Non-invasive assessment of pulmonary vein isolation durability using late gadolinium enhancement magnetic resonance imaging.

AIMS: Electrical reconnection of pulmonary veins (PVs) is considered an important determinant of recurrent atrial fibrillation (AF) after pulmonary vein isolation (PVI). To date, AF recurrences almost automatically trigger invasive repeat procedures, required to assess PVI durability. With recent technical advances, it is becoming increasingly common to find all PVs isolated in those repeat procedures. Thus, as ablation of extra-PV targets has failed to show benefit in randomized trials, more and more often these highly invasive procedures are performed only to rule out PV reconnection. Here we aim to define the ability of late gadolinium enhancement (LGE)-magnetic resonance imaging (MRI) to rule out PV reconnection non-invasively. METHODS AND RESULTS: This study is based on a prospective registry in which all patients receive an LGE-MRI after AF ablation. Included were all patients that-after an initial PVI and post-ablation LGE-MRI-underwent an invasive repeat procedure, which served as a reference to determine the predictive value of non-invasive lesion assessment by LGE-MRI.: 152 patients and 304 PV pairs were analysed. LGE-MRI predicted electrical PV reconnection with high sensitivity (98.9%) but rather low specificity (55.6%). Of note, LGE lesions without discontinuation ruled out reconnection of the respective PV pair with a negative predictive value of 96.9%, and patients with complete LGE lesion sets encircling all PVs were highly unlikely to show any PV reconnection (negative predictive value: 94.4%). CONCLUSION: LGE-MRI has the potential to guide selection of appropriate candidates and planning of the ablation strategy for repeat procedures and may help to identify patients that will not benefit from a redo-procedure if no ablation of extra-PV targets is intended.

Progressive and Simultaneous Right and Left Atrial Remodeling Uncovered by a Comprehensive Magnetic Resonance Assessment in Atrial Fibrillation.

Background Left atrial structural remodeling contributes to the arrhythmogenic substrate of atrial fibrillation (AF), but the role of the right atrium (RA) remains unknown. Our aims were to comprehensively characterize right atrial structural remodeling in AF and identify right atrial parameters predicting recurrences after ablation. Methods and Results A 3.0 T late gadolinium enhanced-cardiac magnetic resonance was obtained in 109 individuals (9 healthy volunteers, 100 patients with AF undergoing ablation). Right and left atrial volume, surface, and sphericity were quantified. Right atrial global and regional fibrosis burden was assessed with validated thresholds. Patients with AF were systematically followed after ablation for recurrences. Progressive right atrial dilation and an increase in sphericity were observed from healthy volunteers to patients with paroxysmal and persistent AF; fibrosis was similar among the groups. The correlation between parameters recapitulating right atrial remodeling was mild. Subsequently, remodeling in both atria was compared. The RA was larger than the left atrium (LA) in all groups. Fibrosis burden was higher in the LA than in the RA of patients with AF, whereas sphericity was higher in the LA of patients with persistent AF only. Fibrosis, volume, and surface of the RA and LA, but not sphericity, were strongly correlated. Tricuspid regurgitation predicted right atrial volume and shape, whereas diabetes was associated with right atrial fibrosis burden; sex and persistent AF also predicted right atrial volume. Fibrosis in the RA was mostly located in the inferior vena cava-RA junction. Only right atrial sphericity is significantly associated with AF recurrences after ablation (hazard ratio, 1.12 [95% CI, 1.01-1.25]). Conclusions AF progression associates with right atrial remodeling in parallel with the LA. Right atrial sphericity yields prognostic significance after ablation.

Ablation Lesion Assessment with MRI.

Late gadolinium enhancement (LGE) MRI is capable of detecting not only native cardiac fibrosis, but also ablation-induced scarring. Thus, it offers the unique opportunity to assess ablation lesions non-invasively. In the atrium, LGE-MRI has been shown to accurately detect and localise gaps in ablation lines. With a negative predictive value close to 100% it can reliably rule out pulmonary vein reconnection non-invasively and thus may avoid unnecessary invasive repeat procedures where a pulmonary vein isolation only approach is pursued. Even LGE-MRI-guided repeat pulmonary vein isolation has been demonstrated to be feasible as a standalone approach. LGE-MRI-based lesion assessment may also be of value to evaluate the efficacy of ventricular ablation. In this respect, the elimination of LGE-MRI-detected arrhythmogenic substrate may serve as a potential endpoint, but validation in clinical studies is lacking. Despite holding great promise, the widespread use of LGE-MRI is still limited by the absence of standardised protocols for image acquisition and post-processing. In particular, reproducibility across different centres is impeded by inconsistent thresholds and internal references to define fibrosis. Thus, uniform methodological and analytical standards are warranted to foster a broader implementation in clinical practice.

Cost-effectiveness of implantable cardioverter-defibrillators for primary prevention of sudden cardiac death.

