ABSTRACT
The focal theory of atrial fibrillation [AF] has tempted the electrophysiologists to try radically curing AF via radiofrequency [RF] ablation. Interventional ablation depended on localizing and precisely recording pulmonary vein potentials [PVPs] from the origins of the 4 pulmonary veins [PVs] and less commonly from the ostia of the superior vena cava [SVC], and coronary sinus [CS]. The present study is intended to assess the prevalence and feasibility of recording PVPs in patients [pts] with paroxysmal and persistent AF. The study included 27 pts, [14M, 13F] of variable age groups [27-62 yrs], mean age 39.3 +/- 10 and highlysymptomatic paroxysmal and/or persistent AF. refractory to more than two antianhythmic drugs. all had normal thyroid functions. All pts were subjected to left atrial mapping after a trans-septal puncture and introduction of 2 catheters, one via an 8F femoral sheeth [the Lasso catheter] a special circumferential pulmonary vein catheter for recording, and the other was the ablation catheter. Pulmonary venography preceded the PV-mapping to localize the site and to delineate the size of PV and hence the diameter of the lasso catheter that will be used. A coronary sinus hexapolar catheter was placed distally in the coronary sinus. PV potentials were mapped in both sinus rhythm [for Rt. PVs] and with distal coronary sinus or left atrial appendicular [LAA] pacing [for left PVs]. An arrhythmogenic PV was defined on the basis of documented ectopy [single or multiple] with or without conduction to the LA. PV potentials can be described as sharp electrical activity superimposed on atrial activity, that can be separated by LAA pacing in the Left sided veins. or recorded without pacing from Rt sided veins. One hundred and four out of 108 PVs were mapped. Pulmonary venous potentials could be recorded in 25 out of 27 left superior PVs [92.6%], 21 out of 26 left inferior PV [80.8%], 20 out of 25-" right superior PVs [80%] and in 19 out of 26 right inferior PVs [73%]. Pts were arbitrarily divided according to age into 2 age groups; 14 below 40 and 13 above the age 40y. Compared to the younger age oup, those above 40 yrs. exhibited significant lower prevalence of PVP [3.6 +/- 0.6 Vs 2.6 +/- 1.3 respectively]. proximal CS and the former was superceded by pacing from LAA. PVPs cou1dnt be recorded in 2 out of 27 LSPVs, 5 out of 26 LIPVs, 5 out of 25 RSPVs. 7 out of 26 RIPVs, Four PVs were not mapped due to technical problems. Three cases were complicated with cardiac tamponade the first due to puncture of the LA appendage with the transieptal needle, the case due to extensive ablation and the 3 due to over anticoagulation. Two ps [7.4%] developed mild pericardial effusion that was asymptomatic and disappeared during follow-up and one developed TIA. No mortality was recorded. Pulmonary vein potential recording is an essential prerequiste for successful RE ablation of focal AF using Lasso technique. Our data point to the feasibility anti safety of recording in non rheumatic cases and stress the importance of the learning curve. Left superior, Left inferior, Rt superior, Rt inferior pulmonary veins in that order of frequency are arrhytbmogenic foci generating PV potentials. Left sided and superior PVs are more frequently a source of PVPs representing triggers that initiate AF than right sided and inferior PVs. The prevalence of PVPs recording progressively declines with aging possibly pointing to the increasing role of micro reentry in the genesis of AF and the diminishing of PV triggers. Identification of PVPs is highly important and could be easily detected without pacing in case of Rt sided PVs and with CS or LAA pacing for left sided PVs. Pacing from distal CS was noted to promote better separation of PVPs from the atrial activity than pacing from proximal CS and the former was superceded by pacing from LAA