• Clinical science

Supraventricular premature beats

Abstract

Supraventricular premature beats are atrial contractions triggered by ectopic foci rather than the sinoatrial node. They arise within the atria (atrial premature beats) or, through retrograde conduction, in the atrioventricular node (junctional premature beats). Premature beats may be found in healthy individuals as well as patients with underlying heart disease. Certain triggers, e.g., alcohol, smoking or electrolyte imbalances, may also contribute to the condition. Premature beats do not significantly impair cardiac output on their own; however, they may lead to more severe forms of arrhythmia such as atrial fibrillation. Unless patients exhibit severe symptoms (e.g., tachycardia), those experiencing premature beats do not require treatment.

Etiology

  • Idiopathic
  • Potential triggers: smoking, alcohol, coffee
  • Cardiovascular disease or electrolyte imbalances (e.g., hypokalemia)

References:[1]

Classification

Atrial premature beats

  • Definition: extrasystole that originates in the atrial myocardium and occurs prior to the expected QRS complex
  • Typical findings on ECG
    • P-wave abnormalities or absent P waves
    • Altered PR interval in the premature beats (compared to the normal beats)
    • QRS complex may be normal, aberrant (widened), or absent
    • No full compensatory pause

Junctional premature beats

  • Definition: premature beat that occurs prior to the expected QRS complex and that originates between the atria and ventricles
  • Typical findings on ECG

References:[1]

Clinical features

  • Usually asymptomatic
  • Palpitations

Diagnostics

  • ECG: identify supraventricular premature beats (SPBs)
  • Echocardiography: to rule out structural heart disease and evaluate cardiac structure and function if SPBs are identified on ECG or Holter monitor
  • Further work-up: if structural abnormalities are present

References:[1]

Treatment

  • Treatment is not required in asymptomatic individuals without underlying structural heart defects.
  • Underlying conditions, e.g., electrolyte imbalances, should be treated.
  • Symptomatic patients
    • Advise patients to reduce potential triggers like caffeine, alcohol, stress and smoking.
    • Beta blockers or catheter ablation in patients with persistent symptoms

References:[1]