Dirk Stockman

Duty-cycled multi-electrode radiofrequency vs. conventional irrigated point-by-point radiofrequency ablation for recurrent atrial fibrillation: comparative 3-year data

AIMS Pulmonary vein isolation (PVI) is an accepted treatment to relieve symptoms in patients with atrial fibrillation (AF). We studied 3 year outcome after PVI guided by duty-cycled multi-electrode radiofrequency (RF) ablation (pulmonary vein ablation catheter, PVAC) and provided comparative data to outcome after conventional PVI (CPVI) using mapping with irrigated, point-per-point RF ablation. METHODS AND RESULTS One hundred and sixty-one consecutive patients with symptomatic paroxysmal or persistent AF and minimal heart disease underwent PVI (PVAC, n = 79 vs. CPVI, n = 82). Follow-up (with symptom-guided rhythm monitoring) was truncated at 3 years in all patients. Success was defined as freedom of documented arrhythmia after a single procedure and without antiarrhythmic drug treatment (ADT). Baseline characteristics did not differ between both groups. At 3 years follow-up, single-procedure success without ADT was comparable between PVAC and CPVI (65% vs. 55%, P = NS). The majority of recurrences occurred during the first year (PVAC 79% vs. CPVI 70%, P = NS). The annual rate of very late recurrence (i.e. beyond 1 year) was similar in both groups (10.5% vs. 15%, P = NS). CONCLUSION At 3 years follow-up, outcome after PVAC-guided PVI is comparable to conventional isolation by irrigated point-by-point RF ablation. In both strategies, the majority of recurrences occurred in the first year of ablation.

Prevalence, Characteristics, and Predictors of Pulmonary Vein Narrowing After Isolation Using the Pulmonary Vein Ablation Catheter

Background —The risk of pulmonary vein narrowing (PVN) after pulmonary vein isolation (PVI) using a novel multi-electrode ablation catheter (PVAC) is unknown. Methods and Results —Left atrial (LA) volume and PV diameters (PVD) were compared by computed tomography before and 3 months after PVI using duty-cycled phased RF energy (2:1 or 4:1 bipolar/unipolar ratio) in 50 patients. PVD was measured in a coronal and axial view at three levels (A=ostium, B=1cm more distal, C=2cm more distal). Moderate PVN was defined as a PVD reduction of 25-50%, severe PVN as > 50%. LA volume decreased by 12±12% (p<0.01). Axial PVD shortened by a median of 16% (IQR 28% to 5%) , 13% (IQR 25% to 5%) and 9% (IQR 21% to -3%) at level A, B and C respectively (p<0.01 for all); coronal PVD decreased by a median of 6% (IQR 24% to 7%), 11% (IQR 21% to 4%) and 8% (IQR 18% to -2%) (p<0.01 for all). Moderate PVN occurred in 30% of the PVs, in 78% of the patients; severe PVN occurred in 4% of the PVs, in 15% of the patients. PV diameter reduction was not related to changes in LA volume. Conclusions —PVAC ablation results in a consistent moderate reduction of the PV diameters predominantly at the ostium. Severe PVN in 15% of patients raises concerns about the risk for clinical PV stenosis.Background— The risk of pulmonary vein narrowing (PVN) after pulmonary vein isolation, using a novel multi-electrode ablation catheter, is unknown. Methods and Results— Left atrial volume and PV diameters were compared by computed tomography (CT) before and 3 months after pulmonary vein isolation using duty-cycled phased radio frequency energy (2:1 or 4:1 bipolar/unipolar ratio) in 50 patients. Pulmonary vein diameter was measured in a coronal and axial view at 3 levels (A, ostium; B, 1 cm more distal; C, 2 cm more distal). Moderate PVN was defined as a pulmonary vein diameter reduction of 25 to 50%, and severe PVN as >50%. Left atrial volume decreased by 12±12% (P<0.01). Axial pulmonary vein diameter shortened by a median of 16% (interquartile range [IQR] 28 to 5%), 13% (IQR 25 to 5%), and 9% (IQR 21 to −3%) at level A, B, and C, respectively (P<0.01 for all); coronal pulmonary vein diameter decreased by a median of 16% (IQR 24 to 7%), 11% (IQR 21 to 4%), and 8% (IQR 18 to −2%; P<0.01 for all). Moderate PVN occurred in 30% of the PVs, in 78% of the patients; severe PVN occurred in 4% of the PVs, in 15% of the patients. PV diameter reduction was not related to changes in left atrial volume. Conclusions— Isolation of the pulmonary veins using a multielectrode ablation catheter and duty cycled phased radiofrequency energy delivery results in a consistent moderate reduction of the PV diameters predominantly at the ostium. Severe PVN in 15% of patients raises concerns about the risk for clinical PV stenosis.

