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Aims There is rising healthcare utilization related to the increasing incidence and prevalence of atrial fibrillation (AF) worldwide. Simplifying therapy and reducing hospital episodes would be a valuable development. The efficacy of a streamlined AF ablation approach was compared to drug therapy and a conventional catheter ablation technique for symptom control in paroxysmal AF. Methods and results We recruited 321 patients with symptomatic paroxysmal AF to a prospective randomized, multi-centre, open label trial at 13 UK hospitals. Patients were randomized 1:1:1 to cryo-balloon ablation without electrical mapping with patients discharged same day [Ablation Versus Anti-arrhythmic Therapy for Reducing All Hospital Episodes from Recurrent (AVATAR) protocol]; optimization of drug therapy; or cryo-balloon ablation with confirmation of pulmonary vein isolation and overnight hospitalization. The primary endpoint was time to any hospital episode related to treatment for atrial arrhythmia. Secondary endpoints included complications of treatment and quality-of-life measures. The hazard ratio (HR) for a primary endpoint event occurring when comparing AVATAR protocol arm to drug therapy was 0.156 (95% CI, 0.097–0.250; P < 0.0001 by Cox regression). Twenty-three patients (21%) recorded an endpoint event in the AVATAR arm compared to 76 patients (74%) within the drug therapy arm. Comparing AVATAR and conventional ablation arms resulted in a non-significant HR of 1.173 (95% CI, 0.639–2.154; P = 0.61 by Cox regression) with 23 patients (21%) and 19 patients (18%), respectively, recording primary endpoint events (P = 0.61 by log-rank test). Conclusion The AVATAR protocol was superior to drug therapy for avoiding hospital episodes related to AF treatment, but conventional cryoablation was not superior to the AVATAR protocol. This could have wide-ranging implications on how demand for AF symptom control is met. Trial registration Clinical Trials Registration: NCT02459574.

Aims Radiofrequency ablation creates irreversible cardiac damage through resistive heating and this temperature change results in a generator impedance drop. Evaluation of a novel local impedance (LI) technology measured exclusively at the tip of the ablation catheter found that larger LI drops were indicative of more effective lesion formation. We aimed to evaluate whether LI drop is associated with conduction block in patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein isolation (PVI). Methods and results Sixty patients underwent LI-blinded de novo PVI using a point-by-point ablation workflow. Pulmonary vein rings were divided into 16 anatomical segments. After a 20-min waiting period, gaps were identified on electroanatomic maps. Median LI drop within segments with inter-lesion distance ≤6 mm was calculated offline. The diagnostic accuracy of LI drop for predicting segment block was assessed using receiver operating characteristic analysis. For segments with inter-lesion distance ≤6 mm, acutely blocked segments had a significantly larger LI drop [19.8 (14.1–27.1) Ω] compared with segments with gaps [10.6 (7.8–14.7) Ω, P Conclusion The magnitude of LI drop was predictive of acute PVI segment conduction block in patients with paroxysmal AF. The thinner posterior wall required smaller LI drops for block compared with the thicker anterior wall.

Inadvertent endocardial lead malposition is recognized as a rare incident which is usually underreported and if recognized during implantation can be easily corrected. This phenomenon is caused by the ventricular lead unintentionally crossing a pre-existing patent foremen ovale, septal defects (atrial or ventricular) or directly from the aorta via an accidental subclavian puncture resulting in the lead implanting into the left ventricle. While this is a rare occurrence we report, the incidental finding of pacemaker lead malposition during a routine follow-up transthoracic echocardiogram and the benefits of three-dimensional transesophageal echocardiography in this patient prior to lead extraction.

Objectives A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD). Background The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system’s ability to accurately define the tachycardia circuit. Methods Mapping and ablation data of 61 patients with CHD (35 males, age 45 ± 14 years) from 8 tertiary centers were reviewed. Results Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricular physiology (Fontans) (n = 8); Tetralogy of Fallot (n = 10); atrial septal defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septal resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 ± 8 months, 7 patients had recurrence. Conclusions We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra–high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set.

