Atrial Fibrillation Ablation in Congenital Heart Disease: Therapeutic Challenges and Future Perspectives.

The increasing prevalence of atrial fibrillation (AF) in adults with congenital heart disease raises significant questions regarding its management. The unique underlying anatomic and physiological background further adds to the difficulty in eliminating the AF burden in these patients. Herein, we provide an overview of the current knowledge on the pathophysiology and risk factors for AF in adult congenital heart disease, with a special focus on the existing challenges in AF ablation. Emerging imaging modalities and ablation techniques might have a role to play. Evidence regarding the safety and efficacy of AF ablation in adult congenital heart disease is summarized, especially for patients with an atrial septal defect, Ebstein anomaly of the tricuspid valve, tetralogy of Fallot, and Fontan circulation. Finally, any remaining gaps in knowledge and potential areas of future research are highlighted.

Characterization of the Mechanism and Substrate of Atrial Tachycardia Using Ultra-High-Density Mapping in Adults With Congenital Heart Disease: Impact on Clinical Outcomes.

Background Atrial tachycardia ( AT ) is common in patients with adult congenital heart disease and is challenging to map and ablate. We used ultra-high-density mapping to characterize the AT mechanism and investigate whether substrate characteristics are related to ablation outcomes. Methods and Results A total of 50 AT s were mapped with ultra-high-density mapping in 23 procedures. Patients were followed up for up to 12 months. Procedures were classified to group A if there was 1 single AT induced (n=12) and group B if there were ≥2 AT s induced (n=11 procedures). AT mechanism per procedure was macro re-entry (n=10) and localized re-entry (n=2) in group A and multiple focal (n=6) or multiple macro re-entry (n=5) in group B. Procedure duration, low voltage area (0.05-0.5 mV), and low voltage area indexed for volume were higher in group B (159 [147-180] versus 412 [352-420] minutes, P<0.001, 22.6 [12.2-29.8] versus 54.2 [51.1-61.6] cm2, P=0.014 and 0.17 [0.12-0.21] versus 0.26 [0.23-0.27] cm2/mL, P=0.024 accordingly). Dense scar (<0.05 mV) and atrial volume were similar between groups. Acute success and freedom from arrhythmia recurrence were worse in group B (100% versus 77% P=0.009 and 11.3, CI 9.8-12.7 versus 4.9, CI 2.2-7.6 months, log rank P=0.004). Indexed low voltage area ≥0.24 cm2/mL could predict recurrence with 100% sensitivity and 77% specificity (area under the curve 0.923, P=0.007). Conclusions Larger low voltage area but not dense scar is associated with the induction of multiple focal or re-entry AT s, which are subsequently associated with longer procedure duration and worse acute and midterm clinical outcomes.

Catheter ablation vs electrophysiologically guided thoracoscopic surgical ablation in long-standing persistent atrial fibrillation: The CASA-AF Study.

BACKGROUND: Catheter ablation (CA) outcomes for long-standing persistent atrial fibrillation (LSPAF) remain suboptimal. Thoracoscopic surgical ablation (SA) provides an alternative approach in this difficult to treat cohort. OBJECTIVE: To compare electrophysiological (EP) guided thoracoscopic SA with percutaneous CA as the first-line strategy in the treatment of LSPAF. METHODS: Fifty-one patients with de novo symptomatic LSPAF were recruited. Twenty-six patients underwent electrophysiologically guided thoracoscopic SA. Conduction block was tested for all lesions intraoperatively by an independent electrophysiologist. In the CA group, 25 consecutive patients underwent stepwise left atrial (LA) ablation. The primary end point was single-procedure freedom from atrial fibrillation (AF) and atrial tachycardia (AT) lasting >30 seconds without antiarrhythmic drugs at 12 months. RESULTS: Single- and multiprocedure freedom from AF/AT was higher in the SA group than in the CA group: 19 of 26 patients (73%) vs 8 of 25 patients (32%) (P = .003) and 20 of 26 patients (77%) vs 15 of 25 patients (60%) (P = .19), respectively. Testing of the SA lesion set by an electrophysiologist increased the success rate in achieving acute conduction block by 19%. In the SA group, complications were experienced by 7 of 26 patients (27%) vs 2 of 25 patients (8%) in the CA group (P = .07). CONCLUSION: In LSPAF, meticulous electrophysiologically guided thoracoscopic SA as a first-line strategy may provide excellent single-procedure success rates as compared with those of CA, but there is an increased up-front risk of nonfatal complications.

