Downsloping TP segment seen as an early ECG manifestation in ~80% of patients with pericarditis, best visualised in leads II and the lateral precordial leads

Spodick sign V4 downsloping TP segment
Spodick sign: Downsloping TP segment

ECG changes associated with Stage I pericarditis, first described by David H. Spodick in 1974. The sign remained relatively unevaluated until a recent retrospective analysis in 2020. Witting et al, considered an ECG to demonstrate Spodick’s sign when at least two leads had TP downsloping of at least 1 mm.

Clinical significance
  • Potential useful distinguishing ECG feature between acute pericarditis and ACS
  • Witting found that Spodick’s sign occurred in 29% of patients with pericarditis and 5% of patients with STEMI (OR 5.9)
  • PR depression alone can be a masquerader as it is seen in 12% of patients with STEMI
  • A separate prospective study by Porela et al found that PR depression had a high sensitivity (88%) for myopericarditis but a low specificity

In 1973 and 1974, Spodick described the classic four-stage evolution of electrocardiographic changes with pericarditis, including ST elevations and PR depressions.

Note: Less than 50% of patients progress through all four classical stages and evolution of changes may not follow this typical pattern

Spodick specifically described downsloping of the T-P segment, alter termed the Spodick sign

…the electrocardiographic registration of atrial injury in acute pericarditis is analogous to that of the stage 1 ventricular subepicardial injury in that each follows the orientation of its respective normal recovery (T) wave.

Since most atrial tissue lies posteriorly, to the right, and relatively cephalad of the ventricles, the orientation of a vector of generalized atrial injury (AP-R) would be expected to be to the right and superior (as shown by the frontal plane AP) and also posterior. The predominant P-R segment depressions across the precordium document the posterior component.

Because of these P-R segment deviations, it is of practical importance in acute pericarditis to consider the T-P segment to be the electrocardiographic base line to avoid mistaking P-R segment depression for S-T segment elevation.

Spodick 1974
Spodick sign in stage 1 pericarditis
ECG of a 42-year-old man diagnosed with acute idiopathic/viral pericarditis. ECG represents Stage-1 pericarditis with diffuse PR-segment depression and ST segment elevation (except leads V1 and aVR where PR elevation is noted). Rhythm strip from lead II represents PR depression, ST elevation with slightly downward sloping TP segment (Spodick sign as depicted by blue arrow). Spodick sign is often best recognized in lead II as in this ECG illustration. [Chaubey VK, Chhabra L. 2014]

Differentiating STEMI from pericarditis

The most discriminating features remain as ST depression, ST elevation in lead III >II, and absence of PR depression. It is thus still recommended to look for features of STEMI first on the ECG with ST elevation:

  • Search for ST depression (aside from leads aVR and V1)
  • Look for ST elevation in III > II
  • Search for horizontal or convex upward ST elevation

Following this, additional features such as Spodick’s sign can be reviewed to further differentiate the diagnosis of pericarditis.

Adapted from “Evaluation of Spodick’s sign”: Witting et al

Examples
ECG Pericarditis 2

Acute pericarditis:

  • Sinus tachycardia
  • Widespread concave STE and PR depression (I, II, III, aVF, V4-6).
  • Reciprocal ST depression and PR elevation in V1 and aVR
  • Spodick’s sign best visualised in lead II

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MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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