Atrial Fibrillation (AF) ablation using the cryoballoon is effective at reducing symptomatic AF episodes. The prevalence of AF is increasing with the aging population and access to such treatment would be enhanced by reducing the resource requirements. Relinquishing electrical mapping of the pulmonary veins (PV) removes the need for PV catheters, electrical recording equipment and staff trained in using this equipment. Moreover, the majority of complications are peri-procedural so overnight hospitalization maybe unnecessary. We tested this streamlined approach to AF ablation against medical therapy using the endpoint of time to all hospital episodes. METHODS: The AVATAR-AF study is a prospective, multicenter, randomized controlled trial testing the primary hypothesis that AF ablation done without PV mapping or overnight hospitalization is more effective than anti-arrhythmic drugs at reducing all hospital episodes related to recurrent atrial arrhythmias. We included a third arm to test a secondary hypothesis that confirming PV entrance block as per consensus guidelines can improve outcomes. Three hundred twenty-one patients with documented paroxysmal AF will be randomized in a 1:1:1 manner to one of three investigation arms: (1) AVATAR protocol cryoballoon ablation without assessment of acute PV isolation or overnight hospitalization; (2) medical therapy with anti-arrhythmic drugs; or (3) conventional cryoballoon ablation with assessment of acute PV isolation. The primary endpoint is defined as the time to all hospital episodes (including outpatient consultation) related to treatment for atrial arrhythmia. CONCLUSION: The AVATAR-AF study will determine whether the resource utilization for AF ablation can be reduced whilst maintaining superiority over medical therapy.

This analysis was performed to evaluate the transition of local impedance (LI) drop during pulmonary vein isolation (PVI) to durable block and mature lesion formation based on 3-month mapping procedures.A radiofrequency catheter measuring LI has been shown to be effective for performing PVI in patients with paroxysmal atrial fibrillation. Previous analysis has demonstrated LI drop to be predictive of pulmonary vein segment conduction block during an atrial fibrillation ablation procedure.Fifty-eight patients who had undergone LI-blinded de novo PVI returned for a 3-month mapping procedure. PVI ablation circles were divided into 16 anatomic segments for classification (durable block or gap), and the median LI drop within segments with an interlesion distance of ≤6 mm was compared. A total of 51 data sets met the criteria for segmental analysis of LI performance.At the 3-month procedure, PV connection was confirmed in at least 1 PV segment in 35 of the included patients. LI drop outperformed generator impedance drop as a predictor of durable conduction block (area under the receiver-operating characteristic curve: 0.79 vs 0.68; P = 0.003). Optimal LI drops were identified by left atrial region (anterior/superior: 16.9 Ω [sensitivity: 69.1%; specificity: 85.0%; positive predictive value for durable conduction block: 97.7%]; posterior/inferior:14.2 Ω [sensitivity: 73.8%; specificity: 78.3%; positive predictive value: 96.9%]). Starting LI before radiofrequency (RF) application was significantly different among healthy, gap, and mature scar tissue and was also a contributing factor to achieving an optimal LI drop (85.2% of RF applications with a starting LI of ≥110 Ω achieved the optimal regional drop or greater).LI drop is predictive of durable PV segment isolation. Preablation starting LI is associated with the magnitude of LI drop. These findings suggest that a regional approach to RF ablation guided by LI combined with careful interlesion distance control may be beneficial in patients with paroxysmal atrial fibrillation (Electrical Coupling Information From the Rhythmia HDx System and DirectSense Technology in Subjects With Paroxysmal Atrial Fibrillation [LOCALIZE]; NCT03232645).

