Pulmonary Vein Morphology Before and After Segmental Isolation in Patients with Atrial Fibrillation

Marehiko Ueda; Hiroshi Tada; Kenji Kurosaki; Kazuhiro Itoi; Keiko Koyama; Shigeto Naito; Sachiko Ito; Issei Komuro; Shigeru Oshima; Koichi Taniguchi

Disclosures

Pacing Clin Electrophysiol. 2005;28(9):944-953. 

In This Article

Results

The supero-inferior diameter of the PV ostium was greater than the antero-posterior ostial diameter in each of the PVs (P < 0.0001 for each; Table I ). The supero-inferior ostial diameter did not differ among the four PVs, but the antero-posterior ostial diameter of the LIPV was smaller than the other three PVs (P < 0.05 for each). The supero-inferior and antero-posterior diameters of the ostium in the AF patients were greater than those in the control subjects ( Table I ). However, the trunk length of each PV in the AF patients (12.9 ± 7.6 mm) did not differ from the control subjects (11.9 ± 7.4 mm, P = 0.4). The transverse and antero-posterior LA diameters were greater in the AF patients than in the control subjects ( Table I ).

A luminal reduction in the PVs was observed in patients with AF before ablation as well as in the control subjects. In patients with AF, the average luminal reduction of all 112 PVs that were assessed was 6 ± 10% (range, 0–34), and the distance from the ostium to the narrowest point in the PV was 6.7 ± 3.9 mm in the supero-inferior direction and 7.1 ± 4.6 mm in the antero-posterior direction. A luminal reduction was frequently observed and its severity was the greatest in the LIPV among the four PVs ( Table II ). PV narrowing was found in nine (8%) PVs (eight LIPVs and one LSPV; Table II , Fig. 2A and B). Four of the PV narrowings (44%) were found only in the antero-posterior direction, but no PV narrowings were found only in the supero-inferior direction.

In the control subjects, the average luminal reduction was 5.8 ± 13% (range, 0–66%), and PV narrowing was found in six LIPVs (10%). A control subject with mild pectus excavatum had a 66% luminal reduction (Fig. 2C). There were no differences in the incidence or severity of segmental PV narrowing between the AF patients and the control subjects. Inside the LIPVs, six of the eight narrowings (75%) in the AF patients and four of the six narrowings (67%) in the control subjects were dominant on the posterior side adjacent to the descending aorta (Fig. 2B).

RF energy was delivered at the 92 PVs (30 RSPVs, 11 RIPVs, 26 LSPVs, and 25 LIPVs) and complete electrical isolation was achieved in 88 (96%) PVs. In each of the PVs, RF energy was delivered more often at the superior and inferior segments than at the anterior and posterior segments ( Table III , Fig. 4C). No complications occurred during the ablation procedures.

After ablation, 18 patients (60%) had no AF recurrence without the use of antiarrhythmic drugs. In the remaining 12 patients (40%), AF recurred within 1 week after ablation, and they were treated with class I or class III antiarrhythmic drugs that had been ineffective before ablation and they subsequently had no symptomatic AF episodes. No patients had any symptoms from the PV narrowing. At the second CT scanning, no patients had varied ≥5% in the ratio of the "R-to-P interval" to the "R-to-R interval" compared to the first scanning.

After PV isolation, a de novo luminal reduction was present in 53 ablated PVs (58%; range, 5–46%), and the average severity of the de novo luminal reduction in all 92 ablated PVs, including 39 PVs with no de novo luminal reduction (severity = 0%), was 16 ± 14%. The percent diameter reduction of the de novo luminal reduction was greater in the supero-inferior direction (14 ± 12%) than in the antero-posterior direction (9 ± 13%, P < 0.0001; Table II and Figs. 1B and 5), but the severity of the PV stenosis in the antero-posterior direction was greater than in the supero-inferior direction in 14% of ablated PVs. de novo PV narrowing after ablation was found in 24 PVs (26%; Table II ). It could be detected in both directions in 10 PVs (42%), but was detected only in the supero-inferior direction in the remaining 14 PVs (58%; Fig. 1B). No de novo PV narrowing was found only in the antero-posterior direction. Four PVs which had PV narrowing before ablation demonstrated de novo PV narrowing after ablation. These were all LIPVs, and it occurred at a proximal site to the site with pre-existent PV narrowing in three LIPVs and at the site with pre-existent PV narrowing in the remaining one LIPV.

Relationship between the percent reduction of the supero-inferior diameter and the antero-superior diameter of the PV after ablation. The abbreviations are the same as in Figure 4.

The severity of the de novo luminal reduction was greater and the incidence of the de novo narrowing was higher in the left PVs than the right PVs, and the LIPV had the greatest severity of luminal reduction and the highest incidence of de novo narrowing among the four PVs ( Table II ). The distance between the PV ostium and the site showing the maximal diameter reduction of the de novo luminal reduction was 6.0 ± 3.3 and 5.6 ± 3.2 mm in the coronal and axial sectional views, respectively. The distance between the distal and proximal referential points (length of the luminal reduction) was 9.7 ± 2.2 mm in the supero-inferior direction and 9.8 ± 2.1 mm in the antero-posterior direction.

In the LSPV, RSPV, and LIPV, the supero-inferior and antero-posterior diameters of the PV ostium after ablation were smaller than those before ablation (P < 0.001 for all; Table I ). Both the supero-inferior and antero-posterior percent diameter reductions in the PV ostium correlated with the severity of the de novo luminal reduction (r = 0.31, P < 0.01 and r = 0.30, P < 0.01, respectively). In the 20 non-ablated PVs (19 RIPVs and 1 LIPV), both diameters of the PV ostium after ablation were also smaller than those before ablation (Fig. 6A).

(A) Changes in the supero-inferior and antero-posterior ostial diameters of the nonablated pulmonary veins (PVs). (B) Changes in the trunk length of the ablated and non-ablated PVs. The abbreviations are the same as inFigure 4.

In the ablated PVs, the PV trunk after ablation (12.2 ± 7.6 mm) was shorter than before ablation (13.4 ± 8.1 mm, P < 0.0001; Figs. 3 and 6B). The average percent shortening of the PV trunk was 8.4 ± 10.2% (range, –5% to 34%). Shortening of the PV trunk correlated with the severity of the de novo luminal reduction inside the PV (r = 0.40, P < 0.0005), but it was not related to the percent diameter reduction of the LA (r = 0.15, P = 0.14 for transverse; r = 0.21, P = 0.056 for longitudinal; and r = –0.14, P = 0.22 for antero-posterior percent diameter reduction of the LA). In the non-ablated PVs, the trunk length did not change after ablation (P = 0.07; Fig. 6B).

The LA diameters after ablation were smaller than those before ablation (P < 0.005, for each; Table I ). The supero-inferior percent diameter reduction of the ostium in the ablated PVs (r = 0.30, P < 0.005), as well as in the nonablated PVs (r = 0.53, P < 0.05), correlated with the supero-inferior percent diameter reduction of the LA. The reductive luminal alteration at the ablation site derived from the estimated ablation site before ablation (average, 23 ± 15%; range, –5% to 65%) correlated not only with the supero-inferior percent diameter reduction inside the PV (r = 0.46; P < 0.001) but also with the percent diameter reduction of the LA (r = 0.43; P < 0.001).

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