The function of the sinoatrial node is complex. In nearly all hearts, this small bit of tissue is responsible for spontaneously generating the impulse which will be distributed to the remainder of the heart, maintaining coordinated electrical and mechanical function. In recent years, it has become clear that S-A node dysfunction is not rare, can cause disabling symptoms, and often presents difficult management problems. The challenges presented by the Sick Sinus Syndromes have increased our desire to know more about normal S-A node function and about function in disease states