Prevalence, Characteristics and Predictors of Pulmonary Vein Narrowing after PVAC Ablation

Background —The risk of pulmonary vein narrowing (PVN) after pulmonary vein isolation (PVI) using a novel multi-electrode ablation catheter (PVAC) is unknown. Methods and Results —Left atrial (LA) volume and PV diameters (PVD) were compared by computed tomography before and 3 months after PVI using duty-cycled phased RF energy (2:1 or 4:1 bipolar/unipolar ratio) in 50 patients. PVD was measured in a coronal and axial view at three levels (A=ostium, B=1cm more distal, C=2cm more distal). Moderate PVN was defined as a PVD reduction of 25-50%, severe PVN as > 50%. LA volume decreased by 12±12% (p<0.01). Axial PVD shortened by a median of 16% (IQR 28% to 5%) , 13% (IQR 25% to 5%) and 9% (IQR 21% to -3%) at level A, B and C respectively (p<0.01 for all); coronal PVD decreased by a median of 6% (IQR 24% to 7%), 11% (IQR 21% to 4%) and 8% (IQR 18% to -2%) (p<0.01 for all). Moderate PVN occurred in 30% of the PVs, in 78% of the patients; severe PVN occurred in 4% of the PVs, in 15% of the patients. PV diameter reduction was not related to changes in LA volume. Conclusions —PVAC ablation results in a consistent moderate reduction of the PV diameters predominantly at the ostium. Severe PVN in 15% of patients raises concerns about the risk for clinical PV stenosis.Background— The risk of pulmonary vein narrowing (PVN) after pulmonary vein isolation, using a novel multi-electrode ablation catheter, is unknown. Methods and Results— Left atrial volume and PV diameters were compared by computed tomography (CT) before and 3 months after pulmonary vein isolation using duty-cycled phased radio frequency energy (2:1 or 4:1 bipolar/unipolar ratio) in 50 patients. Pulmonary vein diameter was measured in a coronal and axial view at 3 levels (A, ostium; B, 1 cm more distal; C, 2 cm more distal). Moderate PVN was defined as a pulmonary vein diameter reduction of 25 to 50%, and severe PVN as >50%. Left atrial volume decreased by 12±12% (P<0.01). Axial pulmonary vein diameter shortened by a median of 16% (interquartile range [IQR] 28 to 5%), 13% (IQR 25 to 5%), and 9% (IQR 21 to −3%) at level A, B, and C, respectively (P<0.01 for all); coronal pulmonary vein diameter decreased by a median of 16% (IQR 24 to 7%), 11% (IQR 21 to 4%), and 8% (IQR 18 to −2%; P<0.01 for all). Moderate PVN occurred in 30% of the PVs, in 78% of the patients; severe PVN occurred in 4% of the PVs, in 15% of the patients. PV diameter reduction was not related to changes in left atrial volume. Conclusions— Isolation of the pulmonary veins using a multielectrode ablation catheter and duty cycled phased radiofrequency energy delivery results in a consistent moderate reduction of the PV diameters predominantly at the ostium. Severe PVN in 15% of patients raises concerns about the risk for clinical PV stenosis.

Pulmonary vein stenosis after pulmonary vein ablation catheter–guided pulmonary vein isolation

ase report he patient was a 44-year-old man with highly symptomatic aroxysmal atrial fibrillation (AF). The paroxysms of AF ad started 6 years earlier and initially had been treated with lass IC and Class III antiarrhythmic drugs. He was referred or invasive treatment due to persistent symptomatic AF aroxysms despite medical therapy and after he developed evere side effects of amiodarone treatment (photosensitivty and thyroid dysfunction). No evidence of underlying ardiac disease was noted. Left atrial (LA) diameter on ransthoracic echocardiographic parasternal long-axis view as 44 mm. Contrast-enhanced computed tomography (40 lices, Philips, Eindhoven, The Netherlands) was performed he day before ablation.

