Joint AHA/ESC Session: Atrial Fibrillation: Comprehensive Management in 2009

This plenary session featured several distinguished speakers from across Europe and North America who reviewed the latest information in the area of atrial fibrillation.

Up first was Harry Crijns, MD, Professor and Chair, Department of Cardiology, University Hospital Masstricht, Masstricht, The Netherlands, who focused on the epidemiology of atrial fibrillation (AF). "AF is a disease of the elderly," he began, clarifying that the condition has a high prevalence in elderly patients and a prevalence that increases with age.

AF is "the most common highly prevalent sustained cardiac arrhythmia," he continued, adding that the prevalence is estimated at 2.3-5.1 million in US. "lifetime risk after age 40 is one in four, and the prevalence is expected to increase from 2 million to at least 5.6 million by 2050," with the Olmsted study predicting it be closer to 16 million.

But the increasing prevalence of AF isn't only because of an aging population. It is also the result of increasingly successful treatment of heart failure and myocardial infarction (reduced mortality), as well as increasing prevalence of such conditions as obesity, hypertension, and metabolic syndrome, stated Crijns.

He noted that the true prevalence of AF is unknown and is often only detected incidentally by pulse assessment and/or ECG screening; in a study of patients monitored closely after cardioversion, about 70% of all AF recurrences were asymptomatic. "I think this is the best plea for screening of high-risk populations," the speaker said.

Crijns then switched gears to focus on pathogenesis, noting that AF is not benign but linked to stroke, heart failure, bleeding due to OAC, and more. Also, "AF is a progressive disease. One year follow-up data of 4,192 patients with AF who were enrolled in the Euro Heart survey on AF shows that once have it, you almost certainly will have recurrences."

AF is closely related to background diseases, the presented stressed, adding that these include hypertension, coronary artery disease, heart failure, valve disease, asthma, diabetes, and hyperthyroidism and that they "need to be treated."

"If you have AF and come to the doctor for fist time, you can expect to have a lot of events in the next year," he continued. These adverse events, according to study results, include death from cardiovascular disease (2%), ischemic stroke (1.3%), CAD (6.6%), heart failure (9.5%), hospitalization for AF (18%), and hospitalization for cardiovascular reasons (30%).

"AFib runs in families based on gene mutations, polymorphisms, and environment," said Crijns. "Familial AF occurrence was noted in 1936 but only just recently gained more attention, because we're now much more able to look at these patients."

In the clinic, AF has two face pathophisiologically, explained Crijns. "AF can be an electrical disease (focal AF, lone AF, ablation successful), or AF can be the consequence of a preceding, longstanding vascular disease association with atrial enlargement and fibrosis."

"Once you see AF in a patient with underlying disease, be aware that much damage has already been done," continued the speaker." Managing arrhythmia is not enough. You have to manage the background diseases. "If it is so important to mange them, then why manage AF? AF is an independent predictor of MACCE, and new-onset AF is associated with increased morbidity and mortality in hypertensive patients."

Samuel Levy, MD, Professor of Medicine and Cardiology, University of Mediterranee, Marseille, France, continued the session with a discussion of drug therapy in AF, the goal of which he said is to restore and/or maintain sinus rhythm by preventing AF recurrences. After noting that available treatments include class I agents (sodium channel blockers) and class III agents (potassium channel blockers), Levy focused on the new antiarrythmic agents, particularly dronedarone.

Levy reviewed data from a trial for which 4626 patients were randomized to dronedarone or placebo with first hospitalization due to cardiovascular disease or death as the primary endpoint. Results show that the endpoint was reached, as was the secondary endpoint of hospitalization due to cardiovascular events.

"Dronedarone is a safe drug," the speaker stated, with two studies showing significant reduction in first AF recurrence in those who received the agent, as well as reductions in days in hospital, AF-related hospitalization, and CV-related hospitalization. The ATHENA trial also shows less stroke with dronedarone use, he noted. Levy concluded that dronedarone represents and interesting option with a good safety profile and is the first agent to show a decrease in CV mortality and reduced AF-related hospitalizations.

