Because the heart's electrical system is complicated, diagnosing abnormal heart rhythm (arrhythmias) can be difficult and requires heart rhythm experts who use special testing equipment. To find the problem, a doctor will take a medical history, ask about symptoms, give a thorough physical exam, and order specific tests.
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The following are various tests that can be conducted.
Electrodes leading to a special machine are attached to the legs, arms, and chest with sticky patches to record the electrical signals that create heart rhythms.
A special imaging machine with a microphone-like attachment creates a videotaped image of the heart, showing the four chambers, valves and movements.
To detect abnormal heart rhythms, patients wear a recorder about the size of a deck of cards, with electrodes attached to their chest by sticky patches for 24-48 hours.
Patients carry a portable EKG recorder for up to 30 days so they can make a one- to two-minute recording of their heart rhythm when they have symptoms. Also the size of a deck of cards, the recorder is helpful for patients with who have short-lived or infrequent symptoms.
This test searches for reasons for fainting, or temporary passing out (syncope). Heart rhythm and blood pressure are carefully monitored while the patient rests on a special table. The table tilts the patient upright at a 70-80 degree angle for 30-45 minutes. If the patient faints, it usually means that he or she has a condition called vasovagal or neurocardiogenic fainting, which is not life threatening.
Under safe conditions in a hospital or lab, thin tubes called electrode catheters are placed into veins in the groin or neck area and passed into the heart through a patient's veins to record its electrical signals. An electrophysiologist (EP), a heart rhythm specialist, studies the speed and flow of those signals to pinpoint areas in the heart's muscle that cause rhythm problems. This study can diagnose potentially life-threatening slow and fast heart rates.
A thin hollow tube, called a catheter, is placed into a blood vessel and, using an X-ray machine, passed into the heart. Special heart catheters can gather tissue samples of heart muscle that may be damaged, measure the pressure in the heart, show blockage in the blood vessels of the heart, or confirm heart valve disease.
Arrhythmias may come and go. Since many heart rhythm problems come and go, they may not show up during a test. Sometimes the heart needs to be monitored over time. Specialists may also cause abnormal heart rhythms in a safe environment to find the problem.
Symptoms can be hard to identify. People with arrhythmias may not feel any symptoms, or they may have symptoms that seem unrelated to the heart, such as lightheadedness, fainting or shortness of breath. Doctors who specialize in heart rhythm problems (electrophysiologists) run special tests to see if those symptoms are caused by problems in the heart's electrical system or by other types of heart disease.
Some arrhythmias are caused by factors unrelated to the heart. Medications, metabolic diseases, the environment, diet, and stress can cause abnormal heart rhythms in otherwise healthy people. Specialists take all of these factors into account as they choose tests to uncover the true cause of an arrhythmia.