Pulmonary vein isolation with the 30 and 35 mm high-density mesh ablator

AIMS To analyse procedural results and clinical outcome of paroxysmal atrial fibrillation (AF) ablation using the 30 and 35 mm high-density mesh ablator (HDMA, Bard Electrophysiology). METHODS AND RESULTS Sixty-four consecutive patients were ablated with the HDMA catheter (26 with the 30 mm, 38 with the 35 mm device). If pulmonary vein (PV) isolation was unsuccessful, ablation was continued using a conventional 4 mm ablation catheter. Success was defined as freedom of AF at 6 months after a single procedure without antiarrhythmic drugs. PV isolation could be obtained in 84/106 (79%) PVs in the 30 mm group vs. 149/153 (97%) PVs in the 35 mm group (P < 0.001). All non-isolated veins were successfully isolated with the conventional 4 mm ablation catheter. Freedom of AF at 6 months was 19% in the 30 mm group vs. 18% in the 35 mm group (P = NS). During a repeat procedure in 19 patients, 69% of the PVs were reconnected with an incremental LA-PV delay of 11 ± 15 ms compared with baseline. CONCLUSION (i) Compared with the 30 mm, the 35 mm HDMA catheter proves to be more efficient in obtaining acute pulmonary vein isolation, (ii) despite these promising procedural results, the clinical outcome is disappointing and (iii) the high reconnection rate and the limited delay in PV potentials suggest that PV isolation with the HDMA catheter is not permanent.

Atrial fibrillation ablation with the second generation cryoballoon: Multicenter propensity score matched comparison between freezing strategies

BACKGROUND Second generation cryoballoon (CB-A) ablation is highly effective in achieving pulmonary vein (PV) isolation and freedom from atrial fibrillation (AF). However, the ideal freezing strategy is still under debate. Our objective was to investigate the efficacy and outcome between different freezing strategies used with the CB-A in a multicenter, matched population. METHODS From a total cohort of 1018 patients having undergone CB-A ablation for drug-refractory AF, 673 patients with follow-up ≥6months were included and stratified according to the applied freezing strategy: bonus freeze (BF) versus single freeze (SF). Final population of 256 BF patients was compared with 256 propensity-score matched SF patients. RESULTS BF strategy consisted of 3 different protocols: 3cycles of 180s; 2cycles of 240s; and cycles of 240s followed by 180s in 99/256 (39%); 42/256 (16%); and 115/256 (45%) patients, respectively. SF approach included cycles of 240s in 23/256 (9%), and 180s in 233/256 (91%) patients. Electrical isolation could be achieved in all PVs by both protocols, with shorter procedure and fluoroscopy times in the SF group (mean 106 vs 65min, and 18 vs 14min, respectively, P<0.001). Phrenic nerve palsy persisted after discharge in a total of 11 patients (2.1%): 4 (1.6%) in the BF group vs 7 (2.7%) in the SF group, P=0.5. AF-free survival was similar between the 2 groups during follow-up (mean 18±10months) (log rank, P=0.6). CONCLUSIONS CB-A ablation showed equal efficacy and outcome between SF and BF strategy.

An Apparent Way of Achieving Proof of Pulmonary Vein Disconnection during Cryoballoon Ablation

Pulmonary vein isolation (PVI) has established itself as a standard therapy for paroxysmal atrial fibrillation (AF). Still, the most widely performed procedure of point‐by‐point distal‐tip ablation using a 3‐dimensional mapping system and a circular catheter to validate PVI remains a complex, elaborative, and time‐consuming procedure. This explains the many efforts being made over the recent years to simplify and shorten PVI procedures without compromising the efficacy or the safety. The cryoballoon (Ablation Frontiers, Medtronic, Inc., Minneapolis, MN, USA) is a recently introduced “single shot ablation tool” to facilitate PVI. Initial studies on efficacy and safety of this device are encouraging in patients with paroxysmal AF. However, several controversies remain, such as the need for an additional circular mapping catheter to validate PVI and the lack of on‐line PV recording during freezes. One of the most recent developments in this field is the Achieve circular mapping catheter (Ablation Frontiers, Medtronic, Inc.). We describe an apparent case in which this tool is used in conjunction with the cryoballoon.

