Mechanistic Pathways Underlying Genetic Predisposition to Atrial Fibrillation Are Associated With Different Cardiac Phenotypes and Cardioembolic Stroke Risk.

Background: Genome-wide association studies have clustered candidate genes associated with atrial fibrillation (AF) into biological pathways reflecting different pathophysiological mechanisms. We investigated whether these pathways associate with distinct intermediate phenotypes and confer differing risks of cardioembolic stroke.

Methods: Three distinct subsets of AF-associated genetic variants, each representing a different mechanistic pathway, that is, the cardiac muscle function and integrity pathway (15 variants), the cardiac developmental pathway (25 variants), and the cardiac ion channels pathway (12 variants), were identified from previous AF genome-wide association studies.

In Silico TRials guide optimal stratification of ATrIal FIbrillation patients to Catheter Ablation and pharmacological medicaTION: the i-STRATIFICATION study.

Aims: Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials.

Methods And Results: A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram.

Changes in the investigation and management of suspected myocardial infarction and injury during COVID-19: a multi-centre study using routinely collected healthcare data.

Objective: The COVID-19 pandemic was associated with a reduction in the incidence of myocardial infarction (MI) diagnosis, in part because patients were less likely to present to hospital. Whether changes in clinical decision making with respect to the investigation and management of patients with suspected MI also contributed to this phenomenon is unknown.

Methods: Multicentre retrospective cohort study in three UK centres contributing data to the National Institute for Health Research Health Informatics Collaborative.

What determines the optimal pharmacological treatment of atrial fibrillation? Insights from in silico trials in 800 virtual atria.

The best pharmacological treatment for each atrial fibrillation (AF) patient is unclear. We aim to exploit AF simulations in 800 virtual atria to identify key patient characteristics that guide the optimal selection of anti-arrhythmic drugs. The virtual cohort considered variability in electrophysiology and low voltage areas (LVA) and was developed and validated against experimental and clinical data from ionic currents to ECG.

Reduced Left Atrial Rotational Flow Is Independently Associated With Embolic Brain Infarcts.

Background: Up to 25% of embolic strokes occur in individuals without atrial fibrillation (AF) or other identifiable mechanisms.

Objectives: This study aims to assess whether left atrial (LA) blood flow characteristics are associated with embolic brain infarcts, independently of AF.

Methods: The authors recruited 134 patients: 44 with a history of ischemic stroke and 90 with no history of stroke but CHADSVASc score ≥1.

Efficacy and safety of same-day discharge after atrial fibrillation ablation compared with post-procedural overnight stay: a systematic review and meta-analysis.

Aims: Catheter ablation for atrial fibrillation (AF) has historically required inpatient admission post-procedure, but same-day discharge (SDD) has recently been reported. We aimed to assess the efficacy and safety of SDD compared with overnight stay (OS) post-ablation.

Methods And Results: We performed a systematic search of the PubMed database.

The impact of atrial fibrillation and stroke risk factors on left atrial blood flow characteristics.

Aims: Altered left atrial (LA) blood flow characteristics account for an increase in cardioembolic stroke risk in atrial fibrillation (AF). Here, we aimed to assess whether exposure to stroke risk factors is sufficient to alter LA blood flow even in the presence of sinus rhythm (SR).

Methods And Results: We investigated 95 individuals: 37 patients with persistent AF, who were studied before and after cardioversion [Group 1; median CHA2DS2-VASc = 2.

Left atrial 4D flow cardiovascular magnetic resonance: a reproducibility study in sinus rhythm and atrial fibrillation.

Background: Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) allows sophisticated quantification of left atrial (LA) blood flow, and could yield novel biomarkers of propensity for intra-cardiac thrombus formation and embolic stroke. As reproducibility is critically important to diagnostic performance, we systematically investigated technical and temporal variation of LA 4D flow in atrial fibrillation (AF) and sinus rhythm (SR).

Methods: Eighty-six subjects (SR, n = 64; AF, n = 22) with wide-ranging stroke risk (CHADSVASc 0-6) underwent LA 4D flow assessment of peak and mean velocity, vorticity, vortex volume, and stasis.

Mechanisms of atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained arrhythmia, currently affecting over 33 million individuals worldwide, and its prevalence is expected to more than double over the next 40 years. AF is associated with a twofold increase in premature mortality, and important major adverse cardiovascular events such as heart failure, severe stroke and myocardial infarction. Significant effort has been made over a number of years to define the underlying cellular, molecular and electrophysiological changes that predispose to the induction and maintenance of AF in patients.

Myocardial Perfusion Is Impaired and Relates to Cardiac Dysfunction in Patients With Atrial Fibrillation Both Before and After Successful Catheter Ablation.

Background Atrial fibrillation ( AF ) is associated with myocardial infarction, and patients with AF and no obstructive coronary artery disease can present with symptoms and evidence of cardiac ischemia. We hypothesized that microvascular coronary dysfunction underlies these observations. Methods and Results Myocardial blood flow ( MBF ) at baseline and during adenosine stress and left ventricular and left atrial function were evaluated by magnetic resonance in 49 patients with AF (25 paroxysmal, 24 persistent) with no history of epicardial coronary artery disease or diabetes mellitus, before and 6 to 9 months after ablation.

Diagnosis of Microvascular Angina Using Cardiac Magnetic Resonance.

Background: In patients with angina and nonobstructive coronary artery disease (NOCAD), confirming symptoms due to coronary microvascular dysfunction (CMD) remains challenging. Cardiac magnetic resonance (CMR) assesses myocardial perfusion with high spatial resolution and is widely used for diagnosing obstructive coronary artery disease (CAD).

Objectives: The goal of this study was to validate CMR for diagnosing microvascular angina in patients with NOCAD, compared with patients with obstructive CAD and correlated to the index of microcirculatory resistance (IMR) during invasive coronary angiography.

Gadolinium-Free Cardiac MR Stress T1-Mapping to Distinguish Epicardial From Microvascular Coronary Disease.

Background: Novel cardiac magnetic resonance (CMR) stress T1 mapping can detect ischemia and myocardial blood volume changes without contrast agents and may be a more comprehensive ischemia biomarker than myocardial blood flow.

Objectives: This study describes the performance of the first prospective validation of stress T1 mapping against invasive coronary measurements for detecting obstructive epicardial coronary artery disease (CAD), defined by fractional flow reserve (FFR <0.8), and coronary microvascular dysfunction, defined by FFR ≥0.

Correction to: Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease.

In the original publication of this article [1] Fig. 1 was incorrect due to the use of a colour bar with wrong range in error.

Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease.

Background: Type 2 diabetes mellitus (T2DM) is associated with coronary microvascular dysfunction in the absence of obstructive coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) T1-mapping at rest and during adenosine stress can assess coronary vascular reactivity. We hypothesised that the non-contrast T1 response to vasodilator stress will be altered in patients with T2DM without CAD compared to controls due to coronary microvascular dysfunction.