Many people with long QT syndrome (LQTS) do not have any symptoms related to their condition. However, because of the risk of sudden cardiac death, physicians may choose to treat all patients.

The first line of treatment for LQTS is beta blockers, which lessen the number of nerve impulses that occur within the heart and blood vessels. This reduction in heart rate lessens the blood force within the vessels and lowers the overall rate of work the heart performs. Slowing the heart rate can help mitigate the dangerously fast beat that can come about in times of stress, fear or exertion. This type of treatment is effective in preventing fainting (syncope) in about 75 to 90 percent of LQTS patients. Beta blockers are also effective in pregnant patients.

For patients not helped by medication, an artificial pacemaker or implantable cardioverter defibrillator (ICD) may be implanted under the skin in the chest. These devices can monitor and, if necessary, correct a potentially fatal abnormal heart rhythm (arrhythmia). In extremely difficult to treat cases, the patient may be recommended for a special surgery known as left cardiac sympathetic denervation. During this surgery, the physician removes very specific parts of the cardiac nerve structure, which reduces frequency of arrhythmias. This surgery is performed more frequently outside the United States.

Lifestyle changes related to physical activity are also important for someone diagnosed with LQTS. Although exercise does not need to be given up entirely, hard or strenuous exercise can be dangerous. It is also suggested that people with LQTS not be alone when engaging in those physical activities recommended by their physician. Teachers, friends, neighbors and anyone else in contact with the individual, especially if he or she is a child or young adult, should be aware of the situation, and plans should be in place in case of an emergency medical event. Time is of the essence in cases of oxygen deprivation to avoid sudden cardiac death. All LQTS patients should also be fully aware of the symptoms that could warn of decreased blood flow to the brain, so they can rest or seek help as needed.

LQTS patients need to be careful about which prescription and over–the–counter medications they take. Some medications are known to prolong the Q–T interval. They include certain antihistamines and antibiotics, and some drugs to treat heart disease, cancer, depression or gastrointestinal disorders.

The vast majority (about 85 percent) of LQTS cases cannot be prevented because the condition is inherited. If one parent has LQTS, then each of his or her children has a 50 percent chance of inheriting the condition. If both parents have LQTS, then each of their children has a 75 percent chance of inheriting the condition. Boys and girls are at equal risk. People should be tested for LQTS if it runs in their family, or if any family members have had unexplained fainting spells.

Although uncommon, LQTS can also be acquired, usually from medication therapy. Medications that have been associated with LQTS include antiarrhythmics. In this case, the first line of treatment also involves discontinuing the offending drug.