Evaluation of a novel high-resolution mapping system for catheter ablation of ventricular arrhythmias.

BACKGROUND: The mapping of ventricular arrhythmias in humans using a minibasket 64-electrode catheter paired with a novel automatic mapping system (Rhythmia) has not been evaluated. OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of mapping ventricular arrhythmias and clinical outcomes after ablation using this system. METHODS: Electroanatomic maps for ventricular arrhythmias were obtained during 20 consecutive procedures in 19 patients (12 with ventricular tachycardia [VT] and 2 with ventricular ectopy [VE]). High-density maps were acquired using automatic beat acceptance and automatic system annotation of electrograms. RESULTS: Forty-seven electroanatomic maps (including 3 right ventricular and 9 epicardial maps) were obtained. Left ventricular endocardial mapping by transseptal (n = 13) and/or transaortic (n = 11) access was safe with no complications related to the minibasket catheter. VT substrate maps (n = 14; median 10,184 points) consistently demonstrated late potentials with high resolution. VT activation maps (n = 25; median 6401 points) obtained by automatic annotation included 7 complete maps (covering ≥90% of the tachycardia cycle length) in 5 patients in whom the entire VT circuit was accurately visualized. VE timing maps (n = 8) successfully localized the origin of VEs in all, with all accepted beats consistent with clinical VEs. Over a median follow-up of 10 months, no arrhythmia recurrence was noted in 75% after VT ablation and 86% after VE ablation. CONCLUSION: In this first human experience for ventricular arrhythmias using this system, ultra-high-density maps were created rapidly and safely, with a reliable automatic annotation of VT and consistent recording of abnormal electrograms. Medium-term outcomes after ablation were encouraging. Further larger studies are needed to validate these findings.

Left Atrial Appendage Electrical Isolation and Concomitant Device Occlusion to Treat Persistent Atrial Fibrillation: A First-in-Human Safety, Feasibility, and Efficacy Study.

BACKGROUND: Left atrial appendage (LAA) electric isolation is reported to improve persistent atrial fibrillation (AF) ablation outcomes. However, loss of LAA mechanical function may increase thromboembolic risk. Concomitant LAA electric isolation and occlusion as part of conventional AF ablation has never been tested in humans. We therefore evaluated the feasibility, safety, and efficacy of LAA electric isolation and occlusion in patients undergoing long-standing persistent AF ablation. METHODS AND RESULTS: Patients with long-standing persistent AF (age, 68±7 years; left atrium diameter, 46±3 mm; and AF duration, 25±15 months) underwent AF ablation, LAA electric isolation, and occlusion. Outcomes were compared with a balanced (1:2 ratio) control group who had AF ablation alone. Among 22 patients who underwent ablation, LAA electric isolation was possible in 20. Intraprocedural LAA reconnection occurred in 17 of 20 (85%) patients, predominantly at anterior and superior locations. All were reisolated. LAA occlusion was successful in all 20 patients. There were no major periprocedural complications. Imaging at 45 days and 9 months confirmed satisfactory device position and excluded pericardial effusion. One of twenty (5%) patients had a gap of ≥5 mm requiring anticoagulation. Nineteen of twenty (95%) patients stopped warfarin at 3 months. Without antiarrhythmic drugs, freedom from AF at 12 months after a single procedure was significantly higher in the study group (19/20, 95%) than in the control group (25/40, 63%), P=0.036. Freedom from atrial arrhythmias was demonstrated in 12 of 20 (60%) and 18 of 20 (90%) patients after 1 and ≤2 procedures (mean, 1.3), respectively. CONCLUSIONS: Persistent AF ablation, LAA electric isolation, and mechanical occlusion can be performed concomitantly. This technique may improve the success of persistent AF ablation while obviating the need for chronic anticoagulation. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT02028130.

Outcomes and costs of left atrial appendage closure from randomized controlled trial and real-world experience relative to oral anticoagulation.

AIMS: The aim of this study was to analyse randomized controlled study and real-world outcomes of patients with non-valvular atrial fibrillation (NVAF) undergoing left atrial appendage closure (LAAC) with the Watchman device and to compare costs with available antithrombotic therapies. METHODS AND RESULTS: Registry data of LAAC from two centres were prospectively collected from 110 patients with NVAF at risk of stroke, suitable and unsuitable for long-term anticoagulation (age 71.3 ± 9.2 years, CHADS2 2.8 ± 1.2, CHA2DS2-VASc 4.5 ± 1.6, and HAS-BLED 3.8 ± 1.1). Outcomes from PROTECT AF and registry study LAAC were compared with warfarin, dabigatran, rivaroxaban, apixaban, aspirin, and no treatment using a network meta-analysis. Costs were estimated over a 10-year horizon. Uncertainty was assessed using sensitivity analyses. The procedural success rate was 92% (103/112). Follow-up was 24.1 ± 4.6 months, during which annual rates of stroke, major bleeding, and all-cause mortality were 0.9% (2/223 patient-years), 0.9% (2/223 patient-years), and 1.8% (4/223 patient-years), respectively. Anticoagulant therapy was successfully stopped in 91.2% (93/102) of implanted patients by 12 months. Registry study LAAC stroke and major bleeding rates were significantly lower than PROTECT AF results: mean absolute difference of stroke, 0.89% (P = 0.02) and major bleeding, 5.48% (P < 0.001). Left atrial appendage closure achieved cost parity between 4.9 years vs. dabigatran 110 mg and 8.4 years vs. warfarin. At 10 years, LAAC was cost-saving against all therapies (range £1162-£7194). CONCLUSION: Left atrial appendage closure in NVAF in a real-world setting may result in lower stroke and major bleeding rates than reported in LAAC clinical trials. Left atrial appendage closure in both settings achieves cost parity in a relatively short period of time and may offer substantial savings compared with current therapies. Savings are most pronounced among higher risk patients and those unsuitable for anticoagulation.

P wave analysis with wavelets identifies hypertensive patients at risk of recurrence of atrial fibrillation: A case-control study and 1year follow-up.

AIMS: Hypertension is a major risk factor for atrial fibrillation (AF); however, reliable non-invasive tools to assess AF risk in hypertensive patients are lacking. We sought to evaluate the efficacy of P wave wavelet analysis in predicting AF risk recurrence in a hypertensive cohort. METHODS: We studied 37 hypertensive patients who presented with an AF episode for the first time and 37 age- and sex-matched hypertensive controls without AF. P wave duration and energy variables were measured for each subject [i.e. mean and max P wave energy along horizontal (x), coronal (y) and sagittal (z) axes in low, intermediate and high frequency bands]. AF-free survival was assessed over a follow-up of 12.1±0.4months. RESULTS: P wave duration (Pdurz) and mean P wave energy in the intermediate frequency band across sagittal axis (mean2z) were independently associated with baseline AF status (p=0.008 and p=0.001, respectively). Based on optimal cut-off points, four groups were formed: Pdurz<83.2ms/mean2z<6.2µV(2) (n=23), Pdurz<83.2ms/mean2z≥6.2µV(2) (n=10), Pdurz≥83.2ms/mean2z<6.2µV(2) (n=22) and Pdurz≥83.2ms/mean2z≥6.2µV(2) (n=19). AF-free survival decreased (Log Rank p<0.0001) from low risk (Pdurz<83.2ms/mean2z<6.2µV(2)) to high-risk group (Pdurz≥83.2ms/mean2z≥6.2µV(2)). Patients presenting with longer and higher energy P waves were at 18 times higher AF risk compared to those with neither (OR: 17.6, 95% CI: 3.7-84.3) even after adjustment for age, sex, hypertension duration, left atrial size, beta-blocker, ACEi/ARBs and statin therapy. CONCLUSIONS: P wave temporal and energy characteristics extracted using wavelet analysis can potentially serve as screening tool to identify hypertensive patients at risk of AF recurrence.

NGAL and ST2 levels in ambulatory patients with chronic heart failure. Clinical and echocardiographic correlates.

AIM: Neutrophil gelatinase-associated lipocalin (NGAL) and ST2 receptor, a member of the interleukin-1 receptor family, are novel biomarkers with a potential role in the diagnosis and risk stratification of patients with chronic heart failure (CHF). There is however scarce data on their relation with clinical characteristics and cardiac function in patients with CHF. METHODS: Consecutive ambulatory patients with CHF were studied. All patients underwent clinical and echocardiographic assessment, and blood samples were collected for the estimation of ST2 and NGAL serum levels during the same assessment. RESULTS: A total of 76 patients (79% male, mean age: 63 ± 14 years), with CHF and left ventricular ejection fraction of 28 ± 7% were included. Median NGAL was 0.16 (0.09-0.275) mg/L and median ST2 was 0.0125 (0.0071-0.0176) mg/L. No association between NGAL and ST2 was observed. Multivariate analysis revealed tissue Doppler-derived right ventricular systolic velocity as an independent predictor of ST2, and the duration of HF and serum creatinine levels as independent predictors of NGAL. CONCLUSIONS: NGAL levels depend on the renal function and the duration of HF, while ST2 levels are affected by the right but not the left ventricular function and show no association with clinical indices of HF.

Utility of noninvasive arrhythmia mapping in patients with adult congenital heart disease.

Arrhythmia management in patients with adult congenital heart disease (ACHD) is a challenge on many levels, as tachycardic episodes may lead to hemodynamic impairment in otherwise compensated patients even if episodes are only transient. Recently several technical advances, including 3-dimensional (3D) image integration, 3D mapping, and remote magnetic navigation, have been introduced to facilitate curatively intended ablation procedures in patients with ACHD. This review attempts to outline the role of a novel technology of simultaneous, noninvasive mapping in this patient cohort, and gives details of the authors' single-center experience.

Utility of a Novel Rapid High-Resolution Mapping System in the Catheter Ablation of Arrhythmias: An Initial Human Experience of Mapping the Atria and the Left Ventricle.

OBJECTIVES: This study sought to assess the clinical efficacy, safety, and clinical utility of a novel electroanatomical mapping system. BACKGROUND: A new mapping system capable of rapidly acquiring detailed maps based on automatic annotation of thousands of points was recently released for clinical use. This is the first description of its utility in humans. METHODS: The first consecutive 20 cases (7 atrial tachycardia, 8 atrial fibrillation, 3 ventricular tachycardia, and 2 ventricular ectopic beat ablations) were analyzed. The system uses a bidirectional deflectable basket catheter with 64 closely spaced mini-electrodes. It automatically accepts and annotates electrograms when a number of predefined criteria are met. RESULTS: Thirty right atrial maps were acquired in 11 (4 to 15) min, consisting of 7,220 (3,467 to 10,947) points, 22 left atrial maps in 11 (6 to 19) min, consisting of 7,818 (4,379 to 12,262) points and 10 left ventricular maps in 37 (14 to 43) min, consisting of 8,709 (2,605 to 15,514) points. The mini-basket catheter could reach all areas of interest without deflectable sheaths. No embolic events, bleeding complications, or endocardial structure damage were observed. Correction of the automatic annotation was performed in 0.02% of points in 4 of 62 maps. The system revealed re-entry circuits of atrial tachyarrhythmias, identified gaps on linear lesions, and identified and correctly annotated the clinical ventricular ectopic beats and channels of slow conduction within ventricular scar. CONCLUSIONS: The novel automatic mapping system was rapid, safe, and efficacious in mapping a variety of cardiac arrhythmias in humans. Further clinical research is needed to optimize its use in the ablation of complex arrhythmias.

Percutaneous extraction of transvenous permanent pacemaker/defibrillator leads.

BACKGROUND: Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. METHODS: Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA) and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany). RESULTS: Lead extraction was attempted in 59 leads from 36 patients (27 men), mean ± SD age 61 ± 5 years, with permanent pacemaker (n = 25), defibrillator (n = 8), or cardiac resynchronisation therapy (n = 3) with a mean ± SD implant duration of 50 ± 23 months. The indications for lead removal included pocket infection (n = 23), endocarditis (n = 2), and ventricular (n = 10) and atrial lead dysfunction (n = 1). Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4 ± 2 minutes/lead for leads implanted <48 months (n = 38) and 7 ± 3 minutes/lead for leads implanted >48 months (n = 21), P = 0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. CONCLUSIONS: In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe.

Efficacy and safety of high dose versus low dose furosemide with or without dopamine infusion: the Dopamine in Acute Decompensated Heart Failure II (DAD-HF II) trial.

AIMS: The role of low-dose dopamine infusion in patients with acute decompensated heart failure (ADHF) remains controversial. We aim to evaluate the efficacy and safety of high- versus low-dose furosemide with or without low-dose dopamine infusion in this patient population. METHODS AND RESULTS: 161 ADHF patients (78 years; 46% female; ejection fraction 31%) were randomized to 8-hour continuous infusions of: a) high-dose furosemide (HDF, n=50, 20mg/h), b) low-dose furosemide and low-dose dopamine (LDFD, n=56, 5mg/h and 5 µg kg(-1)min(-1) respectively), or c) low-dose furosemide (LDF, n=55, furosemide 5mg/h). The main outcomes were 60-day and one-year all-cause mortality (ACM) and hospitalization for HF (HHF). Dyspnea relief (Borg index), worsening renal function (WRF, rise in serum creatinine (sCr) ≥ 0.3mg/dL), and length of stay (LOS) were also assessed. The urinary output at 2, 4, 6, 8, and 24h was not significantly different in the three groups. Neither the ACM at day 60 (4.0%, 7.1%, and 7.2%; P=0.74) or at one year (38.1%, 33.9% and 32.7%, P=0.84) nor the HHF at day 60 (22.0%, 21.4%, and 14.5%, P=0.55) or one year (60.0%, 50.0%, and 47%, P=0.40) differed between HDF, LDFD, and LDF groups, respectively. No differences in the Borg index or LOS were noted. WRF was higher in the HDF than in LDFD and LDF groups at day 1 (24% vs. 11% vs. 7%, P<0.0001) but not at sCr peak (44% vs. 38% vs. 29%, P=0.27). No significant differences in adverse events were noted. CONCLUSIONS: In ADHF patients, there were no significant differences in the in-hospital and post-discharge outcomes between high- vs. low-dose furosemide infusion; the addition of low-dose dopamine infusion was not associated with any beneficial effects.

General anesthesia versus sedation for implantation of a biventricular pacing device for cardiac resynchronization therapy.

OBJECTIVE: Heart failure carries significant risk for major noncardiac surgery. Whether this risk is transferable to minor surgery is less well-documented. Thus, the aim of this study was to assess the outcome of a contemporary cohort of heart failure patients undergoing cardiac resynchronization therapy (CRT) device insertion under general anesthesia or sedation. DESIGN: Retrospective observational study. SETTING: Tertiary cardiac specialist hospital. PARTICIPANTS: Heart failure patients. INTERVENTIONS: CRT insertion under general anesthesia or sedation. MEASUREMENTS AND MAIN RESULTS: Anesthesia, heart failure, and outcome data were collected on a consecutive series of patients having CRT device insertion between 2002 and 2010. A total of 242 patients were managed by the anesthesia department during the study period. After exclusion criteria were applied, data for 183 patients were analyzed. Immediate perioperative (<24 hours) mortality was zero; 30-day mortality of 138 patients was 2.2%. One patient (0.5%) required unplanned intensive care admission. A comparison was made between the sedation (n = 76) group and the general anesthesia (GA) group (n = 107). When compared with the sedation group, the GA group had more intraoperative hypotension (26.2% versus 4.0%, p<0.00001). There was no difference between the GA and sedation groups with regard to 30-day mortality (1.4% versus 3.1%, p = 0.57), unplanned intensive care admission (0% versus 1.3%, p = 0.42), and length of stay in days (3 versus 3, p = 0.82). CONCLUSION: The authors found that patients with heart failure undergoing CRT insertion with concurrent general anesthesia or sedation had minimal immediate perioperative risk and that there was no difference in postoperative outcome between general anesthesia and sedation.