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Cardiac Center of Texas
Vein Clinic of Texas

4201 Medical Center Drive
Suite 380
McKinney, TX 75069

1600 Coit Road
Suite 209
Plano, TX 75075

(p) 972-529-6939
(f) 972-529-6935

Office Hours

Mon - Fri 8:00 a.m. - 5 p.m. CST

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Long QT Syndrome

Long QT Syndrome is a disorder where the heart begins to beat suddenly, violently and arrhythmically during exercise or times of stress. This is because something goes wrong with the electrical component of the heart.

The syndrome is named after an abnormal electrocardiogram or EKG pattern. The EKG records the electrical activity in the heart on a graph that’s available for a doctor or medical professional to study. On the graph, the heartbeat is divided into P,Q,R,S and T waves. There’s an interval between the waves, including the interval between the Q and T wave. The Q-T interval lasts about a third of the cycle, but in people with long Q-T the interval is longer than it should be. Because the biology that controls the heartbeat is delicate and complicated, this long interval can upset the way the heart beats and cause arrhythmias.

Part of the electrical activity of the heart is regulated by ions of calcium, potassium and sodium that flow in and out of tiny ion channels in the cardiac muscle. In people with LQTS these channels might be defective or there may not be enough of them.

With these abnormalities in mind, medical researchers believe that many cases of long QT syndrome are inherited and will be a life time problem. Other people get the condition because of illness or medications. Symptoms of LQTS can be fainting, near drowning if the person is engaged in swimming and a sudden and inexplicable stoppage of the heart.

There are seven kinds of inherited Long QT syndrome but only 1, 2 and 3 are common. LQTS 1 is triggered when the person is undergoing emotional stress or is exercising. If it’s triggered by exercise, it’s likely to be caused by swimming. In LQTS 2, the problem can be brought on by violent emotions. In LQTS 3 a slow heartbeat while the person’s sleeping can lead to the arrhythmias.

Fortunately, there are treatments and healthy habits that can help a person with LQTS. Patients should avoid strenuous exercise and shocks. They can also benefit by adding potassium to their diet and taking beta or channel blockers. They should also not take certain medications. Some people with LQTS wear pacemakers. They can also opt for an implantable cardioverter defibrillator to help regulate their heart rhythms. In a last resort, the patient might need life-saving surgery. During this surgery, the doctor severs nerves that tell the heart to beat too fast in the face of stresses both emotional and physical.