Sinus Bradycardia Causes and Treatment

Causes of Sinus Bradycardia

Medications such as beta blockers, non-dihydropyridine calcium channel blockers, digoxin, antiarrhythmic drugs, lithium, methyldopa, risperidone, cisplatin, and interferon can cause sinus bradycardia, according to the American Heart Association 1
Toxins like toluene, organophosphates, tetrodotoxin, and cocaine can induce bradycardia, as reported in Circulation 1
Acute myocardial ischemia or infarction can cause sinus bradycardia, as stated in the American College of Cardiology guidelines 1
Electrolyte abnormalities, such as hyperkalemia, hypokalemia, and hypoglycemia, can contribute to sinus bradycardia, according to the American Heart Association 1
Hypothyroidism is a potential cause of sinus bradycardia, as noted in the American Thyroid Association guidelines 2

Symptoms of sinus bradycardia can range from mild fatigue to frank syncope, with severity generally correlating with heart rate or pause duration, as reported in the Journal of the American College of Cardiology 4
Common symptoms include syncope, dyspnea on exertion due to chronotropic incompetence, lightheadedness, and chronic fatigue, according to the American College of Cardiology 4

The American College of Cardiology recommends evaluating and treating reversible causes of sinus bradycardia before considering permanent pacing 1, 2
Atropine (0.5-1 mg IV) is a reasonable treatment for patients with symptomatic bradycardia associated with hemodynamic compromise, as stated in the Journal of the American College of Cardiology 5
Permanent pacemaker implantation is indicated when symptoms directly correlate with bradycardia and reversible causes have been excluded, according to the American College of Cardiology 2, 6
Physiological pacing (atrial or dual-chamber) is superior to VVI pacing for sick sinus syndrome, as reported in the Journal of the American College of Cardiology 6