What does the Spodick sign on an ECG indicate and what are the recommended next steps for evaluation and management?

Spodick Sign: ECG Indicator of Acute Pericarditis

Spodick sign is a downsloping TP segment on ECG that indicates acute pericarditis, and when present, you should proceed with echocardiography to assess for pericardial effusion and evaluate for hemodynamic compromise, while ruling out STEMI through clinical context and additional ECG features.

What Spodick Sign Indicates

Spodick sign is a specific ECG finding characterized by downsloping of the baseline TP segment (the interval between the T wave and P wave). This finding is statistically associated with acute pericarditis, appearing in approximately 29% of pericarditis cases 1. However, it's critical to recognize that this sign is not pathognomonic—it occurs in about 5% of STEMI patients 1, making it a supportive but not definitive diagnostic feature.

The sign reflects the inflammatory process affecting the pericardium and is frequently overlooked by clinicians despite its diagnostic utility 2.

Critical Differential: Distinguishing Pericarditis from STEMI

Since both conditions present with chest pain and ST elevation, you must use additional ECG criteria to differentiate them:

Features favoring STEMI over pericarditis:

• ST depression in leads other than V1 and aVR (odds ratio 31) 1
• Greater ST elevation in lead III than lead II (odds ratio 21) 1
• Absence of PR depression (odds ratio 12) 1
• Abrupt ST segment take-off (RT checkmark sign) 1
• Upward or horizontal ST convexity 1

Features favoring pericarditis:

• Diffuse ST elevation (rather than territorial distribution)
• PR depression 1
• Presence of Spodick sign 2, 1

Recommended Evaluation Steps

When Spodick sign is identified:

1. Assess clinical stability: Check vital signs and hemodynamic status
2. Complete ECG analysis: Look for diffuse ST elevation, PR depression, and absence of reciprocal changes
3. Troponin measurement: Recognize that troponin can be elevated in myopericarditis 2
4. Echocardiography: Essential to detect pericardial effusion, assess for tamponade physiology, and evaluate ventricular function 3
5. Consider coronary angiography if diagnostic uncertainty remains, particularly when STEMI cannot be excluded based on clinical and ECG features 2

Management Approach

According to ESC guidelines, the diagnostic workup for suspected pericarditis should include 3:

• ECG monitoring: Can show low QRS voltage, generalized T-wave changes, atrial abnormalities, or atrial fibrillation
• Chest X-ray: May reveal pericardial calcifications or pleural effusions
• Echocardiography: Identifies pericardial thickening, effusion, and indirect signs of constriction including chamber enlargement and normal systolic function

Important Caveats

Do not dismiss the possibility of STEMI based solely on Spodick sign presence—5% of STEMI patients will have this finding 1. The clinical context, troponin kinetics, and comprehensive ECG interpretation must guide your decision-making.

Be aware that artifact can mimic ECG changes; ensure proper electrode placement and consider repeating the ECG if findings seem inconsistent with the clinical picture 4.

If hemodynamic compromise is present (hypotension, elevated jugular venous pressure, pulsus paradoxus), immediately assess for cardiac tamponade with urgent echocardiography, as this requires emergent pericardiocentesis 3.