Diagnosis-to-ablation time as a predictor of success: early choice for pulmonary vein isolation and long-term outcome in atrial fibrillation: results from the Middelheim-PVI Registry

Aims The aim of the study is to define long-term outcome of pulmonary vein isolation (PVI) in atrial fibrillation (AF) and to determine whether time window between AF diagnosis and PVI affects outcome. Methods and results Consecutive AF patients undergoing PVI (2006-14) were followed for 5 years. Primary outcome was clinical success, defined as freedom of documented AF without anti-arrhythmic drugs respecting a 1-month blanking period. A 1000 patients were included (age 60 ± 10 years, CHA2DS2-VASc score 1 ± 1). The cohort was divided in four quartiles (Q) according to the diagnosis-to-ablation time (DAT): Q1 DAT 0-11 months (N = 244), Q2 DAT 12-≤33 months (N = 254), Q3 DAT 34-≤70 months (N = 252) and Q4 DAT 71-360 months (N = 250). Mean follow-up was 44.3±21.0 months. At 5 years, clinical success was achieved in 45.2 ± 2.0% of patients. Independent predictors of clinical success were AF type (HR = 0.61; 95%CI 0.50-0.74; P < 0.0001), left atrial size (HR = 1.03; 95%CI 1.02-1.05; P < 0.0001), DAT (HR = 1.00; 95%CI 1.00-1.00; P = 0.001), ablation technique (P = 0.012), and year of ablation (HR = 0.93; 95%CI 0.86-1.00; P = 0.045) in multivariable-adjusted analysis. The highest clinical success was achieved when PVI was performed within the first year, and gradually declined with increasing DAT: 55.9 ± 4.6% for Q1, 46.9 ± 4.0% for Q2, 45.5 ± 3.6% for Q3, and 35.5 ± 3.6% for Q4 (P < 0.001). Conclusion Long-term success rate of PVI is 45.2 ± 2.0%. Shorter diagnosis-to-ablation times are associated with better clinical success. Our data advocate for early PVI following diagnosis of AF.

Retrograde access of the left atrium for pulmonary vein isolation using magnetic navigation after closure of an atrial septum defect

Transseptal puncture is the most commonly used technique to perform electrophysiological procedures in the left atrium. This case report describes a pulmonary vein isolation in a patient with a paroxysmal atrial fibrillation, complicated by the presence of an oversized Amplatzer device (AGA Medical Corp., Golden Valley, MN). A retrograde approach using the magnetic navigation system (Niobe, Stereotaxis Inc., St Louis, USA) was performed, and showed to provide a feasible, safe and successful alternative for catheter ablation of cardiac arrhythmias in patients in whom the classic transseptal approach is impossible.

Complications of pulmonary vein isolation in atrial fibrillation: predictors and comparison between four different ablation techniques: Results from the MIddelheim PVI-registry.

Aims To define predictors of complications of pulmonary vein isolation (PVI) and compare safety between different ablation techniques. Methods and results One thousand patients with atrial fibrillation (AF) (age 60 ± 10, 72% males, CHA2DS2-VASc score 1 ± 1) underwent PVI using various techniques: conventional PVI (CPVI) using mapping with irrigated point-per-point RF ablation (n = 576), multi-electrode RF ablation with the pulmonary vein ablation catheter (PVAC) (n = 272) or high density mesh ablator (HDMA) (n = 59) and cryoballoon (CB) ablation (n = 93). A complication was defined as any procedure-related adverse event resulting in permanent injury or death, requiring intervention or treatment, or prolonging/requiring hospitalization for >48 h. A total of 105 (10.5%) complications occurred in 101 (10.1%) patients. No periprocedural death occurred. Most frequent complications were vascular complications (4%) and pericarditis (3.1%). Seven patients experienced permanent deficit due to PV stenosis (n = 3, 1 CPVI, 2 PVAC) (n = 3) and phrenic nerve palsy (PNP) (n = 4, 3 CPVI, 1 PVAC). Independent predictors of complications were female sex [odds ratio (OR) = 1.73; 95% confidence interval (CI) 1.08-2.79; P = 0.023], CHA2DS2-VASc score (OR = 1.24; 95% CI 1.01-1.52; P = 0.039), and ablation technique (P = 0.006) in multivariable-adjusted analysis. Among the different techniques, CB (P = 0.047) and PVAC ablation (P = 0.003) had lowest overall complication rates. Complication profile (type/severity) differed between techniques (association between CB and PNP, CPVI and pericardial injury, PVAC and transient ischaemic attack/PV stenosis). Conclusion Overall complication rate of PVI with various techniques is 10.5%. Permanent deficit occurred only after PVAC and CPVI in 0.7% of patients. Female sex and a higher CHA2DS2-VASc score increase, while PVAC and CB-PVI decrease, overall risk. Differences in overall safety and individual complication profile make selection of the ablation technique in relation to clinical risk profile possible.