Differential Diagnosis for Sinus Rhythm with Minor Inferior Repolarization Disturbance

Single Most Likely Diagnosis

• Benign Early Repolarization: This condition is characterized by an elevation of the QRS-ST junction (J-point) often accompanied by a slight ST elevation in the inferior leads, which can be mistaken for ischemia or repolarization disturbances. It's a common finding in healthy individuals and does not typically indicate cardiac disease.

Other Likely Diagnoses

• Hypertension with Left Ventricular Hypertrophy (LVH): Chronic hypertension can lead to LVH, which may cause minor repolarization abnormalities due to the increased thickness of the left ventricular wall. This condition can lead to LV overload and may present with repolarization disturbances on an ECG.
• Coronary Artery Disease (CAD) with Minor Ischemia: Minor inferior repolarization disturbances can be an early sign of ischemia, possibly due to CAD. Even if the changes are minor, they warrant further investigation, especially in patients with risk factors for CAD.
• Electrolyte Imbalance: Abnormal levels of potassium, calcium, or magnesium can affect the repolarization phase of the cardiac cycle, leading to various ECG abnormalities, including minor repolarization disturbances.

Do Not Miss Diagnoses

• Acute Coronary Syndrome (ACS): Although the ECG changes are described as minor, any sign of ischemia or infarction, especially in the inferior leads, should prompt consideration of ACS, including myocardial infarction. Missing this diagnosis could be catastrophic.
• Cardiac Arrhythmias with Underlying Structural Heart Disease: Certain arrhythmias, when associated with structural heart disease, can lead to significant morbidity and mortality if not recognized and treated appropriately.

Rare Diagnoses

• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): This rare condition affects the right ventricle, leading to fibrofatty replacement of the myocardium. It can present with various ECG abnormalities, including repolarization disturbances, although it more commonly affects the right ventricle.
• Myocarditis: Inflammation of the myocardium can lead to a wide range of ECG abnormalities, including repolarization disturbances. While less common, myocarditis should be considered, especially in the appropriate clinical context (e.g., recent viral illness).
• Pericarditis: Acute pericarditis can cause widespread ST elevation and PR depression on an ECG. While the presentation is usually more dramatic than minor repolarization disturbances, atypical cases or early stages of the disease might only show subtle changes.