A randomised comparison of Cartomerge vs. NavX fusion in the catheter ablation of atrial fibrillation: The CAVERN Trial

Purpose

Integration of a 3D reconstruction of the left atrium into cardiac mapping systems can aid catheter ablation of atrial fibrillation (AF). The two most widely used systems are NavX Fusion and Cartomerge. We aimed to compare the clinical efficacy of these systems in a randomised trial.

Methods

Patients undergoing their first ablation were randomised to mapping using either NavX fusion or CartoMerge. Pulmonary vein isolation by wide area circumferential ablation was performed for paroxysmal AF with additional linear and fractionated potential ablation for persistent AF. Seven-day Holter monitoring was used for confirmation of sinus rhythm maintenance at 6?months.

Results

Ninety-seven patients were randomised and underwent a procedure. There was no difference in the primary endpoint of freedom from arrhythmia at 6?months (51% in the Cartomerge group vs. 48% in the NavX Fusion group, p?=?0.76). 3D image registration was faster with Cartomerge (24 vs. 33?min, p?=?0.0001), used less fluoroscopic screening (11 vs. 15?min, p?=?0.039) with a lower fluoroscopic dose (840 vs. 1,415?mGyCm², p?=?0.043). There was a strong trend to lower ablation times in the Cartomerge group, overall RF time (3,292?s vs. 4,041, p?=?0.07). Distance from 3D lesion to 3D image shell was smaller in the Cartomerge group (2.7?±?1.9 vs. 3.3?±?3.7?mm, p?Conclusions Cartomerge appears to be faster and uses less fluoroscopy to achieve registration than NavX Fusion, but overall procedural times and clinical outcomes are similar.     

Initial experience of the High-Density Grid catheter in patients undergoing catheter ablation for atrial fibrillation

Purpose

A significant proportion of patients undergoing catheter ablation for atrial fibrillation (AF) experience arrhythmia recurrence. This is mostly due to pulmonary vein reconnection (PVR). Whether mapping using High-Density Wave (HDW) technology is superior to standard bipolar (SB) configuration at detecting PVR is unknown. We aimed to evaluate the efficacy of HDW technology compared to SB mapping in identifying PVR.

Methods

High-Density (HD) multipolar Grid catheters were used to create left atrial geometries and voltage maps in 36 patients undergoing catheter ablation for AF (either due to recurrence of an atrial arrhythmia from previous AF ablation or de novo AF ablation). Nineteen SB maps were also created and compared. Ablation was performed until pulmonary vein isolation was achieved.

Results

Median time of mapping with HDW was 22.3 [IQR: 8.2] min. The number of points collected with HDW (13299.6±1362.8 vs 6952.8±841.9, p<0.001) and used (2337.3±158.0 vs 1727.5±163.8, p<0.001) was significantly higher compared to SB. Moreover, HDW was able to identify more sleeves (16 for right and 8 for left veins), where these were confirmed electrically silent by SB, with significantly increased PVR sleeve size as identified by HDW (p<0.001 for both right and left veins). Importantly, with the use of HDW, the ablation strategy changed in 23 patients (64% of targeted veins) with a significantly increased number of lesions required as compared to SB for right (p=0.005) and left veins (p=0.003).

Conclusion

HDW technology is superior to SB in detecting pulmonary vein reconnections. This could potentially result into a significant change in ablation strategy and possibly to increased success rate following pulmonary vein isolation.

     

Catheter Ablation for Atrial Fibrillation on Uninterrupted Warfarin: Can It Be Done Without Echo Guidance?

AF Ablation on Uninterrupted Warfarin. Introduction: Catheter ablation for atrial fibrillation is an effective treatment for symptomatic patients who have failed drug therapy. Recent studies using intracardiac echocardiography have demonstrated that ablation can be performed safely on uninterrupted warfarin and may be superior to bridging low molecular weight heparin (LMWH). We sought to assess the safety of an uninterrupted warfarin protocol using a simplified ablation protocol in a prospective controlled study. Methods: Two anticoagulation regimes for patients undergoing catheter ablation for atrial fibrillation were evaluated—a bridging LMWH group and an uninterrupted warfarin group. Bleeding complications were compared between the 2 groups. Results: In total 198 patients were evaluated (109 bridging LMWH, 89 uninterrupted warfarin). The preprocedure INR in the LMWH group (mean age 60.6 years, 72% male) was 1.2 ± 0.3 compared to 2.3 ± 0.5 in the uninterrupted warfarin group (mean age 60.9 years, 69% male). The primary outcome (a composite of major and minor bleeding complications) was observed in 78% in the LMWH group compared to 56% in the warfarin group (P = 0.001), mainly due to increased pain at the venous access site (41% vs 16%, P = 0.001). Two patients undergoing ablation on warfarin required pericardiocentesis for cardiac tamponade. Drug costs were lower in the warfarin group ($64.77 ± 31.86 vs $20.76 ± 15.60, P = 0.005), but the overall cost of treatment per patient (including bed occupancy costs) was similar in the LMWH group compared to the warfarin group ($883.96 ± 278.78 vs $816.59 ± 182.72, P = 0.06). Conclusion: Catheter ablation for atrial fibrillation can be performed safely on uninterrupted warfarin without intracardiac echocardiography, with a reduced risk of bleeding complications. (J Cardiovasc Electrophysiol, Vol. 22, pp. 265‐270, March 2011)     

