Defintion of Arrhythmias A disturbance in electrical activity means the heart won't function as smoothly as it should. Such a disturbance leads to an arrhythmia, a term that means any abnormality in the heart's normal rhythm or beat. Arrhythmias occur in many forms and are one of the most common heart conditions. Many are benign, and a person may live a long, productive life without requiring any treatment. But some arrhythmias pose serious, life-threatening problems that may require medication, surgery or other therapy.
Some arrhythmias cause a noticeable skip, flutter or palpitation.
Others occur without the slightest symptom and may be detectable only by electronic monitoring of the heart, a procedure known as electrocardiography. Arrhythmias can be divided into two broad categories. Suprventricular disturbances involve structures outside the ventricles, including the atria, the heart's two upper chambers. Tachycardia and bradycardia are caused by sinus rhythm disturbances. Sinus rhythm disturbances arise from changes in the electrical activity of the sinoatrial node, the originating point for heartbeats.