For this post and in the weeks ahead, we are going to be schooled on the obscure, lesser known reasons for needing a pacemaker or defibrillator.
Definition Long QT syndrome (LQTS) is a heart rhythm disorder that can potentially cause fast, chaotic heartbeats. These rapid heartbeats may trigger a sudden fainting spell or seizure. In some cases, your heart may beat erratically for so long that it can cause sudden death.
You can be born with a genetic mutation that puts you at risk of long QT syndrome. In addition, certain medications and medical conditions may cause long QT syndrome.
Long QT syndrome is treatable. You may need to limit your physical activity, avoid medications known to cause prolonged Q-T intervals or take medications to prevent a chaotic heart rhythm. Some people with long QT syndrome need surgery or an implantable device.
Symptoms Many people with long QT syndrome don’t have any signs or symptoms. They may be aware of their condition only from results of an electrocardiogram (ECG) performed for an unrelated reason, because they have a family history of long QT syndrome or because of genetic testing results.
For people who do experience signs and symptoms of long QT syndrome, the most common long QT symptoms include:
- Fainting. This is the most common sign of long QT syndrome. In people with long QT syndrome, fainting spells (syncope) are caused by the heart temporarily beating in an erratic way. These fainting spells may happen when you’re excited, angry, scared or during exercise. Fainting in people with long QT syndrome can occur without warning, such as losing consciousness after being startled by a ringing telephone.Signs and symptoms that you’re about to faint include lightheadedness, heart palpitations, irregular heartbeat, weakness and blurred vision. However, in long QT syndrome, such warning signs before fainting are unusual.
- Seizures. If the heart continues to beat erratically, the brain becomes increasingly deprived of oxygen. This can then cause generalized seizures.
- Sudden death. Normally, the heart returns to its normal rhythm. If this doesn’t happen spontaneously and paramedics don’t arrive in time to convert the rhythm back to normal with an external defibrillator, sudden death will occur.
Signs and symptoms of inherited long QT syndrome may start during the first months of life, or as late as middle age. Most people who experience signs or symptoms from long QT syndrome have their first episode by the time they reach age 40.
Rarely, signs and symptoms of long QT syndrome may occur during sleep or arousal from sleep.
You should see your doctor if you suddenly faint during physical exertion or emotional excitement or after use of a new medication.
Because long QT syndrome can occur in families, see your doctor to be tested for long QT syndrome if a first-degree relative (parent, sibling or child) has been diagnosed with long QT syndrome.
Tests and Diagnosis If your doctor suspects that you have long QT syndrome, you may need to have several tests to confirm the diagnosis. These include:
- An electrocardiogram (ECG). In this noninvasive test, small probes are taped to your chest to monitor the waves of electrical impulses in your heart. The probes transmit the waves to a computer screen or printout for your doctor to see. You may have this test while at rest or while exercising by running on a treadmill or pedaling a stationary bike.
- Ambulatory ECG monitoring. This test, also called Holter monitoring, is used to monitor your heart for rhythm irregularities during normal activity for an uninterrupted 24-hour period. During the test, electrodes attached to your chest are connected to a portable recorder that attaches to your belt or is carried by a shoulder strap. The recorded information can then be analyzed to check for heart rhythm irregularities, such as prolonged Q-T intervals.
- Event ECG recording. This is similar to the ambulatory ECG except that you may need to wear a portable ECG recorder for days or weeks as it records your heart rhythms.
While some people with suspected long QT syndrome have a visibly lengthened Q-T interval on an ECG, others don’t, making the condition more difficult to diagnose. Other testing may then be necessary:
- A nonexercise (medication) stress test. This ECG test is performed while you’re given a medication that stimulates your heart in a way similar to exercise. The medication is given through a vein in your arm and may include epinephrine (adrenaline). Adrenaline is a substance that your body releases in response to stress. In this stress test, doctors monitor the effects of the adrenaline on the way your heart recharges. This test can unmask in some people what’s known as concealed long QT syndrome, which is a normal Q-T interval (recharging time) at rest. In some people with long QT syndrome, fainting spells are triggered by sudden bursts of adrenaline in the body, such as are experienced during intense exercise or emotional upset.
