bradykardian

Bradykardian is an adjective used in medical contexts to relate to bradycardia, a slower-than-normal heart rate. The term derives from brady-, meaning slow, and -cardia, from the Greek kardia (heart). In practice, bradykardian describes conditions, symptoms, or treatments associated with reduced heart rate.

Bradycardia refers to a resting heart rate below 60 beats per minute in adults, though interpretation varies. In some individuals, such as trained athletes or during sleep, a lower rate can be normal and asymptomatic. Pathologic bradycardia can result from impaired heart rhythm or conduction and may require evaluation.

Common causes include high vagal tone (as seen in athletes or during sleep), intrinsic sinus node dysfunction, atrioventricular conduction block, aging of the conduction system, hypothyroidism, electrolyte disturbances, and drugs that slow the heart (beta-blockers, non-dihydropyridine calcium channel blockers, digoxin). Acute causes include myocardial infarction and myocarditis. Sleep apnea and certain systemic illnesses can also contribute.

Clinical features range from no symptoms to lightheadedness, dizziness, fatigue, near-syncope, or frank syncope, especially with abrupt drops in heart rate or poor cerebral perfusion. Diagnosis is typically based on electrocardiography showing a heart rate under 60 bpm with appropriate rhythm, and may include Holter monitoring or event recording to characterize bradyarrhythmias.

Treatment focuses on the underlying cause and symptom severity. Acute symptomatic bradycardia may be managed with atropine and temporary pacing; chronic or high-grade conduction disease often requires a permanent pacemaker. Medication adjustments and treatment of reversible conditions are important components of care. Prognosis depends on the cause and the effectiveness of therapy.