Researchers have presented a new method for assessing atrial remodelling in patients with atrial fibrillation (AF), based on the simultaneous assessment of electrical and contractile activity in the atria.
Details of the method have been set out in a paper published in Nature Communications.
Study leader David Filgueiras (Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain) explained that, until now, “this was an unmet challenge,” because, on the one hand, “the available technology did not allow the integration of both types of information to provide a more complete evaluation,” and on the other hand, “during atrial fibrillation, the contractile movements of the atria are of low intensity, and measuring them is technically challenging.”
Atrial fibrillation is currently classified according to the length of time that the patient has been in arrhythmia. Nevertheless, explained Filgueiras, “this temporal classification provides no information about a patient’s extent of atrial remodelling, an especially important parameter in the first months of the condition, when the underlying disease processes can progress at different rates.”
According to Filgueiras, the importance of this new diagnostic method is its ability to provide a personalised assessment of an individual patient’s degree of atrial remodelling, independently of the clinical classification based on temporal criteria”.
The three first authors on the study are Daniel Enríquez Vázquez (Complejo Hospitalario Universitario, A Coruña, Spain) and CNIC scientists Jorge G Quintanilla and Alba García Escolano.
Enríquez Vázquez highlighted that “on a clinical level, the results show that electromechanical dissociation in patients with AF is a solid indicator of disease progression and of the need to take urgent steps to return these patients to normal rhythm in an efficient and stable manner.”
Researchers integrated electrical and mechanical cardiac data to enable a personalised characterisation of the status of the pathological changes associated with the progression of AF.
In the first phase, engineers and physicists devised a strategy for integrating the electrical and mechanical data. The solution they found was to measure mechanical activity by Doppler imaging and electrical activity by surface electrocardiography.
The second phase involved experts in biology, biotechnology, biochemistry, and biomedical engineering working together with the CNIC Proteomics Unit and clinical cardiologists. Experimental studies conducted in this phase correlated the information obtained with the new approach with underlying pathological changes in atrial tissue. This information was used to develop new advanced mapping techniques and computer simulations to reveal the mechanisms underlying electrical and mechanical remodelling during the progression of AF.
The final phase was a multicentre prospective study of 83 patients at an early stage in the development of AF, to determine the prognostic value of simultaneous the electrical and mechanical assessment of the atria in patients with this type of arrhythmia.
The experimental and clinical findings revealed an imbalance between electrical and contractile activation in the atria at early stages of the disease. This causes the two parameters to become dissociated, so that the contractile activation cannot keep up with the electrical activation, a phenomenon the investigators call atrial electromechanical dissociation. The pace of this dissociation is specific to each individual patient, although in the absence of restoration of a normal rhythm it is usually observed within the first two to three months after an uninterrupted AF episode.
According to the researchers, a key advantage of the new approach is that atrial electromechanical dissociation is identified before the appearance of overt clinical signs of structural atrial remodelling.
“The use of this new diagnostic approach allows early characterisation of the underlying remodelling in patients with AF,” said Filgueiras. “The study shows that it is possible to integrate electrical and mechanical data from the atria of patients with AF to obtain personalised prognostic information about the clinical progression of the disease.”
