Severe pulmonary embolism and evolution of tracings

Tracing
N° 71
Library
Pathology
Patient
67-year-old man followed for renal neoplasia, hospitalized for sudden onset dyspnea with arterial hypotension (SAP of 80 mmHg); the cardiac ultrasound showed a right ventricular dilatation with pulmonary arterial hypertension; the angioscanner confirmed the diagnosis of bilateral massive pulmonary embolism with right ventricular dilatation; this electrocardiogram was performed at entry;
Severe pulmonary embolism and evolution of tracings
Patient
Tracing recorded 2 hours after the initiation of fibrinolysis; slowing of the sinus rate (117 bpm); decrease in the size of the S wave in lead I; T-wave inversion in V3-V4;
Severe pulmonary embolism and evolution of tracings
Severe pulmonary embolism and evolution of tracings
Severe pulmonary embolism and evolution of tracings
Severe pulmonary embolism and evolution of tracings
Comments

The tracings of this patient allow to detail the electrical abnormalities observed during a pulmonary embolism and their evolution over time. In a pulmonary embolism, one can observe:

  • a sinus tachycardia which is common but not obligatory (absent, for example, in patients receiving beta-blocking treatment or in the presence of a small embolus with no hemodynamic strain); the heart rate usually slows down rapidly within a few hours or days; the incidence of supraventricular rhythm disorders (atrial fibrillation preferentially) is approximately 10%;
  • unlike the chronic cor pulmonale, changes in the morphology of the P-wave and the pulmonary P-wave pattern (increase in P-wave amplitude in  lead II, rotation of the P-wave to the right of the frontal axis) are rare in pulmonary embolism;
  • a discrete prolongation of the PR interval is exceptionally observed;
  • changes in the pattern of  the QRS-complexes are relatively frequent, early and transient (they disappear within a few hours to a few days); their detection sometimes requires comparison with previous or subsequent electrocardiograms; in addition to the S1Q3 pattern, one can observe:
  1. an incomplete right bundle branch block with a rSr' or rsR' pattern, possible notching of the upward branch of the S wave and modest widening of the width of the QRS; this modification is precocious and fleeting; the observation of a complete right bundle branch block reflects the presence of a massive pulmonary embolism;
  2. an often limited rotation of the axis in the clockwise direction (from the normal axis to the vertical axis);
  3. displacement toward the left of the QRS transition zone in precordial leads by the recoiling of the left ventricle posteriorly and to the left;
  • repolarization disorders with inversion of the T-wave in leads III, V1, V2, V3 sometimes with an "ischemic" appearance (peaked and symmetrical T-waves, more or less deep); these modifications are sometimes more discreet, asymmetrical and limited to V1; the inversion of the wave T in right precordial leads is the most common electrical sign; it appears slightly delayed compared to changes in the QRS but persists longer (up to several weeks); the T-wave is often unequivocally negative in lead III (S1Q3D3 pattern) whereas it is rather weakly positive or biphasic in lead II; in left precordial leads, repolarization remains mostly normal even if negative T-waves can also be observed; the ST-segment is mostly isoelectric, although changes in the T-wave can sometimes be associated with an ST-segment depression and exceptionally with an elevation.
Epigraph
Inversion of T-waves in right precordial leads and/or in lead III is the most common of the electrical abnormalities (after sinus tachycardia) observed during pulmonary embolism; the occurrence of peaked and symmetrical T-waves is often later than the changes in the QRS-complex, although persisting longer.