Prolonged ST interval

An electrocardiographic abnormality characterized by prolongation of the ST segment (normally 80–120 ms), resulting in an increased QT interval (≥470 ms) without prolongation of the T-wave duration. It reflects delayed ventricular repolarization and may increase the risk of ventricular arrhythmias.

Causes

• Electrolyte and metabolic causes

  • Hypocalcemia

  • Hypokalemia

• Genetic causes

  • Long QT syndrome

  • Congenital ion channel abnormalities affecting ventricular repolarization

• QT-prolonging medications

  • Antiarrhythmics

  • Some antibiotics

  • Antidepressants

  • Antipsychotics

• Other causes

  • Bradycardia

  • Myocardial ischemia or infarction

  • Myocarditis

  • Hypothermia