Mj Earley

Long-term efficacy of catheter ablation for atrial fibrillation: impact of additional targeting of fractionated electrograms

Objectives To investigate long-term efficacy of catheter ablation for atrial fibrillation (AF) and the impact of ablating complex or fractionated electrograms (CFEs) in addition to pulmonary vein isolation and linear lesions in persistent AF (PeAF). Methods Consecutive cases from 2002–2007 were analysed. All the patients underwent a wide-area circumferential ablation with confirmation of electrical isolation. For PeAF, linear lesions were added, with additional targeting of CFE from 2005. Data were collected in a prospective database. Attempts were made to contact all patients for follow-up. Results 285 patients underwent 530 procedures. The mean (SD) age was 57 (11) years, 75% were male, 20% had structural heart disease and 53% had paroxysmal AF (PAF). The mean number of procedures was 1.9 per patient (1.7 for PAF and 2.0 for PeAF). Procedural complications included stroke or transient ischemic attack in 0.6% and pericardial effusion requiring drainage in 1.7%. During 2.7 years (0.2 to 7.4 years) of follow-up from the last procedure, there were seven deaths (unrelated to their ablation or AF) and three strokes or transient ischemic attack (0.3% per year). Freedom from AF/atrial tachyarrhythmia was 86% for PAF and 68% for PeAF. Late recurrence was 3 per 100 years of follow-up after >3 years. The Kaplan–Meier analysis showed that CFE ablation improved the outcome for PeAF after the first cluster of procedures (p=0.049), with a trend towards improved final outcome (p=0.130). Conclusions Long-term freedom from AF is achievable in most patients with PAF and PeAF with low rates of late recurrence. Additional targeting of CFE improves outcome for PeAF. Late adverse events including stroke are few.

Catheter ablation of permanent atrial fibrillation: medium term results

Objective: To investigate the feasibility of catheter ablation as a treatment for symptomatic patients with longstanding permanent atrial fibrillation (AF). Methods: Radiofrequency ablation was applied to encircle all pulmonary veins (PVs) and create lines from the left inferior PV to the mitral valve, along the roof of the left atrium between the PVs, and along the tricuspid valve–inferior vena cava isthmus. A seven day Holter was recorded at discharge and at follow up to assess arrhythmia burden. If patients developed a symptomatic, sustained atrial arrhythmia a repeat ablation procedure was advised. Results: 42 patients underwent the procedure that took a mean of five hours with 50 minutes of fluoroscopy. After a median follow up of 8.4 months, 31 of 41 surviving patients (76%) were in sinus rhythm. Of these, 29 patients were no longer taking any antiarrhythmic drugs but 22 (52%) required more than one procedure. During follow up 49% experienced a sustained atrial tachycardia. Twenty six repeat procedures were performed. Maintenance of sinus rhythm after the first, second, or third procedure was 36% (15 of 42), 58% (11 of 19), and 71% (5 of 7), respectively. From a total of 68 procedures there were two serious complications (2.9%): a stroke from which a full recovery was made, and a PV stenosis. Conclusion: Catheter ablation can be used to cure longstanding permanent AF; however, there is a significant complication rate. Whether this is offset by a mortality benefit associated with sinus rhythm is unknown. Many patients will need more than one procedure to achieve success.

A randomized-controlled trial comparing conventional with minimal catheter approaches for the mapping and ablation of regular supraventricular tachycardias.

AIMS To compare the use of a minimal (MIN) with a conventional (CON) catheter approach for the mapping and ablation of regular supraventricular tachycardias (SVT) and typical atrial flutter (AFL) in the setting of a randomized-controlled trial. METHODS AND RESULTS Two hundred patients (age 51.2 +/- 15.9 years, 99 male) were randomized to a MIN or CON group. The MIN approach involved using two catheters for AFL, one to three for other SVT (ablation catheter included), whereas the CON approach involved three and five catheters, respectively. Acute procedural success was similar between the two groups. There was no significant difference in overall procedure times, fluoroscopy times, or radiation doses. Procedure times were shorter for AFL ablation in MIN compared with CON [60 (30-150) vs. 85 (40-200) min, median (range), P = 0.03] from subgroup analysis. A median of three (one to six) catheters was used in MIN and five (three to seven) in CON (P < 0.0001). Catheter costs were significantly lower in MIN compared with CON [6.1 (2-61) vs. 8.5 (4.4-21.3) units, P < 0.0001, where one unit is equivalent to the cost of a diagnostic quadripolar catheter]. At 6-week follow-up, two patients in MIN (2.1%) and three patients in CON (3.2%) had documented recurrence of the index arrhythmia. CONCLUSION The use of a MIN approach in the treatment of SVT and AFL is as effective, quick, and safe as using a CON approach and is therefore more cost-effective.

