Catheter ablation is a minimally invasive procedure used to treat certain heart rhythm disorders, such as atrial fibrillation or ventricular tachycardia. During the procedure, a thin, flexible tube called a catheter is inserted into a blood vessel and guided to the heart. The catheter delivers radiofrequency energy or extreme cold to destroy or isolate the abnormal heart tissue that is causing the arrhythmia. Catheter ablation is considered a safe and effective treatment option for many patients with heart rhythm disorders, particularly those who have not responded well to medication.