetal's) angina Acute pericarditis Left ventricular aneurysm Left ventricular hypertrophy Bundle branch blocks Benign Early repolarization


Metabolic Hyperkalemia Hypothermia (Osborne or "J" waves) Hyperventilation


Miscellaneous Acute abdominal disorders

(pancreatitis, cholecystitis, peritonitis) Central nervous system hemorrhage Medications (type I anti-arrhythmic

agents, isoproterenol) Body habitus Idiopathic

Localization of Acute MI

LOCATION ECG LEADS INVOLVED

PROBABLE ARTERY INVOLVED

Anteroseptal V1, V2 Proximal LAD septal perforator

Anterior V2, V4 LAD or its branches

Anterolateral V4- V6, I, aVL

Mid LAD or circumflex

Extensive Anterior

V1-V6 Proximal LAD

Inferior II,II,aVF RCA, circumflex, distal LAD

High lateral I, aVL Circumflex or branch of LAD

Posterior V1, V2 Posterior descending

Right ventricle V1, rV3- rV4 RCA

ECG #1- 32 year old with chest pain at a party

Anterolateral MI

Anterolateral MI - II

Anterolateral MI - III

65 year old with acute chest pain

Anterior MI

Acute Anterior MI

Acute Anteroseptal MI

Acute Anterior MI

Acute Anteroseptal MI

53 year old with severe light headedness, nausea, diaphoresis, and upper abdominal pain. Bloods pressure

85/palp.

Acute Inferoposterior MI

R

R

R

R

R

Acute Lateral MI

ECG #4 - 62 year old with profuse diaphoresis and vomiting

ECG #7 – Acute Posterior MI - Old inferior MI

Inferior MI

(MR# 866159) -77 year old male with chest pain and palpitation

Anterior MI

LVH with ST-T Wave Changes

Left Ventricular Hypertrophy

Definition ECG diagnosis: based on the increase of

the QRS voltage Possible LVH - only voltage evidence of LVH Definite LVH - voltage evidence of LVH

associated with ST-T wave changes (strain) Strain pattern – characterized by

downsloping ST depression with asymmetric, biphasic, or inverted T wave (occurs in 70% of cases)

LVH With Strain and CAD

50% prevalence of demonstrated CAD in asymptomatic hypertensive patients with LVH and strain vs. 4% general population

60% of patients with LVH and strain had reversible perfusion defects on Thallium scintigraphy

LVH

ECG is 93-96% specific and 12-29% sensitive in diagnosing LVH

Echocardiography- 86% specificity and 100% sensitivity for diagnosis of LVH

LVH

Otto LA et al, Ann Emerg Med 1994;23:17-24

Prehospital study of adult chest pain patients with STE

Majority did not have AMI LVH and LBBB were most common

LVH

Brady WJ, J Emerg Med

STE resulted from AMI in only 15% LVH was the most frequent cause

of this STE (30%)

LVH

Larsen et al, J Gen Intern Med 1994;9:666-673

10% of patients diagnosed in the ED with acute ischemic heart disease have LVH

Only 26% of these patients were found to have unstable angina or AMI

Physicians incorrectly interpreted the ECG more than 70% of the time

LVH by Voltage Only

Cornell Criteria- RaVL+SV3 >24 mm in males >20 mm in female

LVH by Voltage Only

Other commonly used voltage-based criteria Precordial leads (one or more)

RV5 or V6 + SV1 >35 mm if age> 30 years >40 mm if age 20-30 years >60 mm if age 16-19 years

Maximum R wave + S wave in precordial leads >45 mm

RV5 > 26 mm RV6> 20mm

LVH by Voltage Only

Other commonly used voltage criteria Limb leads (one or more)

RaVL >12 mm RI + SII >26 mm RI >14 mm SaVR >15 mm RaVF >21 mm

LVH by Voltage

RV5+SV1=43mm

RV5= 37mm

LVH by Both Voltage and ST-T Segment Abnormalities

Voltage criteria for LVH ST-T segment abnormalities

ST segment and T wave deviation opposite in direction to the major deflection of QRS

ST segment depression in leads I, aVL, III, aVF +/- V4-V6

Subtle ST elevation (1-2 mm) in leads V1-V3

Inverted T waves in leads I, aVL, V4-V6 Prominent or inverted U waves





Subtle ST elevation (1-2 mm) in leads V1-V3 Inverted T waves in leads I, aVL, V4-V6 Prominent or inverted U waves





Subtle ST elevation (1-2 mm) in leads V1-V3

Inverted T waves in leads I, aVL, V4-V6 Prominent or inverted U waves





Subtle ST elevation (1-2 mm) in leads V1-V3 Inverted T waves in leads I, aVL, V4-V6Prominent or inverted U waves

Romhilt and Estes LVH Point Score System

QRS Voltage – 3 points for the presence of any 1 criteria R or S in limb leads 20 mm S in V1 or V2 30 mm R in V5 or V6 30 mm

Typical ST-T repolarization abnormality Without digitalis – 3 points With digitalis – 1 point

