For Mellanie True Hills, an arrhythmia — or abnormal heart rhythm — feels like “a fish flopping around in your chest.” It first happened in 2003. She was checking E-mail in her home office, just a few hours after getting off a plane and seven months after having a heart attack.
The 51-year-old from Decatur, TX, got emergency care when other symptoms — dizziness, lightheadedness, a racing heart, blurriness in her right eye, and a right leg that was “white and cold as snow” alarmed her. At the hospital, True Hills learned that blood clots were forming in her heart and that she had nearly had a stroke. She was diagnosed with atrial fibrillation, the most common arrhythmia, affecting 2.2 million Americans.
“Heart rhythm problems are essentially an experience of being human,” says Todd Cohen, M.D., Director of Electrophysiology and the Pacemaker/Arrhythmia Center at Winthrop-University Hospital. “Many [heart rhythm abnormalities] are benign, but unfortunately some of them are serious, life-disrupting, and malignant,” he adds.
More than 780,000 people are hospitalized because of a heart rhythm disturbance each year in the U.S., says Cohen, who wrote A Patient's Guide to Heart Rhythm Problems (Johns Hopkins University Press, 2010).
THE NORMAL HEART RHYTHM
To understand abnormal heart rhythms, you first need to know how the heart normally works. The heart is divided into four chambers. On top are the right atrium and left atrium (or, “the atria”) that receive blood back from the body and lungs. On the bottom are the right and left ventricles, the main pumping chambers of the heart.
The right atrium collects blood that has been throughout the body and is depleted of oxygen. This spent blood passes to the right ventricle so it can be pumped into the lungs and stock up with oxygen. The left atrium collects oxygenated blood from the lungs, which then passes to the left ventricle so it can be pumped into the aorta — the body's main artery — and then fed to smaller arteries throughout the body. The right and left side of the heart work together simultaneously, so the blood can circulate efficiently throughout the body.
But what controls the coordinated contraction of the heart to deliver blood efficiently? The answer will electrify you: Nestled in the upper wall of the right atrium is a collection of cells that form the sinoatrial (SA) node — the heart's natural pacemaker. The SA node sends electrical impulses into the heart muscle, causing it to contract. The atria contract first, causing blood to flow into the ventricles. Then, the ventricles contract, pumping blood either to the lungs to pick up oxygen or to the rest of the body to provide oxygen and nutrients for working tissues like those of the brain, muscle, and kidney.
ABNORMAL HEART RHYTHMS
Normally, these electrical impulses occur in a steady, regular rhythm. The cells within the SA node have special properties that cause them to set off the electrical signals that drive the heart. Any abnormal change in these spontaneous electrical discharges may cause an arrhythmia. During an arrhythmia, the heart can beat too slowly (bradycardia), too quickly (tachycardia) or erratically (fibrillation).
With AF, there are countless electrical discharges from the atrium that don't start from the SA node, causing the atria to quiver rather than contract. The impulses are sent to the ventricles. Fortunately, all of them aren't able to get past an electrical “gatekeeper” that sits between the atria and ventricles known as the atrioventricular node. But an unpredictable number of uncoordinated impulses will get through, causing the ventricles to contract irregularly. The pulse will also be unsteady, often varying on a beat-to-beat basis. A quivering atrium is a potential site for blood clots to form. If a blood clot leaves the heart and travels to the brain, a stroke can occur. AF is associated with roughly 15 percent of strokes.
AF can occur when a person has no other types of heart disease, but is common with certain types of valve disease and heart failure. AF is also linked to excess thyroid hormone activity, alcohol or caffeine.
Many patients are unaware they have an irregular heart rhythm. In some cases, AF is detected during a routine physical. Unfortunately, some people aren't diagnosed until after a stroke or other complication. The most common symptoms associated with AF and other arrhythmias include:
▪ Palpitations or a feeling of “skipped” beats;
▪ A “fluttering” sensation in the chest or neck (which is what True Hills describes as a “bag of wiggly worms”);
▪ Fainting or near-fainting spells;
▪ Rapid heartbeat or pounding heart;
▪ Shortness of breath; and
▪ Chest pain
“Sometimes arrhythmias can be a little insidious and manifest [only] as fatigue and exercise intolerance or loss of energy,” explains Adam E. Berman, M.D. Director of Cardiac Arrhythmia Ablation Services at the Medical College of Georgia in Augusta. He recommends seeing your doctor if you have “frequent palpitations, a racing, skipping, or fluttering heart rate, or if you're short-winded or have exercise fatigue.
Berman recommends going to the ER if your palpitations are accompanied by fainting or you feel discomfort in your chest, because these symptoms can indicate you are at high risk of more life-threatening arrhythmias and sudden cardiac death, which can occur during a heart attack.
TURN THE BEAT AROUND
There are several available treatments for heart rhythm disturbances. In choosing the best one for you, your doctor will consider the type of arrhythmia you have, whether you have any underlying heart disease, how severe the arrhythmia is, how much it affects your quality of life and your own personal preferences about treatment.
For many patients with AF, symptoms can be controlled with medications designed to slow the heart rate, such as beta-blockers and/or calcium channel blockers. The American Heart Association also recommends aspirin or warfarin to reduce stroke risk. When these treatments don't provide enough control of the symptoms of AF, an anti-arrhythmic medicine is sometimes added to reduce the number of AF episodes and help keep normal sinus rhythm. If this approach does not work, doctors may consider catheter-based radio frequency (RF) ablation, which involves threading an electrode-tipped catheter to the heart to destroy the abnormality causing the rhythm disturbance with RF energy.
Some patients with AF are unstable or symptomatic enough to require electrical cardioversion — an electric shock applied to the chest to jolt heart rhythm back to normal. This procedure is done with sedation and anesthesia.
Figure. Mellanie Tru...Image Tools
Pacemakers (implantable cardiac defibrillators or ICDs) are used to treat AF only when medication has failed to slow the heart beat and the atrioventricular node needs to be destroyed so it can no longer send impulses to the ventricles. A pacemaker is then placed in the ventricle to function as the atrioventricular node would have.
True Hills was first treated with a beta-blocker and an anticoagulant drug, but her AF kept recurring. In 2005, she opted for RF ablation. She hasn't experienced any of the dreaded symptoms since. True Hills, her husband and her 24-year-old son are relieved and thankful. She has made it her life's mission to educate people about AF and other arrhythmias as the founder of the non-profit patient advocacy website www.stopafib.org. She advises patients to figure out what triggers their symptoms — dehydration, overexertion, stress, alcohol, or caffeine — so they can avoid the culprit(s), to take their meds exactly according to the doctor's instructions, and to inform their doctor promptly when they experience symptoms.
True Hills won't get an argument from Cohen: “You may have a symptom of palpitations, and you're not going to know whether it's a life-threatening problem or a benign problem. That's when you should seek medical attention, figure out what it is, and find out if there's anything you can do about it.”
© 2011 American Heart Association, Inc.