An arrhythmia is a disorder of the heartbeat or rhythm, caused by a disruption of the heart’s normal electrical conduction system. The SA (sinoatrial) node is the heart’s natural pacemaker, sending electrical impulses through the hearts special conduction pathways, signaling the heart’s four chambers to beat in a synchronized manner. Nerve impulses and hormones influence the rate of the beats. Disturbances anywhere along this conduction system can produce an arrhythmia. Causes include by heart disease, stress, caffeine, tobacco, alcohol and certain medications. Sometimes, no cause can be found.  

 
The two general types of arrhythmias are tachycardia, when the heart beats too fast, and bradycardia, when the heart beats too slowly. An arrhythmia can also cause the heart to skip a beat or have an extra beat. Most everyone will experience some form of arrhythmia on occasion. These disturbances are usually harmless. Other arrhythmias, however, are dangerous and require treatment. Arrhythmias originating in the ventricles (lower chambers of the heart) are more serious than those that originate in the atria (upper chambers). Ventricular fibrillation and ventricular tachycardia are life-threatening arrhythmias.

General symptoms of arrhythmias include heart palpitations or rapid thumping in the chest, fainting, light-headedness or dizziness, fatigue, chest pain, and shortness of breath. Arrhythmias can be detected by an electrocardiogram or an electrophysiology (EP) study, a type of cardiac catheterization procedure.

Treatment depends on the type of the arrhythmia and includes, medications to control the heart rate, implantable pacemakers or defibrillators, surgery, and radiofrequency catheter ablation. Some arrhythmias respond to lifestyle changes, such as exercise and avoiding caffeine and nicotine, which are stimulants.