OnBehalf United Kingdom Cardiac SABR consortium Background Stereotactic Ablative Body Radiotherapy (SABR) is a novel non-invasive treatment for Ventricular Tachycardia (VT) refractory to standard catheter ablation. 3 UK hospitals have started compassionate use cardiac SABR programmes, and are working in close collaboration. Purpose To report initial UK experience for treatment of refractory VT with cardiac SABR. Methods All patients had undergone prior unsuccessful invasive ablation with VT recurrence despite anti-arrhythmic drug (AAD) use. High-resolution CT imaging with 3D reconstruction was combined with 12 lead ECGs of VT and prior invasive +/- non-invasive electrophysiology mapping data to define a cardiac target. Treatment margins were modified to account for cardiac/respiratory motion and to minimise off target treatment to other organs as per clinical SABR practice. Single fraction high dose treatment (20-25 Gy) was delivered by CT guided Linear Accelerator. Patients were assessed regularly with clinical review and remote device monitoring. Results 3 patients have been treated so far with aetiologies of prior myocarditis, non-ischaemic dilated cardiomyopathy and ischaemic cardiomyopathy. All patients successfully received planned SABR treatment in Conclusions Cardiac SABR shows promise for VT control, but further experience and trials are needed. Integration of imaging and electrophysiology data to generate accurate targets appears critical. The effect of SABR seems to develop over several weeks after therapy. Patient selection and timing of SABR delivery is important with acknowledgement that competing causes of death exist in patients with refractory VT entering a compassionate use program. Abstract Figure. Example SBRT plan

Objective Clinical consultations with patients should be informed by the evidence-based and involve shared decision making (SDM). We aimed to determine the delivery of SDM by clinicians with patients referred for invasive treatment of cardiac electrical disease and to establish whether decisions made corresponded with patient and referring physician expectations. Methods Forty-nine outpatient consultations with two consultant cardiologists in one large tertiary centre were audio-recorded. Demographic data, diagnosis, reasons for referral and decision reached were compared directly with patient and referring physician expectations. The OPTION instrument was used to measure SDM. Patient expectations and satisfaction were elicited. Results Quality of SDM was good (mean OPTION score 49%) and there was broad patient satisfaction. While all patients were suitable for invasive treatment, and the majority (80%, n =39) had been explicitly referred for it, only 59% ( n =29) opted to proceed. Consultation quality with respect to SDM was significantly greater for patients choosing a less invasive option. Conclusion These consultations often change expected management. Where decision making in the consultation is of higher quality, patients were more likely to change to a less invasive option. Practice implications Clinicians performing invasive cardiac treatment should be able to demonstrate high quality decision making.

Ablation for atrial fibrillation is now widespread and may involve the delivery of relatively high doses of ionizing radiation to both patients and operators. Until now, atrial septal puncture has mandated the use of either fluoroscopy or additional expensive imaging modalities for its safe deployment. We describe a novel technique using the EnSite NavX three-dimensional imaging system for visualization of the transseptal needle throughout the puncture-without the need for either fluoroscopy or additional imaging. This may be important in reducing the need for fluoroscopy for left atrial ablation procedures.

Aim Data on arrhythmia outcome following device closure of atrial septal defect (ASD) are lacking. This study provides medium-term follow-up data on atrial arrhythmias in patients who were ≥40 years of age at the time of transcatheter ASD closure. Methods and results It is a retrospective review. Mean age of the 159 patients was 57 years. Median follow-up was 3.6 years (range 6 months–10.9 years). Patients were classified, according to arrhythmia status prior to ASD closure, into Group I, no history of atrial arrhythmia ( n = 119, mean age 55.5 years); Group II, paroxysmal atrial arrhythmia ( n = 18, mean age 55.7 years); and Group III, persistent atrial fibrillation ( n = 22, mean age 65.7 years). Group III patients were significantly older, had larger left atrial size, and had higher mean pulmonary arterial pressure than Group I and II patients ( P < 0.001). Prior to closure, radiofrequency ablation was carried out in 12/18 (66%) of Group II and 3/22 (14%) of Group III. After device closure, 7 patients (6%) of Group I developed new atrial fibrillation. Fifty per cent (9/18) of Group II but only 9% (2/22) of Group III were in sinus rhythm on follow-up. Conclusion Device closure alone in patients with persistent atrial arrhythmia is not likely to restore sinus rhythm in the medium term. New atrial arrhythmia occurred in 6% of patients who were in sinus rhythm prior to device closure. At least 50% of the patients with paroxysmal atrial arrhythmia continue to have significant atrial arrhythmia following device closure, and the role of ablation prior to closure in patients with a history of arrhythmia requires refinement.