Right atrial angiography facilitates transseptal puncture for complex ablation in patients with unusual anatomy

Objective The number of transseptal punctures performed worldwide has increased exponentially with the development of ablation therapies for atrial arrhythmias. Safe access into the left atrium in these procedures is often complicated by abnormal anatomy. We assessed the potential of right atrial angiography to facilitate transseptal puncture for atrial ablation. Methods and results We examined all transseptal punctures performed for complex left atrial ablation in our centre over a 29-month period. In cases where conventional transseptal techniques failed, we performed orthogonal right atrial angiography to define cardiac anatomy and orientation. During the study period, 255 transseptal procedures were performed. Of these, 16 cases were complicated by distorted atrial anatomy, extreme cardiac rotation or unexpected location of the atria in relation to the diaphragm, preventing left atrial access using conventional fluoroscopy. The application of right atrial angiography facilitated successful transseptal puncture in all patients when use of conventional mapping catheters and fluoroscopy proved unhelpful. There were no complications relating to right atrial angiography. Conclusion These cases highlight a number of difficulties encountered when performing transseptal punctures. Previously reported adjunctive techniques require specialised equipment, general anaesthesia or multiple catheters that may be unavailable or impede the procedure. Right atrial angiography is a simple and safe adjunct to conventional techniques to facilitate complex transseptal procedures.     

Predictors of new onset atrial fibrillation in patients with heart failure

Introduction

Stroke associated with atrial fibrillation (AF) is more frequent in heart failure. It is unknown what variables predict future AF in these patients and how AF might evolve over time. We investigated this in patients with implantable cardiac defibrillators (ICD) where AF detection is optimal.

Methods

Single centre, retrospective, observational cohort study. All ischaemic cardiomyopathy patients with dual chamber, primary prevention ICD implants between Aug 2003 and Dec 2009 were screened and included if at implant, they had no known AF history. Nine variables were analysed. AF was defined as any atrial tachyarrhythmia ≥ 180 bpm and ≥ 30 s. Multivariable, binary logistic regression models were built by adding variables significant in the univariate models. Variables were retained in the final multivariate models if p < 0.05.

Results

n = 197 met the inclusion criteria (85.8% male, median age: 66.8 years). After median follow-up for 2.8 years, 44.2% developed AF. After univariate analysis, the baseline variables associated with AF after implant were age, NYHA class and renal impairment (RI, defined eGFR < 60 ml/min/1.73 m²) (p < 0.05). After multivariable analysis, the only variable which was associated with AF was RI (HR: 2.04 (CI: 1.10–3.79)). Two baseline variables were independently associated with all-cause mortality: RI (HR: 2.42 (1.14–5.12)) and non-white ethnicity.

Conclusion

RI at time of implant was independently associated with both future AF and all-cause mortality during long-term follow-up. RI was a stronger predictor of AF than age. Those patients with heart failure and RI should be regularly screened for asymptomatic AF, regardless of age, to ensure that stroke prophylaxis may be initiated.     

Improved electrogram attenuation during ablation of paroxysmal atrial fibrillation with the Hansen robotic system

Background: Robotic catheter ablation aims to improve outcomes after ablation of atrial fibrillation (AF) through improved lesion quality. This study examined electrogram attenuation as a measure of efficacy in response to robotic (ROB) and manual (MAN) ablation. Methods: Patients with paroxysmal AF undergoing ablation as part of an ongoing randomized controlled trial were studied (Clinical Trials Registration NCT01037296). Patients underwent pulmonary vein isolation using NavX (St. Jude Medical, St. Paul, MN, USA). Patients were randomized to MAN or ROB catheter ablation using a 3.5‐mm irrigated‐tip catheter with standardized ablation settings. Bipolar electrogram voltage was measured at 0, 5, 10, 20, and 30 seconds after ablation onset. Distance from ablation lesion to the left atrial surface on NavX were calculated. Results: Similar ablation energy was delivered in ROB and MAN groups, achieving comparable rates of PV isolation (100% vs 98%). The bipolar voltages of 4,434 electrograms from 303 ablation lesions (146 ROB, 157 MAN) were measured. At 30 seconds, signal attenuation was greater in the ROB group than MAN (mean 65 ± 4% vs 55 ± 4% of baseline voltage, P < 0.01). A total of 2,064 NavX ablation lesions were assessed (906 ROB and 1,158 MAN). ROB lesions were on average 0.52 mm further inside the geometry than MAN (P < 0.0001). Conclusions: Robotic ablation results in greater signal attenuation in man. This is achieved despite manual lesions being closer to the left atrial surface. Catheter stability and constant energy delivery may be key to achieving signal attenuation, rather than increased contact force. (PACE 2012; 35:730–738)