LAD - 30° or more – 2 points QRS duration 0.09 sec – 1 point ID V5-6 0.05 sec – 1 point LAE – 3 points

LVH With ST-T Abnormalities

R in I = 15mm

S in aVR > 14mm

RV5>26mmRV5+SV1=65mm

R in aVL + S in V3 >24mm

LVH With ST-T Abnormalities

34 year old AAM with chest pain-No PMH

Benign Early Repolarization

First described in 1936 by Shipley A normal variant- 1% general

population Common in athletes BER-in adult ED chest pain patients

~13% BER is seen on ECGs 23-48% of adult

ED chest pain patients who have used cocaine

Benign Early Repolarization

Mean age - 39 (16-80) Most commonly less than 50 years

of age- older than 70 years(3.5%) Seen in men much more often

than women

ECG Criteria For BER Elevated take-off of ST segment at the J point Upward concavity of the initial portion of the

ST segment Notching or slurring on downstroke of R wave Symmetric, concordant T waves of large

amplitude Widespread or diffuse distribution of ST

segment elevation on the ECG - most commonly in leads V2-V5, sometimes in inferior leads

No reciprocal ST segment change relative temporal stability

J point elevation- less than 3.5 mm ST segment appears as if it has been

lifted evenly upward STE is less than 2 mm in 80-90% Only 2% of cases STE is greater than 5

mm.

J point

Upward concavity




segment elevation on the ECG-most commonly in leads V2-V5, sometimes in inferior leads


Tall symmetric T wave

Benign Early Repolarization (BER)

Acute Pericarditis

Acute Pericarditis

Stage 1- Concave up ST segment elevation

Stage 2- ST segment normal, flattening of the T waves

Stage 3- T wave inversion without Q wave formation

Stage 4- Normalization of ECG

Acute Pericarditis- Other ECG Clues

Sinus tachycardia PR depression early Low voltage QRS Electrical alternans if pericardial

effusion

BER or Pericarditis ST segment elevation in the two syndromes

is similar PR segment in pericarditis is often depressed ST segment elevation in acute pericarditis

tends to be widespread across the ECG T waves in pericarditis frequently is of normal

amplitude and morphology, whereas the T wave in BER is frequently altered

The ratio of the ST segment elevation to the height of the T wave (ST/T) is also a helpful guide; a ratio greater than 0.25 in lead V6 strongly suggests pericarditis

Pericardial Effusion

Electrical Alternans

BER or AMI

ST-T wave complex waveform Reciprocal changes Evolutionary changes

LBBB- ECG Criteria

Prolonged QRS duration( 0.12 sec) Delayed onset of intrinsicoid deflection in

leads I,V5, V6 Broad monophasic R waves in leads I, V5,

V6 Secondary ST & T wave changes opposite in

the direction to the major QRS deflection rS or QS complex in right precordial leads LAD may be present

LBBB- ECG Criteria



V6 Secondary ST-T wave changes opposite in


LBBB- ECG Criteria



V6 Secondary ST & T wave changes opposite in


QS

QS

LBBB With MI

Fulfills criteria for LBBB Three criteria (Sgarbossa criteria)

with independent value for diagnosing AMI: ST elevation 1 mm concordant to the

major deflection of the QRS ST depression 1 mm in V1, V2, or V3 ST elevation 5 mm discordant with the

major deflection of the QRS

LBBB with Inferolateral MI

ECG #2- 66 year old man with history of LBBB and 1 hour history

of chest pressure

LBBB and AMI

LBBB and AMI

Sgarbossa criteria 96% specific Pos LR = 22 Neg LR = 0.8

RBBB- ECG Criteria

QRS duration 0.12 sec Delayed onset of ID Increased amplitude of the R’ in V1-

V2 Wide, slurred S wave in leads I,V5,V6 Secondary ST-T abnormality

RBBB

Most patients with RBBB have CAD Many have no evidence of

underlying heart disease In patients with AMI, RBBB is

present in 3-7% of cases In uncomplicated RBBB, there

usually is little ST-segment displacement

AMI in The Presence of RBBB

RBBB does not interfere with the recognition of infarcts.

Even in presence of RBBB and either LAHB or LPHB, infarcts can be evaluated normally-EXCEPT True posterior MI

RBBB, Inferoposterior MI

RBBB+LAHB+Anterolateral MI

RBBB+LPHB+Anteroseptal

30 year old diabetic found unresponsive

Hyperkalemia

ECG #5-72 year old male, PMH: CRF and a-fib presents with generalized

weakness for 1 hour.

72 year old female found unresponsive

ECG and ICH

Most commonly SAH Altered autonomic tone as a

mechanism Abnormalities include

ST-segment elevation or depression Large, wide, upright , or inverted T waves Long QT interval Prominent U wave

70 year old asymptomatic man with PMH of MI

75 year old man found unresponsive on a park bench, on New Years Eve,

in Fargo…

Many causes of STE Features that increase likelihood of

AMI New STE New Q waves Any STE New LBBB

is he having the big one?

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