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The cardiovascular complications of atrial fibrillation can occur suddenly and may result in permanent harm. An abnormal heartbeat may lead to a pooling of blood in the atria, which can increase the risk of stroke. The primary aim of treatment is usually the prevention of thromboembolism, together with control of ventricular rate response and restoration and maintenance of sinus rhythm when feasible.
Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting 1–2% of Europeans. Its prevalence increases with age, and its presentation varies in terms of symptoms and severity. “One estimate suggests that there are about 8 million Europeans with AF at present but that this will rise to about 18 million by 2060,” European Heart Rhythm Association President Professor John Camm (St. George’s University, London, UK) told ESC Congress News: “The population is ageing, and it is ageing with a back - ground of cardiovascular disease that might previously have proven fatal but that now has become a chronic condition that needs to be managed.”
Estimating an accurate prevalence of AF is confounded by its sometimes asymptomatic presentation. So-called “silent atrial fibrillation” may occur intermittently and without symptoms. “Calculations based on clinical presentation with the arrhythmia or cross-sectional surveys may seriously underestimate the prevalence of the disease, and it is generally assumed that about 25% to 33% of AF remains unrecognised,” Prof. Camm explains. “This unrecognised arrhythmia may then lead to cardiovascular complications such as stroke, dementia, heart failure and death, sometimes sudden death.”
AF can occur paroxysmally, persistently or permanently. In paroxysmal cases, abnormal electrical signals and heart rate begin suddenly and end without intervention. These symptoms can vary in severity, and may last from a few seconds to several days. Persistent AF involves an abnormal heart rhythm which continues until it is stopped by treatment. In cases of permanent AF, symptoms remain in spite of usual treatment methods. Over time, paroxysmal and persistent AF can both become permanent.
Therapy for AF often involves the use of anticoagulants, which offer an effective and relatively inexpensive method of stroke prevention. In asymptomatic patients, however, there are concerns that stroke may not be such an extensive burden, Prof. Camm says. In these instances, treatment by anticoagulation may not always be so cost-effective. This needs further investigation.
The introduction of novel oral anticoagulants (NOACs) has brought a number of benefits for patients. “NOAC therapy is more convenient for patients, because it involves no dietary restrictions, fewer drug-drug interactions and no regular testing of anticoagulation status. Importantly, is associated with less life-threatening and intracranial bleeding,” Prof. Camm told ESC Congress News. AF can also be treated by vitamin K antagonists (VKA), but the net clinical benefit of NOAC therapy is higher. “Although NOAC drugs are more expensive than VKA treatment, the overall strategy of NOAC treatment for stroke prevention in AF is cost-effective in most western countries,” Prof. Camm explains, “therefore, NOAC treatment is regarded as preferable to VKA treatment for stroke prevention in patients with AF and risk factors for stroke.” In patients for whom anticoagulation therapy is not suitable, treatment by left atrial appendage (LAA) closure may be appropriate to reduce the risk of stroke. “In skilled hands, it is easy and safe to deploy a device, and follow-up is simple and straightforward,” Prof Camm says.
In addition to stroke prevention, a number of therapies exist for the treatment of symptoms associated with AF. For paroxysmal AF patients who present with little underlying heart disease and in whom structural atrial changes have not occurred, catheter ablation may offer an effective treatment for their symptoms. It is usually performed for pulmonary vein isolation from the left atrium, using radiofrequency or cryotherapy. AF is not always easy to treat.
“A fundamental problem that we have with ablation treatment for AF is that we do not know much about the mechanism that sustains AF,” Prof. Camm told ESC Congress News. “This implies that treatments that are provided for persistent and permanent AF may not be directed at the right target.” Cryoablation is now an established therapy for symptomatic atrial fibrillation, but the merits of therapies delivered by balloon technology, such as radiofrequency, laser, or hot balloon, are still being evaluated. While the ability of ablation to treat more than the symptoms of AF is unknown, studies are underway to evaluate its potential for reducing mortality, heart failure and stroke. Prof. Camm argues that interest in AF should extend far beyond electrophysiologists. “AF is so highly prevalent that physicians and surgeons of every variety will encounter patients with this condition. Since most of these patients will be taking, or ought to be taking anticoagulants, they must be monitored very carefully to ensure that their treatment remains safe and effective, and that it does not interfere with other therapies the patient may need,” he states.
Resources of the session: Atrial fibrillation
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