Sinus bradycardia

Causes:

• congenital
• hypothyroidism
• hypothermia
• post myocardial infarct
• raised intra-cranial pressure
• drugs eg beta-blockers, digitalis, hypotensives
• rapid rise in blood pressure
• sinoatrial disease ('sick sinus syndrome')
• transient increase in vagal tone eg after vomiting
• physical training
• convalescence from fever
• hypersensitive carotid sinus syndrome
• neurocardiogenic syndrome
• jaundice

Click here for an example ECG and further information concerning sinus bradycardia

Reference:

1. Kusumoto FM et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2019 Aug 20;74(7):e51-156.