Management of thromboembolic risk in persons with haemophilia and atrial fibrillation: is left atrial appendage occlusion the answer for those at high risk?

V. T . F . CHEUNG,*† R. J . HUNTER,*† M. R . GINKS ,*† R. J . SCHILL ING,*† M. J . EARLEY*† and L . BOWLES‡ *Cardiology Department, St Bartholomew’s Hospital, Bart’s Health NHS Trust, London, UK; †NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary, University of London, London, UK; and ‡Haemophilia Centre, The Royal London Hospital, Barts Health NHS Trust, London, UK

THE PREVALENCE OF LEFT ATRIAL APPENDAGE THROMBUS IN PATIENTS UNDERGOING CATHETER ABLATION FOR ATRIAL FIBRILLATION MAINTAINED ON WARFARIN

Introduction Reports of the prevalence of left atrial appendage (LAA) thrombus among patients undergoing catheter ablation for atrial fibrillation (AF) vary and may depend on the anticoagulation regime used prior to the procedure. Methods We undertook transoesophageal echocardiograms (TOE) in 586 patients (age 59.9±0.4 years old, mean±SE, 64.5% male) undergoing catheter ablation for AF who were anti-coagulated on warfarin (international normalised ratio 2–3) for at least 3 consecutive weeks prior to procedure and maintained on warfarin for the procedure itself. Results LAA thrombus was identified in 3 patients from 586 (0.5%) despite all 3 having therapeutic INRs (2.2, 2.2 and 3.3 respectively). None of the remaining patients had a peri-procedural stroke. The three patients with LAA thrombus had CHADS2 scores of ≥1 and CHA2DS2-VASc scores of ≥2. All three patients had impaired left ventricular systolic function (LVSF), and LAA emptying velocities of <40 cm/s (23, 29 and 31 cm/s). Patients with LAA emptying velocities <40 cm/s on TOE (n=111) had significantly (p<0.05) higher CHADS2 (0.9±0.1 vs 0.7±0.001) and CHA2DS2-VASc scores (1.7±0.1 vs 1.4±0.1), and larger LA diameter (4.95±0.09 vs 4.38±0.05 cm, OR for LA >4.6 cm: 2.4, 95% CI 2.13 to 5.41), and were more likely to have impaired LVSF (OR: 2.66, 95% CI 1.52 to 4.66) compared to those with higher velocities on multivariate analysis. Conclusions The prevalence of LAA thrombus using our anticoagulation regime is extremely low. Providing patients have been therapeutically anti-coagulated, pre-operative TOE need only be performed in patients with a CHADS2 score of ≥1/CHA2DS2-VASc score of ≥2 or when LA diameter is >4.6 cm. This criteria has the highest sensitivity (84%) for identifying LAA velocities of <40 cm/s as well as having a sensitivity of 100% for identifying thrombus and also would reduce the number of TOEs performed by 27.7%.

057 A randomised controlled trial of catheter ablation vs medical treatment of atrial fibrillation in heart failure (the CAMTAF trial)

