Variables affecting PVI success

BARCELONA, SPAIN. It is known that the success or failure of a circumferential pulmonary vein ablation (Pappone method) depends on the amount of existing left atrial scarring observed during mapping, the area ablated in the left atrium, whether or not vagal denervation is performed, and the absence of AF inducibility after the procedure. There is also some evidence that the success rate in the case of non-paroxysmal (persistent and permanent) AF is less than that observed for paroxysmal AF.

Spanish researchers now add to our knowledge regarding pre-procedure factors that affect the final outcome of an anatomically-guided (CARTO) circumferential PVI (CPVA). Their study involved 148 patients, of which the majority (60.8%) had paroxysmal afib, while the remaining had either persistent (23.6%) or permanent (15.6%). The average age was 52 years and 82% were male. Eighty percent experienced lone atrial fibrillation (no underlying structural heart disease) and 33.8% had hypertension.

The patients all underwent a standard CPVA procedure using the CARTO mapping system and an 8-mm irrigated Navistar catheter. The procedure involved lesions encircling both left- and right-sided pulmonary veins as well as linear lesions along the posterior wall of the left atrium and along the mitral isthmus. The patients were followed for an average of 13 months at which time 73.6% were free of afib recurrences. A second procedure was needed in 22 patients (14.8%) because of recurrent afib or the development of left atrial flutter (9.5%), and a third procedure was needed in 4 patients (overall 18% repeat rate). Two patients suffered a TIA during the procedure, 6 developed post-procedural pericarditis, and 3 experienced cardiac tamponade, thus resulting in an overall major complication rate of 7.4%.

The researchers noted that the success rate of the procedure was negatively affected by advanced age, hypertension, permanent afib, elevated left atrial antero-posterior diameter (LAD), and elevated left ventricular end-systolic diameter. However, in multivariable analysis only hypertension (2.8 times risk) and elevated LAD (1.1 times risk) proved to be independent predictors of failure. They conclude that patients with a LAD at or below 45 mm and no hypertension could expect a favourable outcome in at least 85% of cases, while among those with hypertension and an enlarged left atrium (LAD >45 mm), a success rate of only about 50% could be expected.

Berruezo, A, et al. Pre-procedural predictors of atrial fibrillation recurrence after circumferential pulmonary vein ablation. European Heart Journal, Vol. 28, 2007, pp. 836-41

Editorís comment: The finding that hypertension is associated with an almost three times greater likelihood of failure is indeed a sobering one. It is known that hypertension causes left atrial enlargement and fibrosis, but it is not clear whether controlling hypertension (through medications or supplements) will result in a better outcome.