Conduction Recovery After Pulmonary Vein Isolation for Atrial Fibrillation

Prolonged PR interval and risk of recurrence of atrial fibrillation after catheter ablation

It has been demonstrated that a prolonged PR interval is associated with an increased risk of AF. However, the impact of a prolonged PR interval on recurrence of paroxysmal atrial fibrillation (AF) after catheter ablation is not clear. A total of 112 patients with a prolonged PR interval (PR > 200 ms) (PPR group) and 112 age- and gender-matched control patients (on a 1:1 basis) with a normal PR interval (NPR group) were included in this study. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting more than 30 seconds beyond 3 months after catheter ablation in the absence of any antiarrhythmic treatment. During a mean follow-up period of 10.9 ± 5.5 months (range, 3-18 months), 61 patients (27.2%) developed recurrence of AF. The recurrence rate was higher in the PPR group than in the NPR group (33.9% versus 20.5%, respectively; P = 0.018). Cox regression analysis with adjustment for age, body mass index, valvular heart disease, left atrial diameter, and pulmonary vein isolation identified only a prolonged PR interval as an independent predictor of recurrence of AF (hazard ratio, 1.81; 95% confidence interval, 1.07-3.05; P = 0.027). Patients with a prolonged PR interval were at an increased risk of AF recurrence after catheter ablation.

Reduction of P-Wave Duration and Successful Pulmonary Vein Isolation in Patients with Atrial Fibrillation

INTRODUCTION

We hypothesize that successful pulmonary vein (PV) isolation can shorten the P-wave duration in patients with atrial fibrillation (AF).

METHODS AND RESULTS

We recorded magnified surface electrocardiogram (ECG) and P-wave signal-averaged ECG using 12 electrode leads before and after 31 PV isolation procedures in 27 patients with AF. The patients were followed for 16 +/- 4 months. Repeat ablation studies documented failed PV isolation in seven patients with AF recurrences. At baseline, the maximal P-wave duration in patients without AF recurrence (161 +/- 7 msec) was slightly shorter than that in patients with AF recurrence (168 +/- 10 msec, P < 0.05). After ablation, patients without recurrence showed a significant reduction of P-wave duration from 161 +/- 7 msec to 151 +/- 8 msec (P < 0.0001). In contrast, no change of P-wave duration was noted in patients with recurrences. These findings were confirmed with signal averaged ECG of the P-waves. Three-dimensional (3-D) computer simulation using an atrial cell model showed that elimination of the muscle sleeves inside the PV resulted in a shortening of the P-wave duration and change of the terminal portion of the P-wave morphology.

CONCLUSIONS

A significant shortening of P-wave duration by P-wave signal-averaged ECG can be used as an indicator for successful PV isolation. These findings suggest that activation of the PV muscle sleeves may be an important component of the terminal portion of the P-wave on surface ECG.

Pilsicainide for atrial fibrillation

Pilsicainide is a class IC antiarrhythmic drug, which has a pure sodium channel blocking action with slow recovery pharmacokinetics. In experimental studies, pilsicainide has a depressant effect on intra-atrial conduction and a prolonging effect on the atrial effective refractory period (ERP). In patients with paroxysmal atrial fibrillation (AF), pilsicainide significantly prolonged the ERP of the distal pulmonary vein (PV), PV-left atrium (LA) junction and LA, and the conduction time from the distal PV to the PV-LA junction. In some patients, PV-LA conduction block has been observed just before pilsicainide-induced termination of AF; this isolation of the PV may provide a new insight into the mechanism of pharmacological conversion of AF. Hybrid therapy with pilsicainide and PV isolation (by radiofrequency catheter ablation) appears to be an effective therapeutic approach for AF. The pharmacological PV isolation by pilsicainide and its suppression of focal discharges from atrial tissue may prevent the development of AF after unsuccessful ablation.

Segmental Pulmonary Vein Antrum Isolation Using the "Large-Size" Lasso Catheter in Patients With Atrial Fibrillation

BACKGROUND

The limited efficacy and complications of segmental ostial pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have been discussed so, in the present study the feasibility and efficiency of performing segmental pulmonary vein (PV) antrum isolation to treat AF were assessed.