Up next was Joseph Brugada, MD, PHD, Associate Professor of Medicine and Director, Arrhythmia Unit Cardiovascular Institute, Hospital Clinic, University of Barcelona, Spain, who explained that "many patients with AF have controlled arrhythmia and appear asymptomatic." He warned attendees to "be careful in selecting what patients can benefit from ablation." Other key points he made upfront were that AF is a trigger for heart failure in many patients and that a more devastating effect of AF is the presence of stroke, "which can be very disabling."

The current guidelines for AF include simplified, general information, explained Brugada, which read "Catheter ablation is a reasonable alternative to pharmacological therapy to prevent recurrent AF in symptomatic patients with little or no LA enlargement." And the clinical evidence backing these guidelines is limited.

Brugada focused the majority of the rest of his presentation on statements from the HRS/EHRA/ECAS Task Force, which says that the consensus is that the "primary indication for catheter AF ablation is the presence of symptomatic AF refractory or intolerant to at least one class I or III agent." The Task Force also says that "In rare clinical situations, it may be appropriate to perform catheter ablation of AF as first line therapy," "Catheter ablation of AF is also appropriate in selected symptomatic patients with heart failure and/or reduced ejection fraction," and "The presence of a LA thrombus is a contraindication to catheter ablation of AF."

"It is important to recognize that catheter relation of AF is a demanding technical procedure that may result in complications," added Brugada. "Keep in mind every single time that you can harm the patient with this procedure. Weigh the benefits versus the risks. Complications include pericarditis, transient ST segment elevation, transient ischemic cerebral damage, dysphagia, vascular complications, and tamponade. Make sure to minimize them." Backing this up, Brugada quoted recommendations from the Task Force, which said "patients should only undergo AF ablation after carefully weighing the risks and benefits of the procedure."

The primary clinical benefit of catheter ablation for AF is an improvement in quality of life resulting from elimination of arrhythmia-related symptoms, such as paliotations, fatigue, or effort intolerance, according to the Task Force. Thus, he said, the primary selection criterion of catheter ablation should be the presence of symptoms. Other considerations in patient selection include age, LA diameter, and duration of AF.

The Task Force also says "Heighted risk of myocardial performance and thromboembolic complications in very elderly patients, and the lower probability of successful outcomes when LA is markedly dilated, or patients with longstanding persistent AF should be taken into account when considering ablation."

Continuing, Brugada stated that many patients with AF may be asymptomatic "but seek catheter ablation as an alternative to long-term anticoagulation with Wafarin; patients desire to eliminate the need for long-term anticoagulation." However, the Task Force states, "Discontinuation of Warfarin therapy post ablation is generally not recommend in patients with CHF, a history of high blood pressure, age of 74 years or older, diabetes, prior stroke, or transient ischemic attack."

Brugada summarized his key points, stating that "it is well recognized that symptomatic and/or asymptomatic AF may recur during long-term follow-up after an AF ablation procedure, that RF ablation of AF is not a first line therapy yet, and that some exceptions do exist." He closed, advising attendees to "weigh the risks and benefits and consider symptoms as the main indication and recognize hypertension as a predictor of AF ablation success."

Denis Roy, MD, University of Montreal, Montreal, Canada, continued the session, quickly running through his key points, which were as follows:

• Management of AF with the rhythm control strategy offers no survival advantage over the rate control strategy.
• The expected superiority of rhythm control has not been demonstrated.
• Sinus rhythm is either an important determinant of survival or a marker for factors associated with survival.
• The good effect or restoring SR may be offset by the bad effect of fatal toxicity.
• Traditional risk factors correlate with mortality in patients with AF and CHF
• Warfarin therapy is associated with improved survival
• SR versus AF is not a predictor of outcome, which is also true for AAD use, according to the AF-CHF trials.
• The ATHENA trial shows that first hospitalization for any reason, or specifically for AF, CHF, ACS, or syncope, is lower with dronedarone than with placebo.
• The comprehensive management of AF should address its multiple impacts