New Ways to Tame an Abnormal Heartbeat
If you’re one of the roughly 2.7 million Americans who has atrial fibrillation (AFib), the most common form of abnormal heart rhythm, you may be due for an in-depth discussion with your doctor about your treatment. You could stand to benefit from new, game-changing drugs and strategies for managing the condition that have emerged during the past few years.
AFib produces a rapid, irregular heartbeat (arrhythmia). Symptoms include fatigue, chest discomfort or pain, shortness of breath, and reduced blood flow to the brain that can lead to fainting or confusion. But many people with AFib have no symptoms. With or without them, the condition significantly increases the risk for blood clots that can cause stroke, heart failure, and other serious health threats. In fact, people who have AFib have five times the chance of a having a stroke as those who don’t have the disorder.
The main changes
Updated clinical guidelines reflect new, approved options for managing AFib and urge doctors and patients to revisit their current treatment with these drugs and strategies in mind. The guidelines were jointly issued in 2014 by the American Heart Association, the American College of Cardiology, and the Heart Rhythm Society in collaboration with the Society of Thoracic Surgeons, and published by the Journal of the American College of Cardiology.
While not everyone may be a candidate for a fully revised treatment strategy, the guidelines will likely affect many AFib patients in one way or another. They address four major changes of concern to patients—namely, a more effective way to assess stroke risk; alternatives to a blood thinner that are safer and easier to use; a diminished role for daily aspirin therapy; and broader use of radiofrequency ablation, a minimally invasive procedure to restore normal heart rhythm.
1. Revaluate stroke risk
The treatment plan your doctor prescribes depends partly on your overall stroke risk. Simply having AFib raises your odds, but your vulnerability to a stroke increases with the presence of other risk factors. In the past, most doctors estimated a patient’s stroke risk using a tool called CHADS2, which calculates a risk score by assigning one point for each risk factor a patient has, with the exception of past stroke, which scores two points.
The acronym CHADS2 refers to those risk factors, which are:
• Congestive heart failure, or the heart’s inability to pump blood adequately
• Hypertension, or high blood pressure (above 140/90 mm Hg)
• Age (75 or older)
• Stroke (past history of strokes or transient ischemic attacks, or “ministrokes”)
However, CHADS2 has some shortcomings. It does a relatively poor job of identifying patients who have a very low risk for stroke and fails to account for a number of important risk factors. That led to a refined scoring system, CHA2DS2- VASc. The more comprehensive calculator refines the age score by adding an extra point for being 75 or older and includes three more factors that increase stroke risk:
• Vascular disease (such as peripheral artery disease, heart attack, aortic plaque)
• Age (65 to 74)
• Sex category (female gender)
Scores can range from 0 (low risk) to 9 (a 15 percent increased risk of stroke per year). The score upgrade could have important implications for deciding whether you should begin anticoagulant therapy.
2. Consider newer blood thinners
If you have AFib, your doctor may have prescribed the drug warfarin (Coumadin), an anticoagulant. Anticoagulants prevent the formation of dangerous blood clots that can cause strokes. Until recently warfarin was the sole anticlotting drug for AFib patients at risk of stroke. Although warfarin is effective for preventing strokes, it’s challenging to manage. Patients must be regularly monitored with blood tests and avoid eating foods high in vitamin K, which can affect how the drug works.
Since the guidelines for treating AFib were last updated in 2006, four new oral anticoagulants have entered the market: dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa). Studies show that these drugs are as effective as warfarin, and in some cases superior.
These alternative anticoagulants offer some advantages—notably, an easier regimen to follow. There’s no need for frequent monitoring or dose adjustments. Foods don’t affect how the drugs are metabolized, so it’s OK to eat foods that contain vitamin K. And all three drugs are less likely to cause serious, life-threatening bleeding, especially in and around the brain. Once started, these medications should never be discontinued without talking to your doctor.
Cost should be considered, too—the newer drugs are significantly more expensive than warfarin, although you’ll no longer have to pay for routine monitoring.
If you have a mechanical heart valve, warfarin is your only option; the new drugs aren’t approved for patients with heart valve problems. Patients with severe kidney disease also aren’t candidates.
Earlier guidelines recommended aspirin for AFib patients who otherwise have no major risk factors for a stroke, such as high blood pressure or diabetes, or who can’t take warfarin or other anticoagulant drugs. The 2014 update questions that practice. The authors found little evidence that aspirin alone prevents strokes in patients with AFib.
4. Consider earlier ablation therapy
The new guidelines suggest that doctors expand their use of a procedure known as radiofrequency catheter ablation to restore normal heart rhythm in symptomatic patients with nonvalvular AFib (AFib with no history of a prosthetic heart valve, mitral valve repair, or rheumatic mitral stenosis).
In this procedure, doctors snake small wires called catheters through an entry point in the groin and into the heart’s chambers. The catheters deliver low-wattage pulses of electricity to destroy the cells causing erratic heartbeats. In some cases, an artificial pacemaker is implanted to help maintain heart rhythm.
The 2014 guidelines encourage doctors to offer radiofrequency ablation early on as an alternative to drugs to selected patients who have intermittent, or paroxysmal, AFib (AFib that stops on its own or with intervention after no more than seven days) or persistent AFib (continuous AFib for more than seven days). Ablation shouldn’t be used on people who can’t be treated with anticoagulants; most patients who undergo the procedure must continue to take them.
Radiofrequency ablation hasn’t been well studied in older patients and patients with long-standing, persistent AFib (AFib that lasts longer than a year), and there’s no evidence that the procedure prevents strokes, heart failure, or death. Radiofrequency ablation also carries some risks. Complications are rare but include risk of blood clots, injury to the heart and blood vessels, infection, bleeding, and new arrhythmias.
More than one-third of people with AFib are ages 80 and older. If you belong to this age group, keep in mind that elderly people with AFib often have mild or no symptoms—a good reason to be sure your doctor screens you regularly.
The new guidelines remind doctors that older men and women diagnosed with AFib often have one or more other medical conditions, such as hypertension or heart disease. This may influence treatment. Also, side effects from anti-arrhythmic drugs can be intensified in the elderly.
Often, a preferred strategy for an older patient with few symptoms is rate control—slowing a rapid heart rate with drugs that include beta-blockers, calcium-channel blockers or (less frequently because it carries risks) digoxin.