METHODS AND RESULTS

A total of 187 patients with drug-refractory AF (paroxysmal 120, persistent 67) underwent segmental PVI guided by circumferential 20-electrode catheters (Lasso). Radiofrequency (RF) current was delivered either at the ostium using a regular Lasso (15-20 mm in diameter, 70 patients: Group 1) or at the antrum using a larger Lasso (25-30 mm in diameter, 117 patients: Group 2). A significantly wider region had to be ablated, with a longer RF application time, to isolate all 4 PVs in Group 2 patients than in Group 1 patients. Although the rate of recurrence of AF after the initial session was equal in both groups, a significantly greater number of patients were free from AF after a mean of 1.4 procedures in Group 2 than in Group 1 (93% vs 76% for paroxysmal AF, 78% vs 48% for persistent AF).

CONCLUSIONS

Segmental antral PVI using large-sized Lasso catheters was found to be more effective and safer than ostial PVI for the treatment of AF.

Is circumferential pulmonary vein isolation preferable to stepwise segmental pulmonary vein isolation for patients with paroxysmal atrial fibrillation?

BACKGROUND

Stepwise segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) have been developed to treat patients with atrial fibrillation (AF), but the preferable approach for paroxysmal AF (PAF) has not been established.

METHODS AND RESULTS

One hundred and ten patients with symptomatic PAF were randomized into a stepwise SPVI group (n=55) or CPVI group (n=55). Systemic SPVI combined with left atrial linear ablation tailored by inducibility of AF was performed in the stepwise SPVI group. Circumferential linear ablation around the left and right-sided pulmonary veins (PVs) guided by 3-dimensional electroanatomic mapping was performed in the CPVI group. The endpoints of ablation are non-induciblity of AF in the stepwise SPVI group and continuity of circular lesions combined with PV isolation in the CPVI group. After the initial procedures, atrial tachyarrhythmis (ATa) recurred within the first 3 months in 23 of the 55 patients (41.8%) who underwent stepwise SPVI and in 20 of the 55 patients (36.4%) who had CPVI (p=0.69). Repeat procedures were performed in 7 patients from the stepwise SPVI group and 5 from the CPVI group (p=0.76). During the 3-9 months after the last procedure, 46 patients (83.6%) from the CPVI group and 43 (78.2%) from the stepwise SPVI group did not have symptomatic ATa while not taking anti-arrhythmic drugs (p=0.63). Severe subcutaneous hematoma or PV stenosis occurred in 3 patients.

CONCLUSIONS

The efficacy of stepwise SPVI is comparable to that of CPVI for patients with PAF.

New Approach to Pulmonary Vein Isolation for Atrial Fibrillation Using a Multielectrode Basket Catheter

BACKGROUND

Pulmonary vein (PV) isolation using a circular catheter creates an entrance block from the left atrium (LA) to the PV, which eliminates paroxysmal atrial fibrillation (PAF). A new approach to PV isolation during distal PV pacing is to use a basket catheter.

METHODS AND RESULTS

Fifty consecutive patients with PAF underwent basket-catheter-guided PV isolation. PV pacing was performed from the distal electrode pair of the basket catheter. The exit breakthrough point was targeted for segmental PV isolation. The endpoint was the elimination of bidirectional PV - LA conduction. A repeat ablation procedure was performed in 12 of 14 patients who had recurrence of AF. The recovery of PV -LA conduction was noted in 24 of the 48 PVs, and 5 PVs (21%) had unidirectional block. At 12 months, 80% of patients were free of AF without antiarrhythmic drugs. No PV stenosis >50% was detected at 12 months after the procedure.

CONCLUSIONS

This new approach for PV isolation during distal PV pacing using a basket catheter is useful for confirming bidirectional PV - LA conduction block. PV isolation that creates not only an entrance block but also an exit block at the PV - LA junction may be required to cure paroxysmal AF.

