The sinoatrial or sinus node (SAN) is the heart’s natural pacemaker. Located in the superior right atrium, it automatically produces cyclical electrical activity to initiate each heartbeat in normal sinus rhythm. SAN dysfunction (SND) in humans, also known as ‘sick sinus syndrome’, can manifest as pathological bradycardia and asystolic pauses. As a result, SND can lead to symptoms of reduced cerebral perfusion such as dizziness and syncope. However, early SND may be latent and individuals may remain asymptomatic.