Bradycardia

When the resting heart rate of an adult is less than 60 beats/ minute, the condition is termed as bradycardia. Clinical symptoms generally appear when the heart rate goes below 50 beats/ minute.
In case of atheletes the heart rate may be even below 50 beats/ minute.

Causes-

1. Normal esp in athletes, young healthy individuals
2. Medications - Calcium channel blockers, beta blockers, digitalis, clonidine, amiodarone, anti-arrhythmic drugs.
3. Sick sinus syndrome
4. Vaso vagal response
5. Hypothermia
6. Hypothyroidism
7. Arterioventricular blocks.
8. Myocardial ischaemia involving right coronary artery.
9. increased intracranial pressure (Cushing's reflex)
10. Cardiac infiltrative diseases - amyloidosis, sarcoidosis, hemochromatosis.