By Efrat Ohayon, Science and Technology Editor
Atrial fibrillation is the most common cardiac arrhythmia and is associated with an increased risk of stroke. Cardiac arrhythmia, defined by the irregular beating of the heart, leads to an elevated risk of stroke. This risk stems from the impact of fibrillation in the heart.
Atrial fibrillation affects the atria of the heart, specifically the upper chambers. In comparison to the normal rhythm of the heart, sinus rhythm, when the heart beats in a normal pattern, fibrillation means that the heart misfires electrical signals, leading to irregular heart patterns. These irregularities lead to a buildup of blood in the atrial chambers, as not all of the blood is squeezed out. This retained blood poses a risk as it can clot and cause a stroke if the blood clot reaches the brain.
The Cox-Maze IV procedure has been utilized to restore sinus rhythm in patients. This procedure is a surgical ablation technique that creates scar tissue using heat, cold, or high-energy pulses to interrupt abnormal electrical signals to restore sinus rhythm. Current guidelines for post-operative care following this procedure vary as the Heart Rhythm Society guidelines do not provide specific recommendations for oral anticoagulant use following surgical ablation (SA). The purpose of oral anticoagulation is to reduce the risk of stroke by thinning the blood with a purpose of eliminating blood clots. The Heart Rhythm Society, European Heart Rhythm Association and the European Cardiac Arrhythmia Society have all recommended lifetime use of warfarin anticoagulation in patients with a CHADS2 score (Congestive heart failure, hypertension, age, diabetes and stroke) of at least 2 following ablation for atrial fibrillation.
In addition to the Maze procedure, there is newer research suggesting that catheter-based ablation might be beneficial. Catheter-based ablation is minimally invasive and has been used to treat atrial fibrillation and supraventricular tachycardia. This procedure consists of inserting a flexible tube through blood vessels to reach the heart. Once in the proximity of the area that requires ablation, heat or extreme cold is directed to the targeted area. Contrary to the Maze procedure, where a pattern of scar tissue is created to direct electrical signals in the heart, catheter-based ablation creates an area of scar tissue that blocks the irregular electrical signals.
A newer form of catheter-based ablation, called pulsed field ablation, has been developed to treat cardiac arrhythmias. This method uses rapid electrical pulses that create interruptions to the membranes of the heart cells, causing the treated cells to die and form scar tissue. This method does not require the use of extreme heat or cold temperatures, which protects the surrounding structures such as the pulmonary veins. Patients who have undergone pulsed field ablation have lower rates of returning atrial fibrillation than other methods.
Together, these methods demonstrate the constant effort by physicians and scientists to develop methods to treat the same problem. Surgeons continue to refine the Maze procedure and catheter-based ablation as well as pulsed field ablation to develop the best technique to eliminate cardiac arrhythmias and reduce risks of stroke.
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