Value of ultrasound for access guidance and detection of subclinical vascular complications in the setting of atrial fibrillation cryoballoon ablation.

AIMS: Vascular complications are the most common complications of atrial fibrillation (AF) ablation. Cryoballoon (CB) ablation for AF needs the insertion of a large 15 Fr sheath in the femoral vein. Our aim was to investigate the impact of vascular ultrasound (US) in guiding access and evaluating post-procedural subclinical complications in a large, multi-centre patient cohort that underwent CB ablation. METHODS AND RESULTS: A total cohort of 1435 consecutive patients were subdivided in 870 US -/-, 265 US -/+, and 300 US +/+ patients depending on US performance for: venipuncture guidance/post-procedural evaluation. Major clinical complications (requiring intervention and/or prolonged stay) were assessed. Irrespective of the clinical status, major US events were systematically determined in the subgroups with US evaluation 1 day post-procedure, if evidence of inadvertent artery puncture/cannulation (communication between artery and collection or artery-vein, regardless of the thrombosis state). Major clinical events were encountered in 1.7% (15/870), 1.1% (3/265), and 0% of patients in US -/-, US -/+, and US +/+ group, respectively (P = 0.02 between US -/- and US +/+ group). In the US -/- group, 5/10 (50%) of pseudo-aneurysms were diagnosed during readmission after a mean of 24 ± 11 days post-procedure. No delayed presentation was seen in the US -/+ group. Major US events during the US protocol post-procedure were seen in 3.8% (10/265) vs. 0.3% (1/300) of patients in US -/+ vs. US +/+ group, respectively, P = 0.004. CONCLUSION: US-guided venipuncture was associated with a near-to-zero risk of vascular complications in our patients undergoing CB ablation.

Over-the-needle trans-septal access using the cryoballoon delivery sheath and dilator in atrial fibrillation ablation.

BACKGROUND: In the setting of second-generation cryoballoon (CB2) ablation, left atrial (LA) access is generally achieved using a standard sheath (SS) that is exchanged for the 15Fr cryoballoon delivery sheath (CBS) and dilator over a long wire (CBS over-the-wire technique, CBS-W). Our objective was to evaluate the direct use of the CBS to gain LA access, by advancing the latter over the trans-septal needle (CBS over-the-needle technique, CBS-N), under transesophageal echocardiographic (TEE) guidance. METHODS: Consecutive patients who underwent CB2 ablation with the CBS-N technique were evaluated for feasibility of gaining LA access using TEE guidance and fluoroscopy views. Complications related to the LA access were compared with a matched CBS-W control group. Subanalysis (30 CBS-W vs 30 CBS-N patients) evaluated time-to-LA of the CBS: time from superior vena cava (with SS vs CBS) to LA insertion of the CBS, after exchange or directly, respectively. RESULTS: LA access could be achieved in all 505 patients of the CBS-N group, without technique modification or additional equipment. Challenging interatrial septa were noted in 13% of these patients: previous atrial septal defect repair (1%), hypermobile (10%), aneurysmal (1%), and abnormally thickened/fibrotic (1%). Incidence of complications was similar to the CBS-W group. Subanalysis showed a shorter time-to-LA in the CBS-N versus CBS-W group, 72 ± 46 seconds versus 293 ± 180 seconds, P < .001. CONCLUSIONS: Our study showed that the CBS-N technique is feasible and safe under echocardiographic guidance. Without sheath exchange, it simplifies the CB2 procedure, is less costly, time sparing, and might reduce the risk of air embolism.

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.

Impact of radiofrequency characteristics on acute pulmonary vein reconnection and clinical outcome after PVAC ablation.

