Sinus bradycardia

Sinus bradycardia is a heart rhythm characterized by a resting heart rate of fewer than 60 beats per minute, originating from the sinoatrial node. It is clinically significant as it can indicate underlying conditions such as increased vagal tone, myocardial ischaemia, or drug effects, potentially leading to symptoms like dizziness or syncope. A key association is with athletes, who may exhibit sinus bradycardia as a normal physiological adaptation to increased cardiovascular efficiency.