$BSGM These ablation procedures treat cardiac arrhythmias, which are broadly defined as a set of conditions in which the electrical activity of the heart is irregular, or faster or slower than normal. This type of heart disease afflicts 14.4 million Americans, or one in 18. Two of the most prevalent and deadly types of arrhythmias today are Atrial Fibrillation (AF) and Ventricular Tachycardia (VT).