Mechanical atrial recovery after cardioversion in persistent atrial fibrillation evaluated by bidimensional speckle tracking echocardiography

Future Perspectives to Improve CHA2DS2VASc Score: The Role of Left Atrium Remodelling, Inflammation and Genetics in Anticoagulation of Atrial Fibrillation

In 10% of ischemic strokes, non-valvular atrial fibrillation (NVAF) is detected retroactively. Milder, or even asymptomatic forms of NVAF have shown high mortality, thrombotic risk, and deterioration of cognitive function. The current guidelines for the diagnosis and treatment of AF contain "grey areas", such as the one related to anticoagulant treatment in men with CHA2DS2-VASc score 1 and women with score 2. Moreover, parameters such as renal function, patient weight or left atrium remodelling are missing from the recommended guidelines scores. Vulnerable categories of patients including the elderly population, high hemorrhagic risk patients or patients with newly diagnosed paroxysmal episodes of atrial high rate at device interrogation are at risk of underestimation of the thrombotic risk. This review presents a systematic exposure of the most important gaps in evaluation of thrombotic and hemorrhagic risk in patients with NVAF. The authors propose new algorithms and risk factors that should be taken into consideration for an accurate thrombotic and hemorrhagic risk estimation, especially in vulnerable categories of patients.

Non-invasive electromechanical assessment during atrial fibrillation identifies underlying atrial myopathy alterations with early prognostic value

Electromechanical characterization during atrial fibrillation (AF) remains a significant gap in the understanding of AF-related atrial myopathy. This study reports mechanistic insights into the electromechanical remodeling process associated with AF progression and further demonstrates its prognostic value in the clinic. In pigs, sequential electromechanical assessment during AF progression shows a progressive decrease in mechanical activity and early dissociation from its electrical counterpart. Atrial tissue samples from animals with AF reveal an abnormal increase in cardiomyocytes death and alterations in calcium handling proteins. High-throughput quantitative proteomics and immunoblotting analyses at different stages of AF progression identify downregulation of contractile proteins and progressive increase in atrial fibrosis. Moreover, advanced optical mapping techniques, applied to whole heart preparations during AF, demonstrate that AF-related remodeling decreases the frequency threshold for dissociation between transmembrane voltage signals and intracellular calcium transients compared to healthy controls. Single cell simulations of human atrial cardiomyocytes also confirm the experimental results. In patients, non-invasive assessment of the atrial electromechanical relationship further demonstrate that atrial electromechanical dissociation is an early prognostic indicator for acute and long-term rhythm control.

Electrical cardioversion intervention in a patient with heat stroke accompanied by rapid atrial fibrillation: A case report and literature review

This report highlights the feasibility of electrical cardioversion intervention for the treatment of heat stroke complicated by rapid atrial fibrillation. There has never been any mentions in the previous literature of the possibility of electrical cardioversion in the event of heat stroke complicated by rapid arrhythmia. A 61-year-old man with classic heat stroke complicated by rapid atrial fibrillation was admitted to our emergency department. In the early stages of treatment, hemodynamics were not stable under the treatments of aggressive cooling and volume-expanding rehydration. It was considered to be related to rapid atrial fibrillation, and the administration of drug cardiover and control of ventricular rate failed. Subsequently, synchronous electrical cardioversion was given 3 times (biphasic wave, energy: 70J-80J-100J, respectively), successfully cardioversion and hemodynamically stable. Although the patient eventually died of progressive deterioration of multiple organ failure, timely cardioversion might be effective for the treatment of heat stroke complicated by rapid atrial fibrillation.

