Sinus bradycardia does not necessarily refer to the presence of an obvious pathology; in fact, it may occur in normal, healthy individuals including well-trained athletes, some elderly people or during sleep.  It may also be due to an exaggerated response to normal physiological processes (e.g. vomiting, coughing, defecation) or from pathologies involving the SA node such as sick sinus syndrome, myocardial infarction.  The most common medications causing sinus bradycardia are beta blockers, digitalis and calcium channel blockers.  However, life-threatening conditions including chemical poisoning (organophosphate, sarin), sepsis, electrolyte imbalance should be promptly recognized and treated.
Sinus bradycardia causes
Sinus tachycardia causes
Bradycardia causes
Sinoatrial arrest causes
Inappropriate sinus tachycardia causes
Junctional tachycardia causes
Atrial flutter causes
Supraventricular tachycardia causes