Introduction Although atrial fibrillation (AF) has deleterious effects in patients with heart failure (HF), rhythm control using medication has limited efficacy. Catheter ablation (CA) of AF is effective in restoring sinus rhythm, raising the question: if it can be shown to be safe and effective in HF patients, might it improve left ventricular (LV) function and HF symptoms? We sought to compare the impact of a CA strategy to a medical rate control strategy (MED) in patients with persistent AF and HF. Methods Patients with persistent AF, symptomatic HF, and a LV ejection fraction (EF) <50%, were randomised to CA or MED. HF medication and anticoagulation were optimised prior to baseline observations. For those with recurrent AF in the CA group, a repeat procedure was performed at the end of the 3-month blanking period and follow-up re-started. The primary end-point was the difference in LV EF between groups on echocardiography at 6 months. Echocardiographic data were anonymised and core reported by a blinded collaborating centre. Secondary end-points included difference in NYHA class, Minnesota living with heart failure questionnaire score, and peak oxygen consumption at 6 months. Results 55 patients were randomised, but five were excluded (LV function normalised during optimisation of medications prior to baseline tests in 2, and 3 withdrew un-happy with their treatment allocation). Patients were 58±11 years and 96% were male. Baseline LV EF was 31±10% in the CA group and 33±9% in the MED group. NYHA class was 2.5±0.5 in both groups. Patients underwent 1.6±0.7 procedures. There were two complications: (1) stroke and 1 tamponade. In the CA group 1 patient withdrew after a procedural stroke, and in the MED group 1 patient died. In total 21 of 24 in the MED group and 24 of 26 in the CA group had reached 6-months follow-up and were included in this analysis of the primary end-point. Freedom from AF was achieved in 21/24 (88%) off antiarrhythmic drugs in the CA group, whereas all those in the MED group remained in AF. LV EF in the CA group at 6 months was 39±10% compared to 32±13% in the MED group (p<0.05). NYHA class was also significantly lower in the CA group at 6 months (1.7±0.8 compared to 2.3±0.6 in the medical group; p<0.05). CA was associated with better peak oxygen consumption (22.4±6.3 ml/kg/min vs 18.6±6.0 ml/kg/min, p=0.053) and Minnesota living with heart failure questionnaire score (24±23 vs 48±25, p=0.002) compared to the MED group. Conclusions CA is effective in restoring sinus rhythm in the majority of patients with persistent AF. A CA strategy for patients with AF and HF is associated with improved LV function and heart failure symptoms compared to medical treatment alone.

145 Characterisation of fractionated atrial electrograms critical for maintenance of AF: a randomised controlled trial of ablation strategies (the CFAE af trial)

Introduction Targeting complex fractionated atrial electrograms (CFAE) in the ablation of atrial fibrillation (AF) may improve outcomes, although whether this is by eliminating focal drivers or simply de-bulking atrial tissue is unclear. It is also uncertain what electrogram morphology should be ablated. This randomised study aimed to determine the impact of ablating different CFAE morphologies compared to normal electrograms (ie, de-bulking normal tissue) on the cycle length of persistent AF (AFCL). Methods After pulmonary vein isolation CFAE were targeted systematically throughout the left then right atrium, until termination of AF or abolition of CFAE prior to DC cardioversion. 10 s electrograms were classified by visual inspection according to a validated scale, with Grade 1 being most fractionated and grade 5 normal. Patients were randomised to have CFAE grades eliminated sequentially, from grade 1 to 5 (group 1) or grade 5 to 1 (group 2). Because grade 5 electrograms were considered normal, only 5 were ablated. Mean AFCL was determined manually over 30 cycles from bipolar electrograms recorded at the left and right atrial appendages before and after each CFAE was targeted. Lesions were regarded as individual observations, and a resultant increase in mean AFCL ≥5 ms was regarded as significant. The randomised strategy first controlled for any cumulative effect of ablation on AFCL, and second allowed assessment of the order of ablation on the number of CFAE lesions required. Results 20 patients were randomised. The CFAE grade determined by rapid visual inspection for the 968 electrograms targeted agreed with that at off-line manual measurement in 92.7% (к=0.91). AFCL increased after targeting 49.5% of grade 1 CFAE, 33.6% of grade 2, 12.8% of grade 3, 33.0% of grade 4, and 8.2% of grade 5 CFAE (p<0.0001 for grades 1, 2, and 4 vs 5, 3 vs 5 not significant). Binary logistic regression confirmed the effect of CFAE grade, but showed no effect of electrogram amplitude, location in the left or right atrium, or the order in which CFAE were targeted. There was no difference between groups in the number of grade 1 or 2 CFAE encountered, but there were fewer grade 3 and 4 CFAE in group 2 than group 1 (both p<0.01), translating to fewer CFAE targeted per patient in group 1 compared to group 2 (37±14 and 58±18 respectively; p=0.015). Conclusion Targeting CFAE is not simply atrial de-bulking. Ablating certain grades of CFAE caused AFCL prolongation, suggesting they are more important in maintaining AF. Targeting these CFAE may reduce unnecessary left atrial destruction. (ClinicalTrials.gov number, NCT00894400).Abstract 145 Figure 1 Impact of CFAE grade on the proportion of lesions causing AF cycle length prolongation.