INTRODUCTION AND OBJECTIVES: Implantable cardioverter-defibrillators (ICD) are a cost-effective alternative for secondary prevention of sudden cardiac death, but their efficiency in primary prevention, especially among patients with nonischemic heart disease, is still uncertain. METHODS: We performed a cost-effectiveness analysis of ICD plus conventional medical treatment (CMT) vs CMT for primary prevention of cardiac arrhythmias from the perspective of the national health service. We simulated the course of the disease by using Markov models in patients with ischemic and nonischemic heart disease. The parameters of the model were based on the results obtained from a meta-analysis of clinical trials published between 1996 and 2018 comparing ICD plus CMT vs CMT, the safety results of the DANISH trial, and analysis of real-world clinical practice in a tertiary hospital. RESULTS: We estimated that ICD reduced the likelihood of all-cause death in patients with ischemic heart disease (HR, 0.70; 95%CI, 0.58-0.85) and in those with nonischemic heart disease (HR, 0.79; 95%CI, 0.66-0.96). The incremental cost-effectiveness ratio (ICER) estimated with probabilistic analysis was €19 171/quality adjusted life year (QALY) in patients with ischemic heart disease and €31 084/QALY in those with nonischemic dilated myocardiopathy overall and €23 230/QALY in patients younger than 68 years. CONCLUSIONS: The efficiency of single-lead ICD systems has improved in the last decade, and these devices are cost-effective in patients with ischemic and nonischemic left ventricular dysfunction younger than 68 years, assuming willingness to pay as €25 000/QALY. For older nonischemic patients, the ICER was around €30 000/QALY.

Management of anticoagulation in patients undergoing leadless pacemaker implantation.

BACKGROUND: The Micra transcatheter pacing system (Micra TPS) is often implanted in patients with atrial fibrillation and thus with increased thromboembolic risk. It is unknown whether the use of anticoagulants, associated with the use of a large venous introducer, implies an increased risk of bleeding in this group of patients. OBJECTIVE: The purpose of this study was to assess the incidence of bleeding and thromboembolic complications after Micra TPS implantation with and without therapeutic anticoagulation. METHODS: This single-center observational study included 107 consecutive patients receiving the Micra TPS from 2014 to 2018. At procedure completion, a figure-of-eight suture was placed at the femoral puncture site after sheath withdrawal and was maintained for 24 hours. In patients receiving enoxaparin or new oral anticoagulants, treatment was discontinued 12 or 24 hours before the procedure, respectively, and was reinitiated 4-6 hours postprocedure. In those receiving vitamin K antagonists (VKAs), dosing was not discontinued and the procedure was performed if the international normalized ratio was less than 3. RESULTS: Sixty-four patients (60%) did not receive anticoagulants. Of the 43 (40%) who did, 29 (67%) received VKAs, 8 (19%) received new oral anticoagulants, and 6 (14%) received enoxaparin. Two patients presented hemorrhagic or thromboembolic complications during short-term follow-up: 1 woman receiving VKAs presented hemorrhagic pericardial effusion without tamponade and 1 woman not receiving anticoagulants presented thrombosis of the ipsilateral saphenous vein. CONCLUSION: Bleeding and thromboembolic complications after receiving Micra TPSs are infrequent. The use of anticoagulant therapy, regardless of the type, does not increase the complications associated with the procedure.

Mechanisms of sex differences in atrial fibrillation: role of hormones and differences in electrophysiology, structure, function, and remodelling.

Atrial fibrillation (AF) is the clinically most prevalent rhythm disorder with large impact on quality of life and increased risk for hospitalizations and mortality in both men and women. In recent years, knowledge regarding epidemiology, risk factors, and patho-physiological mechanisms of AF has greatly increased. Sex differences have been identified in the prevalence, clinical presentation, associated comorbidities, and therapy outcomes of AF. Although it is known that age-related prevalence of AF is lower in women than in men, women have worse and often atypical symptoms and worse quality of life as well as a higher risk for adverse events such as stroke and death associated with AF. In this review, we evaluate what is known about sex differences in AF mechanisms-covering structural, electrophysiological, and hormonal factors-and underscore areas of knowledge gaps for future studies. Increasing our understanding of mechanisms accounting for these sex differences in AF is important both for prognostic purposes and the optimization of (targeted, mechanism-based, and sex-specific) therapeutic approaches.

Diagnostic Yield and Economic Assessment of a Diagnostic Protocol With Systematic Use of an External Loop Recorder for Patients With Palpitations.

INTRODUCTION AND OBJECTIVES: To assess the diagnostic yield and cost-effectiveness of a diagnostic protocol based on the systematic use of latest-generation external loop recorders (ELRs) compared with the classic diagnostic strategy for patients with recurrent unexplained palpitations. METHODS: Two cohorts of consecutive patients referred for diagnosis of unexplained palpitations to the outpatient clinic of the arrhythmia unit were compared: a prospective cohort after the implementation of a new diagnostic protocol based on the systematic use of ELRs, and another, retrospective, cohort before the implementation of the protocol. The cost of diagnosis was calculated based on the number of complementary examinations, visits to outpatient clinics, or emergency department visits required to reach a diagnosis, and its costs according the prices published for the local health system. RESULTS: One hundred and forty-nine patients were included (91 in the ELR group, 58 in the control group). The diagnostic yield was higher in the ELR group (79 [86.8%] definitive diagnoses in the ELR group vs 12 [20.7%] in the control group, P < .001). The cost per diagnosis was €375.13 in the ELR group and €5184.75 in the control group (P < .001). The cost-effectiveness study revealed that the systematic use of ELR resulted in a cost reduction of €11.30 for each percentage point of increase in diagnosis yield. CONCLUSIONS: In patients with recurrent unexplained palpitations, evaluation by means of a study protocol that considers the systematic use of a latest-generation ELR increases diagnostic yield while reducing the cost per diagnosis.