Your doctor might suspect an arrhythmia based on your medical history and symptoms that include palpitations or a feeling of “skipped” beats, or if you visit the emergency room because you fainted or experience chest pain.
Your odds of developing an arrhythmia are higher if you have one or more of the following risk factors — some of which can be avoided or managed, and some of which you have no control over.
These are the risk factors you can do something about by improving your diet, losing weight, increasing physical activity levels (but without overdoing it), or getting the appropriate medical treatment to manage:
▪ High blood pressure, high cholesterol, atherosclerosis, diabetes, smoking, obesity, sleep apnea, all of which are associated with heart disease;
▪ Thyroid disorders;
▪ Stimulant drug use (including caffeine);
▪ High or low blood levels of certain electrolytes, including potassium, magnesium or calcium; and
▪ Intensive exercise (particularly, extreme athletes and anorexics).
These are risk factors you can't do anything about, including:
▪ Aging (though keep in mind that arrhythmias can strike at any age);
▪ Heart attack, heart failure, cardiomyopathy, a heart valve problem or any surgery that involves the heart;
▪ Family history of arrhythmia, heart disease or sudden cardiac arrest;
▪ Congenital heart disease, for instance, a hole in the heart that allows deoxygenated blood from the right of the heart to enter the left side; and
▪ Lyme disease or scarlet fever.
In addition, certain medications can cause arrhythmias. For instance, the FDA recently pulled drugs containing propoxyphene (such as, painkillers Darvon and Darvocet) off drugstore shelves because they induced arrhythmias in otherwise healthy people.
“People who have a history of cardiovascular disease need to be aware that they may be at increased risk of developing arrhythmia, and [talk to] their cardiologist. This may include screening for an implantable cardiac defibrillator (ICD), says Adam E. Berman, M.D., Director of Cardiac Arrhythmia Ablation Services at the Medical College of Georgia in Augusta. He also emphasizes that “compliance with heart medications is key.” ICDs are used to treat life-threatening arrhythmias in patients with poor heart function after a heart attack.
If you are at risk of a life-threatening arrhythmia or have been diagnosed with a heart rhythm abnormality, “You [and your family] need to know CPR. You need to know [about] AEDs,” says Todd Cohen, M.D., Director of Electrophysiology and the Pacemaker/Arrhythmia Center at Winthrop-University Hospital. He recommends that you assemble and carry with you at all times a “portable medical information kit” that includes the medications you take and their dosages; a list of allergies; a recent electrocardiogram; and information about any implants, such as stents or a pacemaker or defibrillator. “This information is very helpful in an emergency.”
ARRHYTHMIAS CAN BE ELUSIVE TO DIAGNOSE
Several tests are used to confirm the diagnosis of arrhythmia, and to evaluate the structure, function, and/or electrical activity of the heart.
“There are many tests that provide information regarding the heart. Typically, the most invasive and costly tests do provide more information [whereas] noninvasive tests are less risky, cheaper, and in general may yield less information,” explains Cohen.
A patient who is not considered to be at immediate risk of sudden cardiac arrest will usually undergo noninvasive testing.
An electrocardiogram (also known as an ECG or EKG) uses electrodes placed at different points on the skin around the chest to record the electrical activity of the heart.
An ECG won't diagnose an arrhythmia unless you're actually experiencing one while you're undergoing the test. If your arrhythmia is sporadic, doctors will give you a portable Holter monitor to wear continuously for a day or two to capture any events. In some cases, doctors will have a patient wear a 30- or 60-day monitor that can be activated whenever he or she feels heart palpitations. When monitors fail to pick up the heart rhythm disturbance, doctors will sometimes implant a small loop recorder – a small ECG – under the skin of the upper chest that “can stay there for many years [to] can pick up arrhythmias,” says Berman.
With an echocardiogram (echo), a wand is passed over the chest so that sound waves create an image of the heart that can be used to evaluate its structure and function. This test is like the ultrasound exams that pregnant women undergo to monitor the health and development of an unborn baby. “An ultrasound of the heart is almost always done to assess the pump function of the heart and also to look for any [valve] abnormalities or evidence of congenital heart disease,” says Berman. “Basically, everybody [with symptoms of arrhythmia] gets an echo.”
Patients who feel faint or lightheaded, particularly after rising from sitting or lying down, will be strapped to a table that is tilted into a variety of positions so the doctor can see how the heart rate and blood pressure respond.
When physical activity triggers symptoms, doctors will order a stress or treadmill test. “If the patient has any chest discomfort or angina, [a] stress test makes sure they don't have any evidence of ischemic heart disease,” which is linked to heart attack risk because of narrowing or blockages in the blood vessels that feed the heart, says Berman.
“Ninety-five plus percent of the time, you catch this stuff with some sort of non-invasive monitoring,” notes Berman. But when noninvasive tests are inconclusive or sudden cardiac arrest is a possibility, doctors might opt for invasive testing, such as a coronary angiogram. During the test, a catheter is threaded to the heart from a blood vessel in your arm or leg right into your heart and a dye is injected through the catheter to highlight the structures of the heart. The dye enables the doctor to see your heart in action on a monitor. As an alternative, an electrode-tipped catheter is threaded to the heart to probe the conduction system, find the abnormality causing the rhythm disturbance and destroy it with radio frequency (RF) energy in a procedure known as ablation.
“One particular benefit of an invasive test or procedure is its ability to treat and potentially cure a particular arrhythmia, something noninvasive tests just can't do,” Cohen explains. However, there is a down side: complications of invasive procedures include infection, bleeding, clot formation, perforation and, very rarely, death.
Berman recommends that patients diagnosed with an arrhythmia “seek the care of a heart specialist so that they can have the appropriate treatment started for them because [arrhythmias] can be very disabling.” He adds that with new therapies, symptoms can be controlled to give patients “a good quality of life,” or even cured “in many instances.”
© 2011 American Heart Association, Inc.