More thorough screening of patients with atrial fibrillation is needed before cryoballoon ablation treatment to prevent possible relapse
UZ Brussel cardiologist Dr. Andreea Motoc recently obtained her PhD at the VUB with a thesis on the role of the anatomy and function of the left atrium of the heart in predicting the outcome of cryoballoon ablation in patients with atrial fibrillation. This is the most common cardiac arrhythmia and manifests itself by such symptoms as palpitations, shortness of breath and fatigue. Cryoballoon ablation is currently the safest and most effective treatment. However, one third of patients continue to suffer from cardiac dysrhythmia after this intervention. With her PhD, Dr. Motoc tried to find out why this is the case and how the treatment can be optimised.
Atrial fibrillation is the most common heart rhythm disorder worldwide and is characterised by a rapid, irregular heart rhythm. Atrial fibrillation can lead to an increased risk of complications such as stroke or heart failure, reduced quality of life, cognitive dysfunction and death. An estimated 1 in 4 Belgians will experience at some point in their lives an atrial fibrillation.
The left atrium plays an important role in the initiation and continuation of atrial fibrillation.
Due to the chaotic, irregular heartbeats in the left atrium, this heart chamber undergoes a continuous adjustment process. The structure and function of the left atrium change and maintain the fibrillation: the function decreases and the size increases. This leads to a vicious circle.
There are several treatments available for atrial fibrillation, including cryoballoon ablation. This is currently one of the safest and most effective treatments available. As "cryo" (freezing) suggests, this technique uses a coolant to freeze the tissue at the entrance to the pulmonary veins in the left anterior chamber. This causes scarring, with the result that the electrical signals that cause atrial fibrillation are no longer transmitted.
Despite technological improvements, one third of patients still suffer from atrial fibrillation after ablation, leading to more hospital admissions, new interventions, complications and even death.
More detailed assessment of patients before intervention is needed
Dr Motoc's research shows that patients with atrial fibrillation should be assessed more systematically before undergoing cryoballoon ablation. This includes a complete assessment of the left atrium, looking at both structure and function. In this way, possible complications can be avoided and the number of new interventions reduced. This means a better quality of life for the patient and a lower impact on our healthcare system.
Dr. Andreea Motoc, cardiologist at UZ Brussel: "The aim of the research project was to evaluate the role of the left atrium anatomy and function in the recurrence of atrial fibrillation after cryoballoon ablation. Anatomical and functional parameters of the left atrium can be easily assessed in clinical practice using cardiac ultrasound (echocardiography), a procedure in which ultrasound is used to evaluate the structure and function of the heart.. "
Three-dimensional understanding of left atrial volume and size appears to be important predictor of relapse after cryoballoon ablation
The feasibility, reproducibility and accuracy of left atrium measurements by three-dimensional echocardiography were initially assessed in 244 patients. The study shows that for optimal assessment and follow-up of patients with various cardiac diseases such as atrial fibrillation, specific three-dimensional left atrium software packages should be used as they provide a more detailed and accurate insight.
Then, again using three-dimensional echocardiography, the role of the volume of the left atrium was analysed. To this end, the researchers followed up 172 patients for one year. Three-dimensional echocardiography clearly has added value in predicting the recurrence of atrial fibrillation after cryoballoon ablation, compared to the left atrium diameter or left atrium volume using two-dimensional echocardiography, which are classic parameters currently used in clinical practice to evaluate patients for intervention.
More advanced methods for evaluating left atrial function
Finally, so-called 'speckle tracking imaging' was used to evaluate left atrial function. This technique evaluates the deformation of the heart muscle by following the speckles that are formed naturally when the ultrasound interacts with the heart tissue. Left atrial function, assessed with speckle tracking echocardiography, also helps predict the recurrence of atrial fibrillation after ablation. A large number of the patients included in the study had impaired left atrial function but normal left atrial dimension. This finding suggests that more subtle forms of left atrial disease may be present even before left atrial enlargement in patients with atrial fibrillation.
Photo: Dr Motoc performs an echocardiography.
Karolien De Prez