EKG Rounds

EKG Rounds

Elizabeth Haney

19 October 2006

Case

32 y.o. Caucasian male presents w/ 4 hours sharp RSCP

Radiation to Lt shoulder and arm Worse with deep inspiration, no exertional change

PMHx: healthy, URTI Sx x 5/7 Meds: occasional tylenol NKDA

Case (cont’d)

Vitals: HR 120 reg, RR 24, BP 124/82 bilat,

T 37.1, O2 sat 99%

O/E: sitting up in bed, moderate distress, otherwise exam normal

EKG

Pericarditis

Overview of the pericardium and pericarditis

4 EKG stages

Differentiating between pericarditis and early repolarization

Pericardium

Back to basics: Pericardium: fibroelastic sac,

composed of parietal and visceral layers with narrow potential space between

Normally contains 15-60ml plasma ultrafiltrate.

Drainage via thoracic duct and right lymphatic duct into Rt pleural space

Pericarditis

Inflammation of

pericardium

Etiology: Most cases idiopathic, with specific etiology in only 22%

Pericarditis

Classical features: RSCP (varies w/ respiration, sharp, worse w/ lying down, relieved w/ sitting up, may radiate to trapezius), EKG abnormalities, +/- pericardial friction rub (~25% of cases)

EKG Findings Changes reflect superficial inflammation of the

epicardium

~90% will show STE, most commonly in leads I,II,V5-6 (70% of patients)

PR depression in all leads except aVR (elevation) may be 1st sign, reflecting repolarization abnormality of atria

Changes follow typical 4 stage evolution over weeks to months

Demangone,D., ECG Manifestations: Noncoronary Heart Disease., Emerg Med Clin N Am 24 (2006) 113-115

4 Stages of EKG changes

Stage I:  Typically occurs during the first hours – days. Diffuse concave-upward ST segment elevation with concordance of T waves; ST-segment depression in aVR or V1; PR segment depression

Stage II: Normalization of ST and PR segments; T wave flattening. Days – weeks.

Stage III: Symmetric T wave inversion. ~ 3 weeks -2 months

Stage IV: Gradual resolution of T-wave inversion (may remain inverted). May last 3 months

What causes STE in the Emerg? LVH with Strain (25%) Undefined STE (17%) Acute MI (15%) LBBB (15%) Benign Early repolarization (12%) RBBB (5%) Non-specific BBB (5%) LV aneurysm (3%) Pericarditis (1%)

Retrospective review of 202 patients with chest pain and STE >1mm in limb leads, >2mm precordial leads, 2 or more contiguous leads

Brady WJ et al. Cause of ST Segment Abnormality in ED Chest Pain Patients. Am J Emerg Med 2001; 19: 25-28.

Benign Early Repolarization

Normal EKG variant

May be related to enhanced vagal tone

Prevalent in patients with high (T5 or higher) spinal cord injuries where sympathetic flow interrupted

Males > Females

Predominantly age <50

Incidence 1-2%

Rosen’s, Mehta, et al. Early Repolarization. Clin.Cardiol. 1999; 22, 59-65

Early Repolarization

Characterized by:1. Diffuse ST segment elevation on EKG2. Upward concavity of the initial portion of the ST segment3. Notching of the terminal portion of the QRS complex at the J point

(jcn of QRS with ST)4. Symmetrical, concordant T waves of large amplitude5. Relative temporal stability over time

Maximal STE typically in precordial leads V2-V5

Rosen’s

How can we distinguish between Early Repolarization and Pericarditis?

ST/T Ratio Tool

ER vs. PericarditisPericarditis Early

ST Concave up Concave up

ST:T in V6 >0.25 <0.25

ST elevation location limb and precordial leads

precordial leads

PR depression present absent

Temporal change in EKG

present absent

Summary

4 stages of Pericaritis EKG changes

Ddx of STE

Early Repolarization

Use of the ST/T wave ratio to help differentiate pericarditis from early repolarization

References

www.uptodate.com Marx: Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6th ed.,

2006; Ch. 81: 1280-88 Demangone,D., ECG Manifestations: Noncoronary Heart Disease., Emerg

Med Clin N Am 24 (2006) 113-115 Brady WJ et al. Cause of ST Segment Abnormality in ED Chest Pain

Patients. Am J Emerg Med 2001; 19: 25-28. Mehta, et al. Early Repolarization. Clin.Cardiol. 1999; 22, 59-65

Pericarditis vs. AMIPericarditis MI

ST Concave Up Convex

Reciprocal Changes Absent Present

ST elevation Limb and precordial Specific coronary territory

Q waves Absent/no evolution Evolution

T wave inversion After ST segments return to baseline

Before/as ST segments elevate

PR depression Present Absent unless atrial infarct