Pulmonary vein isolation of symptomatic refractory paroxysmal and persistent atrial fibrillation: A single centre and single operator experience in the Netherlands

A Model Incorporating Left Ventricular Impedance Index may be Explanatory for Late Pulmonary Vein Isolation Failure

OBJECTIVE

To study the influence of a flow-based Impedance Index to attempt to explain the persistent late failure rate of Pulmonary Vein Isolation (PVI) in patients with Atrial Fibrillation (AF).

BACKGROUND

We recently described a flow-based Impedance Index for left ventricular ejection into the aorta and noted an association with Major Adverse Cardiovascular Event Rate (MACE). While the Impedance Index is not routinely measured in PVI patients it approximates to measures derivable from the left ventricular ejection fraction (EF). We sought to assess the Impedance Index's influence on PVI failure rate in combination with indices of left atrial size.

METHODS

In AF patients (n=100) undergoing a Cardiovascular Magnetic Resonance (CMR) imaging examination prior to undergoing PVI we assessed baseline characteristics for their influence on the PVI failure rate at 3-12 months. Uni-variable and multi-variable binary logistic models were performed to find predictors of the PVI failure rate at follow-up.

RESULTS

All patients underwent PVI and CMR imaging. A total of 26 (26%) patients had late AF recurrence at 3-12 months follow-up. Multi-variable models that predicted PVI failure were: 1) the baseline Impedance Index and LA volume index (p<0.05) and 2) the baseline Impedance Index and the degree of mitral valve regurgitation (MR) (p<0.001). While the Impedance Index was derived from EF, EF per se was not a predictor of PVI failure (p=0.28).

CONCLUSIONS

We have provided evidence of the influence of a flow-based Impedance Index on the PVI late failure rate which is significant and remains explanatory when adjusting for measures of atrial size, MR grade and LA volume index. Direct measure of the Impedance Index was not available here and was derived from EF measures. Further work is needed to directly measure the Impedance Index in a PVI population and determine the mechanism for the influence on PVI failure, which may lead to modification of the ablation procedure to improve the success rate.

Pulmonary vein remodeling following pulmonary vein isolation in patients with atrial fibrillation-do pulmonary veins represent only an epiphenomenon? A cardiac MRI study

Background

After successful pulmonary vein isolation (PVI) for atrial fibrillation (AF), the left atrium (LA) undergoes reverse remodeling. However, few studies have directly studied pulmonary vein (PV) remodeling and focused on whether pre PVI-PV conditions could predict outcome of the procedure. We hypothesize that: (I) post PVI, in addition to LA remodeling the PVs undergo a parallel degree of remodeling; and (II) that PV characteristics pre PVI can be used to identify patients more likely to sustain normal sinus rhythm (NSR).

Methods

Patients (n=100) scheduled for PVI had a cardiovascular magnetic resonance (CMR) imaging before and 6±2 months following PVI. PV cross sectional areas (CSA) within 0.5 cm of the ostium and LA volumes were measured. Patients were categorized as responders (R) or non-responders (NR), based on two separate 14-day Holter monitoring.

Results

PVs CSA were significantly reduced post procedure in both groups, R (233±53 to 192±52 mm², P<0.001) and NR (241±54 to 207±44 mm², P<0.001), however, the difference between R and NR post PVI was not significant (192±52 to 207±44 mm², P=0.19). Reduction in PVs CSAs post procedure moderately correlated with the 3D LA volume reduction (r=0.48, P<0.001).

Conclusions

PVs mirror the LA in that they significantly change in size following PVI yet they were not found to directly predict maintenance of NSR.

Obesity is associated with impaired long-term success of pulmonary vein isolation: a plea for risk factor management before ablation

Aims

Obesity is an increasing health problem and is an important risk factor for the development of atrial fibrillation (AF). We investigated the association of body mass index (BMI) on the safety and long-term efficacy of pulmonary vein isolation (PVI) for drug-refractory AF.

Methods

414 consecutive patients who underwent transcatheter PVI for AF between 2003 and 2013 were included. Successful PVI was defined as absence of atrial arrhythmia on Holter monitoring or ECG, without and with antiarrhythmic drugs during follow-up. Obesity was defined as BMI≥30 kg/m².

Results

Mean age was 56±10 years, 316 (76%) were male, 311 (75%) had paroxysmal AF and 111 (27%) were obese. After a mean follow-up of 46±32 months (1590 patient-years), freedom from atrial arrhythmia and antiarrhythmic drugs was significantly lower in patients with obesity compared with non-obese patients (30% vs 46%, respectively, P=0.005, log-rank 0.016). With antiarrhythmic drugs, freedom from atrial arrhythmia was 56% vs 68% (P=0.036). No differences in minor and major adverse events were observed between patients with obesity and non-obese patients (major 6% vs 3%, P=0.105, and minor 5% vs 5%, P=0.512). Sensitivity analyses demonstrated that BMI (as continuous variable) was associated with PVI outcome (HR 1.08, 95% CI 1.02 to 1.14, P=0.012).

Conclusion

Obesity is associated with reduced efficacy of PVI for drug-refractory AF. No relation between obesity and adverse events was found.

Pulmonary vein isolation of symptomatic refractory paroxysmal and persistent atrial fibrillation: A single centre and single operator experience in the Netherlands

Aim. To investigate long-term outcome and to determine predictors of successful pulmonary vein isolation (PVI) in patients with symptomatic paroxysmal or persistent atrial fibrillation (AF) who are refractory or intolerant to antiarrhythmic drugs.Background. The treatment of AF has traditionally been pharmacological aimed at rate or rhythm control. However, rhythm control remains difficult to establish. PVI is reported to be effective in selected patient groups.Methods. Ninety-nine consecutive patients with a mean age of 54+/-10 years who had paroxysmal or persistent AF were treated in the University Medical Center Groningen. All patients underwent PVI by the same electrophysiologist. Successful PVI was defined as absence of AF on Holter or electrocardiogram (ECG), and no symptoms of AF.Results. After six months of follow-up, 60 (61%) patients were free of AF episodes, both on 96-hour Holter monitoring and on ECGs, and had no symptoms related to AF. Thirty-nine of these 60 patients (65%) were no longer treated with any class I or III antiarrhythmic drugs. Independent determinants of successful PVI were paroxysmal AF (OR 18 [3.5-93], p=0.001), and left pulmonary vein ablation time >55 minutes (OR 15 [2.7-81], p=0.002). Left atrial (parasternal view 42+/-6 vs. 40+/-5 mm, p<0.05 and apical view 61+/-9 vs. 58+/-8 mm, p<0.05) and right atrial (59+/-7 vs. 56+/-5 mm, p<0.05) sizes decreased significantly in the successfully treated patients after six months of follow-up.Conclusion. Independent determinants of a successful outcome after PVI are paroxysmal AF and a longer left atrial ablation time. (Neth Heart J 2009;17:366-72.).