- An electroencephalogram (EEG). This test looks for neurological causes of fainting, such as a seizure disorder. The procedure measures the waves of electrical activity the brain produces. Small electrodes attached to your head pick up the electrical impulses from your brain and send them to the EEG machine, which records brain waves.
- Genetic testing. A genetic test for long QT syndrome is available and increasingly covered by private and governmental insurance plans. Current genetic tests for long QT syndrome are capable of finding the genetic cause for about 3 out of every 4 cases of long QT syndrome. Therefore, it’s possible to test negative with the genetic test, but still have long QT syndrome. If your genetic cause of long QT syndrome is discovered through a positive genetic test, then family members can be tested to prove definitively whether they inherited the same genetic mutation.
- A second opinion. You may want to seek a second opinion if your doctor diagnoses you with long QT syndrome. Treatments for long QT syndrome can be life altering, such as avoiding strenuous exercise, taking powerful medications or having surgery. In addition, evidence suggests that misdiagnoses related to this condition are not uncommon — including diagnosing long QT syndrome when it’s not actually present, and overlooking the condition when it is present.
Treatment and Drugs It’s often possible to eliminate drug-induced long QT syndrome simply by switching medications, with your doctor’s direction. Some people, however, may need additional treatment.
Medications used to treat long QT syndrome include:
- Beta blockers. Examples of these heart drugs include nadolol (Corgard) and propranolol (Inderal, Innopran XL). These drugs slow the heart rate and make the dangerous rhythm associated with long QT syndrome less likely. They work by blunting the way a long QT syndrome-affected heart reacts to adrenaline in times of stress, fear or exertion.
- Mexiletine. In people with a form of long QT syndrome called LQT3, taking this anti-arrhythmic drug in combination with propranolol may help shorten the Q-T interval.
- Potassium. Potassium is a mineral in your body, derived from your diet, that’s important for the health of your heart’s electrical system. Potassium supplements may improve the heart’s recharging system and may be helpful for people with certain forms of long QT syndrome.
- Fish oil. Supplementation with heart-healthy fish oil (omega-3 fatty acid) may help stabilize abnormal heart rhythms. You should talk to your doctor before starting fish oil or any other supplements and medications.
Your doctor may suggest treatment for long QT syndrome even if you don’t experience frequent signs or symptoms of the disorder.
If you do need treatment, take the medications your doctor prescribes for long QT syndrome as directed. While medications won’t cure the condition, they provide some protection against potentially fatal disruptions of your heart rhythm. You may need to take a medication such as a beta blocker indefinitely.
Your doctor may consider two other treatments for you:
- A pacemaker or implantable cardioverter-defibrillator (ICD). These devices, which are implanted under the skin of your chest, can stop a potentially fatal arrhythmia. An ICD continuously monitors your heartbeat and will deliver electrical shocks to restore a normal heart rhythm when necessary.
- Left cardiac sympathetic denervation surgery. In this procedure, specific nerves in your chest are surgically removed. These nerves are part of the body’s sympathetic nervous system, which controls automatic functions in the body including regulation of heart rhythm. Left cardiac sympathetic denervation surgery significantly reduces the risk of sudden death.This surgery is generally reserved for people considered at high risk of sudden death, people who do not tolerate their medications or have a fainting spell despite their medications, and people who have an implanted ICD. Left cardiac sympathetic denervation surgery may significantly reduce the frequency of ICD shocks.
In addition to medications or surgery, your doctor may recommend some lifestyle changes to reduce your chances of a long QT syndrome-related fainting spell. These could include avoiding strenuous exercise or contact sports, reducing loud, startling noises, and staying away from situations that could make you excited or angry.
Work with your doctor to balance these lifestyle recommendations against the clear, heart-healthy benefits of an active lifestyle. In some circumstances, it may be possible to stay fully active in sports, including competitive sports, after carefully reviewing the risks and benefits with your doctor.
If your symptoms are mild or don’t occur very often, your doctor may recommend only lifestyle changes as treatment for your condition.
Information provided by Mayo Clinic. Illustrations Bing.com/images
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