135 Combined radiofrequency and cryoablation for paroxysmal atrial fibrillation. A novel technique to reduce recurrences: Abstract 135 Table 1

Introduction We hypothesised that electrical isolation of the pulmonary veins (PV) by wide area circumferential ablation with radiofrequency (RFA) followed by selective PV ostial ablation using a cryoablation balloon (Cryo) would create parallel lines of block and reduce the incidence of PV reconnection.This would therefore improve first time success rates for paroxysmal atrial fibrillation (PAF). Methods A retrospective study examined 59 consecutive patients undergoing first time PV isolation for symptomatic PAF(>1 year) and had failed at least two medical therapies. Patients received RFA alone, Cryo alone or combined RFA (to isolate PVs) followed by Cryo. Patients were followed up with 12 lead ECG, 7 day Holter monitoring and clinical review. Any atrial arrhythmia lasting greater than 30 s during a 3 month follow-up period was documented as a recurrence. Results Significantly fewer patients had symptomatic palpitations (with documented PAF) in the combined group, with a trend towards need for less redo procedures (Abstract 135 table 1). Complications were one phrenic nerve palsy and one haematoma in the Cryo group, one grounding plate burn in the RF group and one phrenic nerve palsy , one pericardial effusion and one haematoma in the combined group. Total procedure time was greater in the combined group (Abstract 135 table 1). Abstract 135 Table 1 Cryo only (n=13) RFA Only (n=23) RFA and Cryo (n=23) p value Age (years) 55±12 56±10 55±12 NS Male 8(61%) 13(57%) 19(83%) NS Hypertension 3(23%) 7(30%) 7(30%) NS Diabetes mellitus 0(0%) 2(9%) 0(0%) NS Coronary disease 1(8%) 0(0%) 1(4%) NS Left ventricular dysfunction 1(8%) 3(13%) 0(0%) NS Procedure length (min) 171±51 198±65 243±79 0.010 Fluoroscopy time (min) 38±16 29±14 38±19 0.141 Complications 2(15%) 1(4%) 3(13%) NS Median Follow up time in days (IQR) 83(67–189) 99(87–119) 97(80–121) NS Recurrent symptoms requiring medication or redo 6(46%) 10(44%) 3(13%) 0.041 Repeat procedure performed 5(38%) 7(30%) 3(13%) NS Conclusion Preliminary results suggest that combination of RF and Cryoablation is superior to either alone. A prospective randomised trial is underway to confirm these findings.

