| Part ?.Pulmonary vein conduction recovery in patients without long-term clinical recurrence after ablation of paroxysmal atrial fibrillation:mechanistic implicationsBackground:Atrial fibrillation(AF)is one of the most common clinical arrhythmia.The exact mechanism of AF is yet to be explored.Catheter ablation has been used as a relatively safe and effective treatment for paroxysmal atrial fibrillation(PAF).Pulmonary vein(PV)isolation had become the most recognized acute procedural endpoint for PAF ablation.However,the recurrence rate after ablation is still high and the reason for recurrence is also unspecific.We have found that despite isolated pulmonary vein-left atrium(PV-LA)conduction,some patients still had AF recurrence,while others had PV-LA conduction recovery,yet they remain in sinus rhythm.Objective:This study aimed to examine the incidence of conduction recovery of PV in patients without clinical recurrence of atrial fibrillation after paroxysmal AF radiofrequency catheter ablation(RFCA),in order to explore the possible role of pulmonary vein potentials in the ling-term recurrence of AF.Methods:The study continuously enrolled 189 PAF patients scheduled to have RFCA in our center from March 2011 to December 2012.After 3 years of follow-up,114 patients were arrhythmic-free.22 of them consented to have electrophysiology study(as non-recurrence group,Group A).22 patients with clinical recurrence after initial RFCA were analyzed for comparison(as recurrent group,Group B).PV reconnections were assessed by circular mapping catheter and PV-LA intervals were obtained as well.Results:In Group A,recovery of PV-LA conduction was observed in 19/22(86.4%)patients while in Group B,21/22(95.5%)patients had PV-LA conduction(P>0.05).Among patients without recurrence,3/22(13.6%)patients had reconnection in all 4 veins,5/22(22.7%)in 3 veins,7/22(31.8%)in 2 veins and 4/22(18.2%)in 1 vein.No anatomic propensity was seen as reconnection was evenly distributed throughout all veins for both groups(Group A:LSPV=9,LIPV=11,RSPV=9,RIPV=10;Group B:LSPV=14,LIPV=12,RSPV=13,RIPV=14,P>0.05 respectively).When compared to patients with recurrence,no significant differences were seen in proportion of patients with reconnection(P>0.05)or in PV-LA intervals(58.6 ± 23.5 ms vs.63.8 ± 31.3 ms,P>0.05).Conclusion:A high incidence of PV reconnection was similarly observed in patients with and without recurrence of AF after 3 years post-RFCA,suggesting that elimination of the triggers and substrates within or along the circumferential ablation lines,not the maintenance of PV isolation,may underlie the long-term success for PAF ablation.Part ?.Atrium substrate in patients without long-term clinical recurrence after ablation of paroxysmal atrial fibrillation:mechanistic implicationsBackground:Long-term successful rate of circumferential pulmonary vein isolation(CPVI)had high recurrence rate after paroxysmal atrial fibrillation(PAF)radiofrequency catheter ablation(RFCA).Some patients had AF recurrence despite isolated pulmonary vein-left atrium(PV-LA)conduction,while others had PV-LA conduction recovery,yet they remain in sinus rhythm.Atrial fibrillation(AF)can cause atrial electrical reconstruction.Low voltage area floating in the atrium can be used as the substrate of slow conduction and activation reentry.These changes of atrial substrate may be the reason for long-term recurrence after RFC A of AF.Objective:This study aimed to compare both left and right atrium substrate in patients with or without clinical recurrence after ablation of paroxysmal atrial fibrillation(PAF),in order to explore the possible role of atrium substrate in the long-term recurrence of AF.Methods:The study continuously enrolled 189 PAF patients scheduled to have RFCA in our center from March 2011 to December 2012.After 3 years of follow-up,114 patients were arrhythmic-free.22 of them consented to have electrophysiology study(as non-recurrence group,Group A).22 patients with clinical recurrence after initial RFCA were analyzed for comparison(as recurrent group,Group B).Electrical-anatomical maps were composed for both groups with 3D mapping system.Mean voltage,low voltage index,conduction velocity and activation time for both atriums were measured and calculated.Results:Atrial mean voltage was 2.13 ± 0.66 mV in Group A and 1.78 ± 0.41 mV in Group B.There is statistical difference in mean voltage of roof,anterior,posterior wall and whole left atrium(P<0.05,respectively).In Group B,low voltage index in roof(1.37 ± 1.01 vs.0.86 ± 0.74,P<0.05),posterior wall(1.18 ±0.54 vs.0.99 ± 0.72,P<0.05)and whole left atrium(1.10 ± 0.50 vs.0.95 ± 0.56,P<0.05)were significantly higher than those in Group A.Both groups had more low voltage areas at roof,anterior and posterior wall,though there were no statistical differences(P>0.05,respectively).Compared to Group A,Group B had slower conduction velocity in roof(1.19 ± 0.26 m/s vs.1.47 ± 0.22,P<0.05),anterior(1.37 ± 0.29 m/s vs.1.51 ± 0.32 m/s,P<0.05),posterior wall(1.25 ± 0.28 m/s vs.1.51 ± 0.21 m/s,P<0.05)and whole left atrium(1.38± 0.27 m/s vs.1.51 ± 0.25 m/s,P<0.05).Patients in Group A also had longer left atrium activation time(106 ± 6 ms vs.91 ± 12 ms)and bi-atrium activation time(144 ± 21 ms vs.137 ± 15 ms)than patients in Group B.There were no statistical differences in mean voltage,low voltage index and conduction velocity in the right atrium between the two groups.Conclusion:Patients with recurrence after PAF RFCA had a trend of more low voltage areas in left atrium than those without.They had lower left atrium voltage,increased low voltage index,slower conduction velocity and longer activation time.There results indicated that besides PV potentials,left atrium substrate might be another underlying reason for long-term AF recurrence after ablation. |
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