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 1 st 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)

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:

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 EKG 2. Upward concavity of the initial portion of the ST segment 3. 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 amplitude 5. 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. Pericarditis PericarditisEarly STConcave up ST:T in V6>0.25<0.25 ST elevation locationlimb and precordial leads precordial leads PR depressionpresentabsent Temporal change in EKG presentabsent

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 Marx: Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6 th ed., 2006; Ch. 81: Demangone,D., ECG Manifestations: Noncoronary Heart Disease., Emerg Med Clin N Am 24 (2006) Brady WJ et al. Cause of ST Segment Abnormality in ED Chest Pain Patients. Am J Emerg Med 2001; 19: Mehta, et al. Early Repolarization. Clin.Cardiol. 1999; 22, 59-65

Pericarditis vs. AMI PericarditisMI STConcave UpConvex Reciprocal ChangesAbsentPresent ST elevationLimb and precordialSpecific coronary territory Q wavesAbsent/no evolutionEvolution T wave inversionAfter ST segments return to baseline Before/as ST segments elevate PR depressionPresentAbsent unless atrial infarct