Percutaneous Transvenous Mitral Commissurotomy and Radiofrequency Catheter Ablation in Patients With Mitral Stenosis Initial Experience and Results

BACKGROUND

The purpose of this study was to evaluate the short- and long-term results of radiofrequency catheter ablation (RFCA) for the treatment of atrial fibrillation (AF) in patients with mitral stenosis (MS) following percutaneous transvenous mitral commissurotomy (PTMC).

METHODS AND RESULTS

Four patients (2 males, age 59+/-6 years) underwent simultaneous PTMC and pulmonary vein (PV) ablation. All patient had AF and MS (2 had persistent AF >1 month, 2 had paroxysmal AF), and the mean duration of AF was 3.4+/-3.3 years. The mean left atrial dimension was 47+/-7 mm and the mean ejection fraction was 58+/-4%. After PTMC, RFCA was performed in all patients (3 underwent PV isolation and 1 had PV focal ablation). The mitral valve area increased from 1.11 +/-0.19 to 1.90+/-0.20 cm(2) (p < 0.01). The frequency of AF episodes was dramatically reduced in the 2 patients with paroxysmal AF, and the 1 with persistent AF maintained sinus rhythm, but 1 patient with persistent AF developed recurrent AF. No complications or cardiac events occurred in any of the patients.

CONCLUSION

The combination of RFCA and PTMC was safe and feasible, and may be useful in patients with MS and AF.

Hybrid Therapy With Pilsicainide and Pulmonary Vein Isolation for Atrial Fibrillation

BACKGROUND

Pulmonary vein (PV) isolation is commonly performed in patients with drug-refractory atrial fibrillation (AF) and in cases of unsuccessful ablation, antiarrhythmic agents that were ineffective before the ablation sometimes become effective afterward. Therefore, the effects and mechanisms of hybrid therapy with pilsicainide and PV isolation for AF were assessed in the present study.

METHODS AND RESULTS

Seventy-four patients with paroxysmal AF in whom pilsicainide was ineffective underwent PV isolation. If AF recurred, a second procedure was performed and if AF recurred again, pilsicainide was re-administered. After the first procedure, AF recurred in 42 patients, and a second procedure was performed in 31 patients, of whom 28 had recovery of left atrial (LA)-PV conduction and non-PV foci were identified in 3. After the second session, ablation eliminated AF without drugs in 53 (72%) patients. Pilsicainide suppressed the conduction properties at the LA-PV junction. In 21 patients with recurrence of AF, pilsicainide was re-administered and eliminated AF in 11 patients (success with pilsicainide: 86%).

CONCLUSIONS

In cases of unsuccessful PV isolation, pilsicainide may prevent AF by modifying the LA-PV conduction properties. Hybrid therapy with pilsicainide and PV isolation may be an effective therapeutic approach for AF.

Comparison of 2 Mapping Strategies for Pulmonary Vein Isolation

BACKGROUND

Pulmonary vein (PV) isolation using a circular catheter (CC) creates an entrance block from the left atrium (LA) to PV to eliminate paroxysmal atrial fibrillation (PAF). We describe a new approach for PV isolation during distal PV pacing using a basket catheter (BC). The purpose of the present study was to compare 2 mapping strategies for PV isolation.

METHODS AND RESULTS

Of 100 consecutive patients with PAF, 50 underwent CC-guided PV isolation and 50 underwent BC-guided PV isolation. During CC-guided ablation, the endpoint was the elimination of PV potentials based on the entrance block from the LA to PV. During BC-guided ablation during distal PV pacing, the endpoint was the elimination of bidirectional PV-LA conduction. At 12 months, 62% of patients who underwent CC ablation and 80% of patients who underwent BC ablation were free of symptomatic PAF without the use of antiarrhythmic drugs (p<0.05). The incidence of mild (<50%) PV stenosis in BC ablation was significantly lower than that in CC ablation (12 vs 24%, p<0.01).

CONCLUSIONS

This new approach for PV isolation during distal PV pacing using BC is useful for confirming a bidirectional PV-LA conduction block and is more effective than CC ablation.