Heart ailments are a common concern. You need to recognize the warning signs and take action to deal with them.
Elad Anter, a Professor of Medicine and Electrophysiologist from Cleveland Clinic, Ohio, shares new technologies in catheter ablation to treat atrial fibrillation (also referred as AFib) and other heart rhythm abnormalities like an atrial flutter, atrial tachycardia, and ventricular arrhythmias.
The Basics of Heart Rhythm Disorders
Before exploring new technologies, it is necessary to understand what heart rhythm disorders or arrhythmias are and how they affect the human body. The heart has an intrinsic or internal rhythm that is called sinus rhythm. Rhythm abnormalities involve the development of abnormal non-sinus rhythms, with atrial fibrillation being the most common serious rhythm abnormality particularly in older patients and those with medical comorbidities. It is experienced by about 5-10% of all individuals above 65 years of age. Other common rhythm abnormalities include atrial flutter, atrial tachycardia, atrioventricular reentrant tachycardia (or AVNRT), ventricular premature contractions (PVCs), or ventricular tachycardia. The latter, often occurs in patients with a known heart disease, such as patients who had experienced heart attack.
Symptoms vary depending on the specific rhythm abnormality and include palpitations, skipped beats, lightheadedness, shortness of breath, and even fainting. These are potential warning signs of a cardiac emergency. However, some patients are asymptomatic.
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Heart rhythm disorders are often diagnosed using careful history taking and tests like EKGs, Holter’s, and stress tests. Many times, imaging studies are also done such as echo or MRI.
Causes of Heart Rhythm Disorders
Arrhythmias are caused by disordered electrical signals in the heart. Faulty signaling may cause the heart to beat too rapidly (tachycardia), too slowly (bradycardia), or in an irregular rhythm, as in atrial fibrillation. These can happen in patients with normal or abnormal heart function (such as patients who has known scar in their heart because of a heart attack or other reasons). Some arrhythmias have benign, and the treatment is aimed at relieving symptoms while other arrhythmias can be dangerous and cause strokes or sudden death. The latter group requires careful evaluation and management by a heart rhythm specialist (electrophysiologist).
How Catheter Ablation Works
Elad Anter explains that ablation is a procedure that’s used to correct heart rhythm problems, particularly of patients with rapid or irregular rhythms. When the heart beats, the electrical signals that cause the heart to squeeze (contract) follow a specific pathway through the heart. During an arrhythmia, the normal electrical pulse site or path are disrupted. Depending on the type of heart rhythm problem, ablation may be one of the first treatments. Other times, it’s done when medicines don’t work or cause side effects.
Catheter ablation most often uses heating or cooling energies aimed to burn or freeze cells in the heart that are responsible for the arrhythmias. It creates tiny scars in the heart that usually don’t affect it function but just reduce the risk for. Arrhythmia recurrence. Ablation is often done using thin, flexible tubes called catheters that are inserted through the veins or arteries. Less commonly, ablation is performed during open or minimally invasive cardiac surgery.
New Technologies in Catheter Ablation
Pulsed-Field Ablation for Treatment of Atrial Fibrillation
Traditionally ablation is done using heating or cooling energies (radiofrequency of cryothermy, respectively) that destroy the cells by heating or colling them. While these are often effective, they are associated with some potential serious adverse effects such as esophageal injury and phrenic nerve paralysis explains Dr. Elad Anter. Recently, a new ablation technology using pulsed field energy (also called electroporation) has been introduced for treatment of arrhythmias. This energy can destroy cells without creating a significant thermal effect, thus, avoiding the serious risks associated with standard ablation energies. Dr. Anter’s research laboratory has been involved in some pioneering studies in this area particularly for treatment of atrial fibrillation and ventricular arrhythmias.
Non-Invasive Radiation Therapy for Ventricular Tachycardia
A second promising technology is the use of radiation to destroy cells causing arrhythmias. This is done using noninvasive techniques for delivery of precise ablative radiation with stereotactic body radiation therapy (SBRT). Dr. Anter commented that this work pioneered by Dr. Phillip Cuculich holds a promise for treatment of a wide range of arrhythmias.
Clinical Outcomes of Catheter Ablation
Elad Anter reports that clinical outcomes of arrhythmias are often dependent on the specific type of arrhythmia. Some arrhythmias, such as AVNRT, typical atrial flutter and a wide range of premature ventricular contractions (PVCs) can be cured with ablation while for other arrhythmias such as atrial fibrillation, ablation is useful in alleviating symptoms but not always curative. This is partially related to the limited scientific understanding of this and related arrhythmias.
Clinical Outcomes of Atrial Fibrillation using Pulsed Field Ablation
Early reports on the clinical use of pulsed field alation for the treatment of atrial fibrillation appear to be promising. In a recent study published at the Journal of the American college of Cardiology, investigators found that pulsed field ablation was able to achieve successful isolation of the pulmonary vein faster and safer compared to standard technologies. In another study published in Circulation Arrhythmia and Electrophysiology, Dr. Elad Anter and his colleagues showed that a new catheter, called a lattice-tip catheter was able to safely and rapidly ablate atrial fibrillation using either a combined radiofrequency and pulsed-field ablation approach capitalizing on the safety of PFA and the years of experience with radiofrequency energy.
Catheter Ablation Involving Radiation with stereotactic body radiation therapy Catheters
In a pivotal study published at the New England Journal of Medicine in 2017, a noninvasive treatment with electrophysiology-guided cardiac radioablation markedly reduced the burden of ventricular tachycardia. Newer studies also showed that Noninvasive treatment with SBRT is a feasible and effective approach for treatment of VT, particularly in sick patients who had failed previous ablation attempts. The utility of this method is still explored, however showed promise said Dr. Elad Anter.
