Early repolarization syndrome

The role of the syndrome in emergency cardiology

The presence of early repolarization syndrome in a patient creates serious obstacles for detecting ST-segment elevation myocardial infarction (STEMI). This syndrome belongs to a large group of conditions and diseases that distort the typical graphic pattern of acute myocardial ischemia.

In addition to the phenomenon under consideration, the diagnosis of myocardial infarction can be complicated by:

• Conduction and rhythm disorders: left bundle branch block, WPW syndrome (pre-excitation with accessory pathway conduction), and paced rhythm from an artificial pacemaker.
• Structural and genetic pathologies: left ventricular hypertrophy and Brugada syndrome.
• Inflammatory processes: acute pericarditis and myocarditis.
• Systemic disorders: pulmonary embolism (PE), severe metabolic disturbances (e.g., hyperkalemia), and cerebrovascular events (subarachnoid hemorrhage).
• Other factors: abdominal diseases (cholecystitis can cause referred ECG changes), cardiomyopathies, and age-related juvenile norms.

It is also important to rule out post-infarction changes, such as the formation of pathological Q waves or a "frozen" ST segment elevation in chronic left ventricular aneurysm. One should not forget about the possibility of commonplace technical errors during electrode placement.

Significance of ECG in infectious diseases

Detecting early ventricular repolarization syndrome is crucial when managing patients with systemic infections. According to current guidelines, recording an ECG in standard leads is indicated for absolutely all patients hospitalized with community-acquired pneumonia.

Goals of mandatory electrocardiographic screening:

1. Rule out life-threatening cardiac complications.
2. Detect hidden comorbid conditions.
3. Determine a safe regimen for drug therapy (including antibacterial treatment).

Clinically, this approach is fully justified. Against the background of pneumonia, the risk of acute coronary syndromes, decompensation of existing chronic diseases, and fatal arrhythmias increases manifold. The detection of early repolarization or QT interval prolongation on the electrocardiogram dictates the necessity for the specialist to select medications with extreme caution. Timely adjustment of the treatment plan considering these electrocardiographic findings directly improves the patient's prognosis for survival.

Differential diagnosis with acute carditis

Electrocardiographic changes characteristic of isolated repolarization abnormalities must be carefully distinguished from severe organic lesions, primarily acute acquired carditis. Acute myocardial inflammation manifests at the peak of the infectious process or immediately after it, most commonly affecting children in their first three years of life.

Unlike the benign electrocardiographic phenomenon, carditis manifests as a complex of pathological changes on the ECG:

• Pronounced repolarization abnormalities: pathological ST segment displacement, formation of flattened or negative T waves (the picture often mimics infarction).
• QRS voltage drop and persistent signs of overload in one or both ventricles.
• A wide spectrum of arrhythmias: sinus tachyarrhythmias and bradyarrhythmias, extrasystoles, as well as intraventricular and atrioventricular blocks (up to complete block).

In addition to ECG criteria, other methods help differentiate the conditions. Radiography in carditis reveals cardiomegaly and signs of venous congestion, while echocardiography demonstrates chamber dilation, wall hypokinesia (of the interventricular septum and posterior wall), and a critical decrease in ejection fraction.

The clinical presentation in myocardial inflammation is also specific. Patients exhibit signs of left ventricular failure: progressive dyspnea, tachycardia, moist rales. Auscultation reveals muffled heart sounds, gallop rhythm, and in severe cases (with Coxsackie virus infection), convulsive syndrome, pronounced cyanosis, and central nervous system involvement. With isolated early repolarization syndrome, such symptoms are absent.

Class and exam questions

What else to study on this topic

• Clinical presentation and trigger factors of acute acquired carditis in children.
• Echocardiographic features in carditis: from chamber dilation to decreased ejection fraction.
• Severe forms of viral infections: combined myocardial and central nervous system involvement by Coxsackie viruses.
• Physical examination findings in myocardial lesions: changes in pulse, heart borders, and auscultatory findings.
• Algorithm for selecting safe antibacterial therapy in the presence of ECG abnormalities.

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.