@drherm The heavy preponderance of EPs and initial, or 'index' ablations involve the simple PVI....pulmonary vein isolation. This is because almost all patients still paroxysmal, with their AF coming and then self-correcting inside of a full week (yikes, a full week in AF?), have their problem signaling emanating from the ostia of the pulmonary veins....their mouths, where they empty oxygenated blood returning from the lungs, on the rear wall of the left atrium. But the conscientious EP will not release a patient from the cath lab until he has done one, or both of the following: challenged the heart and done a parting cardioversion. The challenge can be done with adenosine, isoproterenol, and even caffeine. The idea is to stimulate the myocytes and electrical system enough that an undetected re-entrant ignites and causes the heart to lurch into arrhythmia. If this happens, the EP knows to keep looking, to keep mapping the endothelial lining of the left atrium, septum, and coronary sinus for that elusive focus. The electro-cardioversion prior to release is like a 're-start' of your computer. Some of us leave our computers on for many days with them in 'sleep' mode. This is fine, but you must do a 're-start' every five/six days to refresh all the files the computer uses for operations. After all the stress of being punctured, probes, cauterized, and then challenged over 120 minutes or so, cardioverting restores the heart's normal state. At least, that's the idea.