Objective To assess the effect of catheter ablation on atrial fibrillation (AF) symptoms and quality of life (QoL). Methods Patients with AF scheduled for ablation were recruited. Pulmonary vein isolation (PVI) was performed and complex fractionated atrial electrogram (CFAE)±linear ablation undertaken in patients in AF despite PVI. QoL and AF symptoms were assessed using SF-36 V2 and Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaires before and 3 months after ablation. Change in QoL scores after ablation was correlated with clinical parameters and the extent of ablation. Magnitude of QoL change was compared between AFEQT and SF-36 physical component summary (PCS) and mental component summary (MCS) scores and correlated with arrhythmia outcome. Results 80 patients were studied. Summative and individual health scores for both AFEQT (51.5±22.0 vs 81.3±18.2; p

Highlights • Individual posterior ECG leads better reflect left atrial activity compared to V1. • Surface dominant AF frequency (DAF) calculated using principal component analysis. • Modified 12-lead ECG (including posterior leads) compared to standard 12-lead ECG. • Surface DAF from modified ECG did not correlate stronger with left atrial activity. • Lead V1 dominant in AF principal component from both ECG configurations., Background Lead V1 is routinely analysed due to its large amplitude AF waveform. V1 correlates strongly with right atrial activity but only moderately with left atrial activity. Posterior lead V9 correlates strongest with left atrial activity. Aims (1) To establish whether surface dominant AF frequency (DAF) calculated using principal component analysis (PCA) of a modified 12-lead ECG (including posterior leads) has a stronger correlation with left atrial activity compared to the standard ECG. (2) To assess the contribution of individual ECG leads to the AF principal component in both ECG configurations. Methods Patients were assigned to modified or standard ECG groups. In the modified ECG, posterior leads V8 and V9 replaced V4 and V6. AF waveform was extracted from one-minute surface ECG recordings using PCA. Surface DAF was correlated with intracardiac DAF from the high right atrium (HRA), coronary sinus (CS) and pulmonary veins (PVs). Results 96 patients were studied. Surface DAF from the modified ECG did not have a stronger correlation with left atrial activity compared to the standard ECG. Both ECG configurations correlated strongly with HRA, CS and right PVs but only moderately with left PVs. V1 contributed most to the AF principal component in both ECG configurations.

Background/objectives Sprint Fidelis and Riata defibrillator leads are prone to early failure. Few data exist on the comparative failure rates and mortality related to lead failure. The aims of this study were to determine the failure rate of Sprint Fidelis and Riata leads, and to compare failure rates and mortality rates in both groups. Methods Patients implanted with Sprint Fidelis leads and Riata leads at a single centre were identified and in July 2012, records were reviewed to ascertain lead failures, deaths, and relationship to device/lead problems. Results 113 patients had Sprint Fidelis leads implanted between June 2005 and September 2007; Riata leads were implanted in 106 patients between January 2003 and February 2008. During 53.0±22.3months of follow-up there were 13 Sprint Fidelis lead failures (11.5%, 2.60% per year) and 25 deaths. Mean time to failure was 45.1±15.5months. In the Riata lead cohort there were 32 deaths, and 13 lead failures (11.3%, 2.71% per year) over 54.8±26.3months follow-up with a mean time to failure of 53.5±24.5months. There were no significant differences in the lead failure-free Kaplan–Meier survival curve (p=0.77), deaths overall (p=0.17), or deaths categorised as sudden/cause unknown (p=0.54). Conclusions Sprint Fidelis and Riata leads have a significant but comparable failure rate at 2.60% per year and 2.71% per year of follow-up respectively. The number of deaths in both groups is similar and no deaths have been identified as being related to lead failure in either cohort.

This 76 year old man had a biventricular implantable cardioverter-defibrillator (ICD) implanted on 14 March 2003 for heart failure and ventricular tachycardia …