Atrial fibrillation or AFib is a common heart rhythm abnormality that affects millions of Americans. It causes heart rhythm irregularity that may be felt as palpitations or skipped beats and is sometimes a cause for fatigue or shortness of breath. The main threat of Afib is the associated increased risk for a stroke.
Fortunately, several treatment methods can help people with atrial fibrillation have better and healthier lives.
Elad Anter, a Professor of Medicine from Cleveland, Ohio, explains how catheter ablation is used to treat AFib and how new surgical techniques are helping more people survive the effects of the condition.
What is Atrial Fibrillation?
Atrial fibrillation is a common heart rhythm disorder (also called arrhythmia). The heart beats irregularly, and sometimes too fast.
Some patients do not have symptoms; however, the majority do have some symptoms ranging from rhythm irregularity, palpitations, fatigue, shortness of breath, or subtle changes such as difficulty to focus and perform.
When the heart is in atrial fibrillation, the upper chambers, called atria, do not contract regularly. This leads to stasis of blood with increased risk for blood clot formation. If the blood clot leaves the heart it can travel to the brian and cause a stroke.
What are the Symptoms of Atrial Fibrillation?
People with atrial fibrillation may or may not have symptoms. Symptoms include an irregular heartbeat or palpitation, reduced energy level, challenges to focus and perform, rapid heart rate, or lightheadedness. Some may experience chest pain and shortness of breath.
What are the Risk Factors?
AFib often but not always develops in patients with risk factors. Common risk factors include aging (risk increase after ~50-years of age), hypertension, diabetes, coronary artery disease, obstructive sleep apnea, and obesity.
AFib’s Relation to Stroke
AFib may cause a stroke. This is largely because the upper chambers of the heart do not squeeze in a regular fashion, which leads to slow blood flow in certain pockets within the atria. This slow blood flow promotes clot formation. When the clot leaves the heart, it may travel to the brain and cause a stroke. hard time to focus. This is called an ischemic stroke – a clot that blocks blood flow to the brain. However, in patients with AFib taking blood thinners to reduce the risk of clot formation, stroke can also occur because of the increased risk of bleeding in the brain as a result of mild head trauma.
Treatments for Atrial Fibrillation
There are several treatment avenues that physicians like Elad Anter may choose from, depending on the specific symptoms and risk factors in each patient. The first line of defense is often prescription medicines like metoprolol, propranolol, and diltiazem to slow a rapid heart rate. Patients may also be given blood thinners to reduce the risk of stroke.
Patients are encouraged to change their lifestyles and pay more attention to their general health, cutting back on alcohol consumption and quitting smoking, and controlling their other comorbid disorders like hypertension, diabetes, sleep apnea and obesity.
Catheter ablation is one of the most effective techniques used in the treatment of atrial fibrillation. This technique involves heart catheterization in which the electrophysiologist (cardiologist specializing in rhythm abnormalities) inserts a catheter (flexible wire or tube) into the heart and target with heating or cooling energy electrical triggers causing atrial fibrillation. These often reside in the left atrium at locations where the pulmonary veins drain into the atria. The heating or cooling energy creates a small scar around the pulmonary veins that results in electrical isolation of these pulmonary veins. The procedure is often called pulmonary vein isolation of PVI.
The technology of catheter ablation has evolved significantly over the past two decades and it is now considered a first line therapy for most patients with AFib because it is effective and safe compared to medications. Dr. Elad Anter’s laboratory has been involved in development of many new technologies for catheter ablation of AFib.
Typical Strategies for Catheter Ablation of AFib
Elad Anter explains some of the catheter ablation techniques for atrial fibrillation:
- Pulmonary Vein Isolation: Because the most common triggers of atrial fibrillation originate in the connections of the 3-5 pulmonary veins with the left atrium, the cornerstone of atrial fibrillation ablation in to eliminate these triggers. This is done by creating a line of electrical isolation at the junction between the left aria and the pulmonary vein for achieving pulmonary vein isolation (PVI). This line of electrical isolation is created with technologies that can destroy cells selectively, precisely, and safely. The most common energy sources used by catheters are radiofrequency (causing cellular death by heating the cells) or cryothermy (causing cellular death by cooling the cells). These have relatively equivalent success rate and safety profile. A new energy source called pulsed field ablation (PFA) is likely superior to existing energies (radiofrequency and cryothermy) as it can achieve PVI more rapidly and with much lower risk for major complications. Leading physicians like Elad Anter are gaining considerable experience with these new technologies.
- Ablation beyond Pulmonary Vein Isolation (PVI): Treatment of AFib is more effective at early disease stages, where the arrhythmia occurs intermittently but not constantly. While PVI alone is often sufficient in early disease stages, it may be insufficient in patients at more advanced disease. These patients may have additional triggers for atrial fibrillation and require more extensive ablation in the left and sometimes right atria.
- AV Node Ablation: AV node ablation is occasionally used to treat patients with atrial fibrillation who have rapid heart rates despite treatments with medications and catheter ablations. The AV node is the structure in the heart that conducts the electrical impulses from the upper to the lower chambers. If this is removed, the fast rate in the upper chambers will not be transmitted to the lower chambers and the overall heart rate will be stable and dependent on a pacemaker.
- AFib is a common heart rhythm abnormality that often develops in patients with risk factors such as obesity, hypertension, diabetes, and sleep apnea.
- The most common symptoms of AFib are palpitations, fatigue, and anxiety. However, the most dreadful threat is the increased risk of stroke. These patients often take blood thinners to reduce the risk for stroke.
- Catheter ablation of AFib is an effective procedure in patients with symptoms related to AFib. It offers a better efficacy and safety profile compared to medications.