Imaging in atrial fibrillation: A way to assess atrial fibrosis and remodeling to assist decision-making

The 2020 ESC atrial fibrillation (AF) guidelines suggest the novel 4S-AF scheme for the characterization of AF. Imaging techniques could be helpful for this objective in everyday clinical practice, and information derived from these techniques reflects basic aspects of the pathophysiology of AF, which may facilitate treatment decision-making, and optimal management of AF patients. The aim of this review is to provide an overview of the mechanisms associated with atrial fibrosis and to describe imaging techniques that may help the management of AF patients in clinical practice. Transthoracic echocardiography is the most common procedure given its versatility, safety, and simplicity. Transesophageal echocardiography provides higher resolution exploration, and speckle tracking echocardiography can provide incremental functional and prognostic information over conventional echocardiographic parameters. In addition, LA deformation imaging, including LA strain and strain rate, are related to the extent of fibrosis. On the other hand, multidetector-row computed tomography and cardiac magnetic resonance provide higher resolution data and more accurate assessment of the dimensions, structure, and spatial relationships of the LA. Imaging is central when deciding on catheter ablation or cardioversion, and helps in selecting those patients who will really benefit from these procedures. Moreover, imaging enhances the understanding of the underlying mechanisms of atrial remodeling and might assists in refining the risk of stroke, which help to select the best medical therapies/interventions. In summary, evaluation of LA enlargement, LA remodeling and fibrosis with imaging techniques adds clinical and prognostic information and should be assessed as a part of routine comprehensive AF evaluation.

The Complex Relation between Atrial Cardiomyopathy and Thrombogenesis

Heart disease, as well as systemic metabolic alterations, can leave a ‘fingerprint’ of structural and functional changes in the atrial myocardium, leading to the onset of atrial cardiomyopathy. As demonstrated in various animal models, some of these changes, such as fibrosis, cardiomyocyte hypertrophy and fatty infiltration, can increase vulnerability to atrial fibrillation (AF), the most relevant manifestation of atrial cardiomyopathy in clinical practice. Atrial cardiomyopathy accompanying AF is associated with thromboembolic events, such as stroke. The interaction between AF and stroke appears to be far more complicated than initially believed. AF and stroke share many risk factors whose underlying pathological processes can reinforce the development and progression of both cardiovascular conditions. In this review, we summarize the main mechanisms by which atrial cardiomyopathy, preceding AF, supports thrombogenic events within the atrial cavity and myocardial interstitial space. Moreover, we report the pleiotropic effects of activated coagulation factors on atrial remodeling, which may aggravate atrial cardiomyopathy. Finally, we address the complex association between AF and stroke, which can be explained by a multidirectional causal relation between atrial cardiomyopathy and hypercoagulability.

Atrial fibrillation pattern and factors affecting the progression to permanent atrial fibrillation

Atrial fibrillation (AF) may progress from a non-permanent to a permanent form, and improvement in prediction may help in decision-making. In- and outpatients with non-permanent AF were enrolled in a prospective study and followed every 6 months. At baseline, 314 out of 523 patients (60%) had non-permanent AF (25.5% paroxysmal AF, 52.5% persistent, 2% first diagnosed AF). They were mostly males (188, 59.9%), median age 71 years [interquartile range (IQ) 62-77], median CHA₂DS₂VASc 3 (IQ 1-4), median HATCH score 1 (IQ 1-2). During a follow-up of 701 (IQ 437-902) days, 66 patients (21%) developed permanent AF. CHA₂DS₂VASc and HATCH scores were incrementally associated with AF progression (p for trend CHA₂DS₂VASc < 0.001, HATCH p = 0.001). Cox multivariable proportional hazard regression analysis showed that age [hazard ratio (HR) 1.042; 95%CI 1.005-1.080; p = 0.025], moderate-severe left atrial (LA) enlargement at echo (HR 2.072, 95%CI, 1.121-3.831; p = 0.020), antiarrhythmics drugs (HR 0.087, 95%CI 0.011-0.659, p = 0.018), EHRA score > 2 (HR 0.358, 95%CI 0.162-0.791, p = 0.011) and valvular disease (HR 2.196, 95%CI 1.072-4.499, p = 0.032) were significantly associated with AF progression. Adding "moderate-severe LA dilation" to clinical scores, eg. HATCH score (HATCH-LA) with 2 points (Cox multivariable regression analysis) improved prediction of AF progression vs. HATCH score (p = 0.0225). In patients without permanent AF, progression of AF was independently associated with age, LA dilation, AF symptoms severity, antiarrhythmic drugs and valvular disease. Adding LA dilation (moderate-severe volume increase) to clinical scores improved prediction of progression to permanent AF.