136 Long term efficacy of catheter ablation for AF: impact of additional targeting of fractionated electrograms

Introduction Published long term follow-up data for catheter ablation (CA) of AF is scarce. Although many centres perform ablation of complex fractionated electrograms (CFE) in addition to pulmonary vein isolation (PVI), evidence for this is conflicting. We sought to investigate long term efficacy of CA for AF and the impact of ablating CFE in addition to PVI and linear lesions in persistent AF (PeAF). Methods Consecutive cases from 2002 to 2007 at St Bartholomews Hospital were analysed. All patients underwent wide area circumferential ablation with confirmation of electrical isolation. For PeAF linear lesions were added at the roof and mitral isthmus, with additional targeting of CFE from 2005. Data were collected in a prospective database. Attempts were made to contact all patients for follow-up in September 2009. Failure was defined as documented recurrence of AF or other atrial tachyarrhythmia (AT) lasting ≥30 s. As repeated procedures for patients with recurrence of AF/AT can distort patterns of late recurrence, this was analysed following the first cluster of procedures defined as when the patient first emerged from their 3 month blanking period free of AF/AT (or failure accepted), that is, when AF was first successfully eliminated whether after one CA or several. Results Two hundred eighty-five patients underwent 530 procedures. Mean age was 57±11 years, 75% male, 20% had structural heart disease and 53% paroxysmal AF. Left atrial diameter was 4.3±0.8 cm and 17% had left ventricular systolic dysfunction. Mean number of procedures was 1.9 per patient (1.7 for PAF and 2.0 for PeAF). Procedural complications included stroke or TIA in 0.6% (all of which resolved) and pericardial effusions which were drained without sequelae in 1.7%. There were no peri-procedural deaths. Of 285 patients, 270 were contacted for follow-up. During 3.3 (2.4 to 7.5) years from the first procedure, there were seven deaths (unrelated to their ablation or AF) and three strokes or TIA (0.3% per year). Freedom from AF/AT at 2.7 (0.2 to 7.4) years after the last procedure was 86% for PAF and 68% for PeAF. Most recurrence occurred in the first year, with late recurrence >3 years occurring in 3/100 years of follow-up. Kaplan–Meier analysis showed that CFE ablation improved outcome for PeAF after the first cluster of procedures (p=0.04), with a trend towards improved final outcome (p=0.13). Conclusion Long term freedom from AF is achievable in the majority of patients with PAF and PeAF with low rates of late recurrence. Rates of periprocedural complications are low, and late adverse events including stroke are few. Targeting CFE in addition to PVI and linear lesions improves outcome for PeAF.

133 A randomised controlled trial of catheter ablation of atrial fibrillation comparing manual and robotic navigation: experience with the hansen robotic system

Introduction Catheter ablation of atrial fibrillation (AF) is technically challenging. Robotic catheter ablation with the Hansen Sensei system aims to improve outcome through improved tissue contact and catheter stability while reducing fluoroscopy and operator fatigue. We present data from the first randomised controlled trial comprising patients with both paroxysmal and persistent AF. Method Patients undergoing first time AF ablation were randomised to robotic or manual catheter ablation. Using a 3D mapping system (St Jude NavX), all patients underwent wide area circumferential ablation (WACA). For persistent AF further lesions were delivered (roof line, CS lines, complex fractionated electrograms). Patients underwent clinic review at 3 months with assessment of symptoms and 12 lead ECG. Data are presented as mean±SD. p<0.05 is significant. Results Hundred patients (mean age 57±10) with AF were randomised. Total procedure times were not prolonged with the robotic approach in either paroxysmal (PAF) or persistent (PERS) AF (PAF: Robot 247±64 and Manual 218±66 min; p=0.2; PERS AF: Robot 328±66 and Manual 315±80 min; p=0.4). Total fluoroscopy time was lower with robotic ablation in persistent AF cases but not PAF (PAF: Robot 49±26 and Manual 49±26 min; p=0.75; PERS AF: Robot 53±22 and Manual 81±30 min; p<0.01). Comparable rates of pulmonary vein isolation were achieved (96% and 98%; p=NS), and rates of PV re-connection at the end of the case were also similar (22.2% and 23.0%, p=NS). The ablation catheter tip dislodged less frequently during robotic cases (2.0±1.9 and 8.9±7; p<0.0001) suggesting improved stability. However, a trend was noted that suggests fewer patients with persistent AF may be ablated to sinus rhythm with the robot (22% vs 48%; p=0.07). Major complication rates were 8.8% (one death, two tamponades, one retroperitoneal bleed) for robotic ablation and 4.2% (one tamponade, one CVA) for manual (p=NS), possibly reflecting a learning curve when using the robotic approach. At 3 month follow-up no significant difference was seen between groups in the following parameters: (1) symptom improvement (PAF: Robot 84% and Manual 86%; p=NS; PERS AF: Robot 71% and Manual 74%; p=NS) (2) anti-arrhythmic drug use (PAF: Robot 20% and Manual 26%; p=NS; PERS AF: Robot 35% and Manual 35%; p=NS) (3) 90 day procedural success as defined by sinus rhythm at follow up, with no documented atrial arrhythmias and no symptoms suggestive of continuing arrhythmia (PAF: Robot 80% and Manual 71%; p=NS; PERS AF: Robot 48% and Manual 65%; p=NS). Conclusions Acute procedural success and 3 month outcome following AF ablation using Robotic catheter navigation are equivalent to those achieved with manual. Fluoroscopy times are reduced in persistent AF cases.