Jolien Neefs

Aldosterone Pathway Blockade to Prevent Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND Despite advances in therapeutic interventions AF remains a progressive and symptomatic disease. Therefore, novel therapeutic interventions targeting the underlying arrhythmogenic substrate for AF is needed. Atrial fibrosis is an important component of the arrhythmogenic substrate of AF and may be initiated by aldosterone binding to the mineralocorticoid receptor. We hypothesized that aldosterone pathway blockade with mineralocorticoid receptor antagonists (MRA) reduces atrial fibrosis, and thus AF. METHODS We searched OVID MEDLINE, OVID EMBASE and the Cochrane Central Register of Controlled Trials from inception to June 10th, 2016 for randomized controlled trials (RCT) and observational studies addressing MRA and providing information on AF occurrence. Two independent reviewers selected and appraised the data. We performed random-effects meta-analyses. Summary odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS We included 14 studies, 5 RCT and 9 observational cohorts, with a cumulative number of 5332 patients (male: 74.9%, age: 65.3years); 2397 (45.0%) received an MRA (spironolactone or eplerenone). During follow-up, 204 (8.5%) patients treated with MRAs, developed AF, compared to 547 (18.6%) patients, without MRA treatment. Meta-analyses showed a significant overall reduction of AF risk in MRA treated patients (OR: 0.48 CI: 0.38-0.60 p<0.001), including a reduction of new-onset AF (OR: 0.52 CI: 0.37-0.74 p<0.001) and recurrent AF (OR: 0.37 CI: 0.24-0.57 p<0.001), but not post-operative AF (POAF) (OR: 0.60 CI: 0.33-1.09 p=0.09). CONCLUSIONS MRAs significantly reduce new-onset AF and recurrent AF, but not POAF. MRA treatment can be considered an additive therapeutic strategy in AF.

Electrophysiologically Guided Thoracoscopic Surgery for Advanced Atrial Fibrillation

Patients with symptomatic atrial fibrillation (AF) may require catheter or surgical ablation after antiarrhythmic drugs (AAD) have failed. Thoracoscopic surgical approaches aim to combine the reported efficacy of Cox-Maze procedures with less invasiveness, but long-term follow-up is unavailable. We

MicroRNAs in Atrial Fibrillation: from Expression Signatures to Functional Implications

Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with pronounced morbidity and mortality. Its prevalence, expected to further increase for the forthcoming years, and associated frequent hospitalizations turn AF into a major health problem. Structural and electrical atrial remodelling underlie the substrate for AF, but the exact mechanisms driving this remodelling remain incompletely understood. Recent studies have shown that microRNAs (miRNA), short non-coding RNAs that regulate gene expression, may be involved in the pathophysiology of AF. MiRNAs have been implicated in AF-induced ion channel remodelling and fibrosis. MiRNAs could therefore provide insight into AF pathophysiology or become novel targets for therapy with miRNA mimics or anti-miRNAs. Moreover, circulating miRNAs have been suggested as a new class of diagnostic and prognostic biomarkers of AF. However, the origin and function of miRNAs in tissue and plasma frequently remain unknown and studies investigating the role of miRNAs in AF vary in design and focus and even present contradicting results. Here, we provide a systematic review of the available clinical and functional studies investigating the tissue and plasma miRNAs in AF and will thereafter discuss the potential of miRNAs as biomarkers or novel therapeutic targets in AF.

The change in circulating galectin-3 predicts absence of atrial fibrillation after thoracoscopic surgical ablation

Aims Galectin-3 (Gal-3) is an important mediator of cardiac fibrosis, particularly in heart failure. Increased Gal-3 concentration (Gal-3), associated with increased risk of developing atrial fibrillation (AF), may reflect atrial fibrotic remodelling underlying AF progression. We aimed to investigate whether the change in serum Gal-3 reflects alterations of the arrhythmogenic atrial substrate following thoracoscopic AF surgery, and predicts absence of AF. Methods and results Consecutive patients undergoing thoracoscopic AF surgery were included. Left atrial appendages (LAAs) and serum were collected during surgery and serum again 6 months thereafter. Gal-3 was determined in tissue and serum. Interstitial collagen in the LAA was quantified using Picrosirius red staining. Ninety-eight patients (76% male, mean age 60 ± 9 years) underwent thoracoscopic surgery for advanced AF. Patients with increased Gal-3 after ablation compared to baseline had a higher recurrence rate compared to patients with decreased or unchanged Gal-3 (HR 2.91, P = 0.014). These patients more frequently had persistent AF, longer AF duration and thick atrial collagen strands (P = 0.049). At baseline, Gal-3 was similar between patients with and without AF recurrence: 14.8 ± 3.9 µg/L vs. 13.7 ± 3.7 µg/L, respectively in serum (P = 0.16); 94.5 ± 19.4 µg/L vs. 93.3 ± 30.8µg/L, respectively in atrial myocardium (P = 0.83). There was no correlation between serum Gal-3 and left atrial Gal-3 (P = 0.20), nor between serum Gal-3 and the percentage of fibrosis in LAA (P = 0.18). Conclusion The change of circulating Gal-3, rather than its baseline value, predicts AF recurrence after thoracoscopic ablation. Patients in whom Gal-3 increases after ablation have a high recurrence rate reflecting ongoing profibrotic signalling, irrespective of arrhythmia continuation.

Quality of life improves after thoracoscopic surgical ablation of advanced atrial fibrillation: Results of the Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery (AFACT) study

Objective: We evaluated health‐related quality of life at 12 months after thoracoscopic surgical ablation in patients enrolled in the Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery study. The Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery study assessed the efficacy and safety of ganglion plexus ablation in patients with symptomatic advanced atrial fibrillation undergoing thoracoscopic surgical ablation. Methods: Patients (n = 240) underwent thoracoscopic pulmonary vein isolation with additional ablation lines in patients with persistent atrial fibrillation. Subjects were randomized to additional ganglion plexus ablation or control. Short Form 36 quality of life questionnaires were collected at baseline and at 6 and 12 months of follow‐up. Results: A total of 201 patients were eligible for quality of life analysis (age 59 ± 8 years, 72% were men, 68% had an enlarged left atrium, 57% had persistent atrial fibrillation). Patients improved in physical and mental health at 6 months (both P < .01) and 12 months (both P < .01) relative to baseline, with no difference between the ganglion plexus (n = 101) and control (n = 100) groups. Short Form 36 subscores in patients with 1 or no atrial fibrillation recurrences were similar to those in the general Dutch population after 12 months. Patients with multiple atrial fibrillation recurrences (30%) improved in mental (P < .01), but not physical health, and 6 of 8 Short Form 36 subscales remained below those of the general Dutch population. Patients with irreversible, but not with reversible procedural complications had persistently diminished quality of life scores at 12 months. Conclusions: Thoracoscopic surgery for advanced atrial fibrillation results in improvement in quality of life, regardless of additional ganglion plexus ablation. Quality of life in patients with no or 1 atrial fibrillation recurrence increased to the level of the general Dutch population, whereas in patients with multiple atrial fibrillation recurrences quality of life remained lower. Irreversible but not reversible procedural complications were associated with persistently lower quality of life.