Sick Sinus Syndrome

Excerpt

Sick sinus syndrome, also known as sinus node dysfunction (SND), is a disorder of the sinoatrial (SA) node caused by impaired pacemaker function and impulse transmission producing a constellation of abnormal rhythms. These include atrial bradyarrhythmias, atrial tachyarrhythmias and, sometimes, bradycardia alternating with tachycardia often referred to as “tachy-brady syndrome.” These arrhythmias may result in palpitations and tissue under-perfusion leading to fatigue, lightheadedness, pre-syncope, and syncope.