MEDICAL ANIMATION TRANSCRIPT: Depending on activity level, the heart beats about 60 to 100 times per minute. It may be higher during exercise or lower at rest. A normal heart rate and rhythm ensures the delivery of oxygen-rich blood to all of the body's organs, such as the brain and lungs. A group of cells in the heart, called the cardiac conduction system, uses electrical impulses to control the speed and rhythm of each heartbeat. An abnormal heart rate or rhythm, called an arrhythmia, occurs when there's a problem with the heart's conduction system. Tachycardia is a type of arrhythmia where the heart beats too fast. Fibrillation is a type of arrhythmia where the heart beats irregularly and may be too fast. For certain types of arrhythmias, a catheter ablation procedure may be necessary to stop the heart tissue from causing the arrhythmia. After numbing a small area in the groin with a needle, the doctor will insert a short hollow tube called a catheter sheath into the femoral vein. Next, a long, flexible tube, called a catheter, will be inserted through the sheath. The doctor will guide the catheter to the heart through a blood vessel that goes to the heart, called the inferior vena cava. The location and progress of the catheter will be monitored. When the catheter reaches the heart, the doctor will guide it to the area that is causing the arrhythmia. The doctor will find the problem areas using a 3-D map of the electrical activity of the patient's heart. The tip of the catheter will emit either hot energy or cold energy to ablate the tissue in this area. Ablation makes the treated area stop working. For an atrial arrhythmia, a doctor will ablate the atrial tissue causing it. If the affected tissues are small, well-defined areas, the procedure is called focal ablation. Or, if the affected tissues are larger areas with more complex rhythm disturbances, the doctor may perform a procedure called ablation remodeling. Both types of ablation restore normal electrical impulses and prevent an arrhythmia from happening. If the cause of the arrhythmia is in the ventricle, the doctor can do either focal ablation or ablation remodeling to treat more complex arrhythmias of the ventricle.