[Acute inferior myocardial infarction masking the J wave syndrome. Based on four observations]

Area of Science:

• Cardiology
• Electrophysiology

Background:

• J wave syndrome encompasses early repolarization syndrome, Brugada syndrome, and idiopathic ventricular fibrillation, marked by J waves and ST elevation without structural heart disease.
• Acute coronary syndromes are common causes of ST deviation, but their effect on J wave syndrome ECG manifestations is poorly understood.

Observation:

• This report details four cases of acute inferior ST-elevation myocardial infarction.
• Patients initially presented with J waves (or J point depression) and ST depression in right precordial leads.
• These ECG changes resolved, replaced by prominent J waves (R') and anterior ST elevation, suggesting a coexisting J wave syndrome.

Findings:

• Acute inferior myocardial infarction can obscure J wave syndrome.
• ST depression in right precordial leads during inferior myocardial infarction may mask underlying J wave abnormalities.
• The transient ECG changes observed suggest a dynamic interplay between ischemic injury currents and J wave syndrome pathophysiology.

Implications:

• Early identification of J waves or J point depression during acute myocardial infarction is crucial.
• This may aid in diagnosing underlying J wave syndromes, such as early repolarization syndrome or Brugada syndrome, even when masked.
• Recognizing these ECG patterns can improve risk stratification and management of patients with potentially life-threatening arrhythmias.