OBJECTIVE: The objective was to study the impact of radiofrequency (RF) characteristics on acute pulmonary vein reconnection (PVR) and outcome after PVAC ablation. PVI with additional ablation of PVR (PVI + PVR) was compared to PVI-only. METHODS: In 40 consecutive patients, after PVAC-guided PVI, adenosine and a 1-hour waiting time were used to unmask and ablate acute PVR (PVI + PVR group). RF-characteristics and 1-year AF freedom were compared post hoc to 40 clinically matched patients undergoing PVI only (PVI-only group). Custom-made software was used to assess RF characteristics of the PVAC applications needed to obtain baseline PVI. RESULTS: There was no difference in clinical characteristics or baseline RF-profile between both groups. Acute PVR was observed and ablated in 38 of 160 veins (24%). AF-freedom after PVI + PVR was higher than PVI (85% vs 65%, P < 0.05). Within the PVI group, comparing patients with and without AF-recurrence, the percentage of PVAC applications with high T° (>48°) but low power (<3W) was higher (28 ± 18% vs 11 ± 11%, P < 0.0001). Within the PVI + PVR group, when comparing PVs with and without PVR, the percentage of low power/high T° PVAC applications was also higher (27 ± 13% vs 13 ± 15%, P < 0.0001). CONCLUSIONS: (1) After PVAC ablation, 24% of PVs exhibit acute reconnection. Additional ablation of reconnection improves clinical outcome. (2) Acute reconnection as well as clinical recurrence of AF are characterized by PVAC ablation with a considerable number of applications with high temperature but low power. (3) If PV isolation is obtained with low power applications, a consistent use of both adenosine and waiting time is required.

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.

The use of ivabradine for inappropriate sinus tachycardia.

We present a 47-year-old woman with inappropriate sinus tachycardia. Initial treatment with beta blockers was not successful. The patient became asymptomatic and tachycardia resolved with ivabradine. In this report we review the potential role of ivabradine in the treatment of inappropriate sinus tachycardia.

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.

Initial experience with the high-density mesh ablation catheter for pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is usually performed with multiple point-by-point radiofrequency ablation with a second multielectrode circular mapping catheter to validate isolation. We evaluated a 30-mm high-density mesh electrode (HDMA) for mapping and PVI in patients with recurrent atrial fibrillation (AF). METHODS: In 13 patients (validation group) up to three pulmonary veins (PVs) were targeted with the HDMA. A circular mapping catheter was used to validate PVI. PVI was completed with a CARTO-guided approach (Biosense Webster, Diamond Bar, CA, USA) followed by a voltage remap. In 11 patients (feasibility group) the HDMA catheter was evaluated as a stand-alone mapping and ablation tool. RESULTS: The diagnostic accuracy of the HDMA catheter to evaluate PVI was 100%. The encircled low-voltage area (<0.15 mV) after HDMA-guided PVI was smaller compared to CARTO-guided PVI. In the feasibility group 76% of the PVs could be isolated. Complete isolation of all PVs was feasible in five patients (45%) with a mean procedure and fluoroscopy time of respectively 180 +/- 39 minutes and 40 +/- 14 minutes. After 1 year 64% of the patients were free of symptomatic AF. CONCLUSIONS: The HDMA electrode is a reliable mapping tool to validate PVI. The majority of PVs can be isolated, but on a patient basis touch-up ablations are necessary in more than 50% of the cases. Therefore, modifications in catheter design are required. The small area of voltage abatement points to an ostial left atrium-pulmonary vein disconnection. Initial clinical results in a small number of patients are promising.

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.

Superior vena cava syndrome and infection of pacing leads in one patient.

The superior vena cava (SVC) syndrome is an uncommon complication due to permanent transvenous pacemaker electrodes. Infection of the leads is a risk factor for its occurrence. After being treated for SVC syndrome, due to multiple pacemaker leads, with thrombolysis and coumarine therapy, our patient was diagnosed with repetitive positive blood cultures. Because of relapsing SVC syndrome all pacemaker material was surgically removed. Recovery was complete and the patient remained pacemaker-independent. Culture of the leads showed the same coagulase-negative staphylococci as in the blood cultures. The indications for pacemaker implantation should always be rigorously defined and complications thoroughly investigated and treated.

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, 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.

No evidence of automatic atrial overdrive pacing efficacy on reduction of paroxysmal atrial fibrillation.

AIMS: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown. METHODS AND RESULTS: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (> or =24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group. CONCLUSIONS: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS.