Shouvik Haldar

A Randomized Trial to Assess Catheter Ablation Versus Rate Control in the Management of Persistent Atrial Fibrillation in Heart Failure

OBJECTIVES This study sought to compare catheter ablation with rate control for persistent atrial fibrillation (AF) in heart failure (HF). BACKGROUND The optimal therapy for AF in HF is unclear. Drug-based rhythm control has not proved clinically beneficial. Catheter ablation improves cardiac function in patients with HF, but impact on physiological performance has not been formally evaluated in a randomized trial. METHODS In a randomized, open-label, blinded-endpoint clinical trial, adults with symptomatic HF, radionuclide left ventricular ejection fraction (EF) ≤35%, and persistent AF were assigned to undergo catheter ablation or rate control. Primary outcome was 12-month change in peak oxygen consumption. Secondary endpoints were quality of life, B-type natriuretic peptide, 6-min walk distance, and EF. Results were analyzed by intention-to-treat. RESULTS Fifty-two patients (age 63 ± 9 years, EF 24 ± 8%) were randomized, 26 each to ablation and rate control. At 12 months, 88% of ablation patients maintained sinus rhythm (single-procedure success 68%). Under rate control, rate criteria were achieved in 96%. The primary endpoint, peak oxygen consumption, significantly increased in the ablation arm compared with rate control (difference +3.07 ml/kg/min, 95% confidence interval: 0.56 to 5.59, p = 0.018). The change was not evident at 3 months (+0.79 ml/kg/min, 95% confidence interval: -1.01 to 2.60, p = 0.38). Ablation improved Minnesota score (p = 0.019) and B-type natriuretic peptide (p = 0.045) and showed nonsignificant trends toward improved 6-min walk distance (p = 0.095) and EF (p = 0.055). CONCLUSIONS This first randomized trial of ablation versus rate control to focus on objective exercise performance in AF and HF shows significant benefit from ablation, a strategy that also improves symptoms and neurohormonal status. The effects develop over 12 months, consistent with progressive amelioration of the HF syndrome. (A Randomised Trial to Assess Catheter Ablation Versus Rate Control in the Management of Persistent Atrial Fibrillation in Chronic Heart Failure; NCT00878384).

Relationship between contact force sensing technology and medium-term outcome of atrial fibrillation ablation: a multicenter study of 600 patients.

Contact force sensing (CFS) technology improves acute pulmonary vein isolation durability; however, its impact on the clinical outcome of ablating atrial fibrillation (AF) is unknown.

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.

Comparison of Robotic and Manual Persistent AF Ablation Using Catheter Contact Force Sensing: An International Multicenter Registry Study

Catheter‐based contact force sensing (CFS) technology gives detailed information regarding contact between the catheter tip and myocardium. This may result in more effective ablation procedures. The primary objective of this study was comparison of remote robotic navigation (RRN) and Manual CFS ablation. The secondary objective was to compare CFS with non‐CFS ablation for both navigation modes.

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.

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.

Impact of stepwise ablation on the biatrial substrate in patients with persistent atrial fibrillation and heart failure.

Background—Ablation of persistent atrial fibrillation can be challenging, often involving not only pulmonary vein isolation (PVI) but also additional linear lesions and ablation of complex fractionated electrograms (CFE). We examined the impact of stepwise ablation on a human model of advanced atrial substrate of persistent atrial fibrillation in heart failure. Methods and Results—In 30 patients with persistent atrial fibrillation and left ventricular ejection fraction ⩽35%, high-density CFE maps were recorded biatrially at baseline, in the left atrium (LA) after PVI and linear lesions (roof and mitral isthmus), and biatrially after LA CFE ablation. Surface area of CFE (mean cycle length ⩽120 ms) remote to PVI and linear lesions, defined as CFE area, was reduced after PVI (18.3±12.03 to 10.2±7.1 cm2; P<0.001) and again after linear lesions (7.7±6.5 cm2; P=0.006). Complete mitral isthmus block predicted greater CFE reduction (P=0.02). Right atrial CFE area was reduced by LA ablation, from 25.9±14.1 to 12.9±11.8 cm2 (P<0.001). Estimated 1-year arrhythmia-free survival was 72% after a single procedure. Incomplete linear lesion block was an independent predictor of arrhythmia recurrence (hazard ratio, 4.69; 95% confidence interval, 1.05–21.06; P=0.04). Conclusions—Remote LA CFE area was progressively reduced following PVI and linear lesions, and LA ablation reduced right atrial CFE area. Reduction of CFE area at sites remote from ablation would suggest either regression of the advanced atrial substrate or that these CFE were functional phenomena. Nevertheless, in an advanced atrial fibrillation substrate, linear lesions after PVI diminished the target area for CFE ablation, and complete lesions resulted in a favorable clinical outcome.

Dynamic inversion time for improved 3D late gadolinium enhancement imaging in patients with atrial fibrillation

High resolution three‐dimensional (3D) late gadolinium enhancement (LGE) imaging is performed with single R‐wave gating to minimize lengthy acquisition durations. In patients with atrial fibrillation (AF), heart rate variability results in variable magnetization recovery between sequence repeats, and image quality is often poor. In this study, we implemented and tested a dynamic inversion time (dynamic‐TI) scheme designed to reduce sequence sensitivity to heart rate variations.

Resolving Bipolar Electrogram Voltages During Atrial Fibrillation Using Omnipolar Mapping

Background: Low-voltage–guided substrate modification is an emerging strategy in atrial fibrillation (AF) ablation. A major limitation to contemporary bipolar electrogram (EGM) analysis in AF is the resultant lower peak-to-peak voltage (Vpp) from variations in wavefront direction relative to electrode orientation and from fractionation and collision events. We aim to compare bipole Vpp with novel omnipolar peak-to-peak voltages (Vmax) in sinus rhythm (SR) and AF. Methods and Results: A high-density fixed multielectrode plaque was placed on the epicardial surface of the left atrium in dogs. Horizontal and vertical orientation bipolar EGMs, followed by omnipolar EGMs, were obtained and compared in both SR and AF. Bipole orientation has significant impact on bipolar EGM voltages obtained during SR and AF. In SR, vertical values were on average 66±119% larger than horizontal (P=0.004). In AF, vertical values were on average 31±96% larger than horizontal (P=0.07). Omnipole Vmax values were 99.9±125% larger than both horizontal (99.9±125%; P<0.001) and vertical (41±78%; P<0.0001) in SR and larger than both horizontal (76±109%; P<0.001) and vertical (52±70%; P value <0.0001) in AF. Vector field analysis of AF wavefronts demonstrates that omnipolar EGMs can account for collision and fractionation and record EGM voltages unaffected by these events. Conclusions: Omnipolar EGMs can extract maximal voltages from AF signals which are not influenced by directional factors, collision or fractionation, compared with contemporary bipolar techniques.

Is bleeding a necessary evil? The inherent risk of antithrombotic pharmacotherapy used for stroke prevention in atrial fibrillation

Current European atrial fibrillation (AF) guidelines have assigned a strong recommendation for the initiation of antithrombotic therapy to prevent thromboembolism in all but those AF patients at low risk (or with contraindications). Furthermore, the selection of antithrombotic therapy is based on the absolute risks of thromboembolism and bleeding, and the relative risk and benefit for a given patient. By their very mechanism of action, antithrombotic agents used for stroke prevention in AF will potentially increase the risk of bleeding events. Moreover, the introduction of novel oral anticoagulation agents have introduced new, hitherto ill-defined, deficiencies in the authors’ knowledge with respect to anticoagulation monitoring, availability of direct antidotes, drug–drug interactions and the ability to appropriately control and reverse their actions if bleeding events occur. The authors present a comprehensive review on all aspects of bleeding related to currently licensed antithrombotic agents used for stroke prevention in patients with AF.