Once the genetic cause is identified then at risk family members can consider genetic testing to determine if they are at risk as well. If congenital LQTS is suspected our genetic counselors can assist you with genetic testing to confirm the underlying cause. Implantable monitor: a tiny event monitor inserted under your skin, worn for several years to record events that only seldom take place Holter monitor: a portable ECG you wear continuously for one to seven days to record your heart rhythms over timeĮvent monitor: a portable ECG you wear for one or two months, which records only when triggered by an abnormal heart rhythm or when you manually activate it Tests for magnesium, potassium and blood calcium deficiency (electrolyte imbalances) On-site Diagnostic TestsĮlectrocardiogram (ECG or EKG): wires taped to various parts of your body to create a graph of your heart’s electrical rhythmĮxercise stress test: ECG recorded while strenuously exercising Other tests provide monitoring at home as you follow your daily routine. Some diagnostic tests take place on site in a doctor’s office or hospital. Rarely, grapefruit juice may increase the risk of a dangerous cardiac event when combined with a triggering drug. If you have been diagnosed with LQTS, consult your physician about which drugs put you at risk. Triggering Conditions Electrolyte ImbalancesĪ history of heart disease, including heart failure, heart attack, left ventricular hypertrophy or bradycardiaĪ wide variety of drugs may lengthen the QT interval.
Sometimes the symptoms are caused by not one but several triggers - for example, a genetic mutation combined with a medication that prolongs the QT interval. Stopping the medication and/or correcting the condition causing LQTS often resolves the issue. Acquired LQTSĪcquired long QT syndrome is the result of conditions, medications or events that prolong the QT interval. This may be because their LQTS is very mild or because they have not been exposed to the “right” combination of triggering conditions or medications.Īnyone diagnosed with congenital LQTS should inform family members so they can be tested. On the other hand, there are people whose family members have LQTS and who share the genetic mutation, but never have symptoms themselves. Boys are more likely than girls to have a dangerous cardiac episode from LQTS by age 15. Babies have even been diagnosed in utero. Sodium and potassium help generate electricity inside the cells.Ĭhildren may be diagnosed in infancy or later, either because they go through an episode of seizures or cardiac arrest, or because of family members known to have the mutation. People with congenital LQTS have a genetic mutation that affects sodium or potassium channels in the heart. LQTS can be categorized as congenital (inherited, genetic) or acquired (triggered by some condition, medication or event). Though it often stops on its own, torsades de pointes that persists can lead to ventricular fibrillation, which may cause sudden cardiac death. The ventricles beat more than 200 times per minute, resulting in a sudden drop in blood pressure. LQTS can cause torsades de pointes, an irregular rhythm in the ventricles - the lower chambers of the heart. Seizure-like activity caused by lack of blood flow to the brain Or they may be diagnosed when family members are found to have genetic LQTS. Some people have no symptoms and are only diagnosed when they get an ECG for other reasons. Abnormalities in the heart cells can slow the process of electrical recharging, prolonging the QT interval as shown on an ECG. Letters Q through T correspond to the heart cells’ “recharging” (repolarizing) after a muscle contraction. Doctors name the different waves on the ECG graph P, Q, R, S and T. The term “long QT” refers to the heart’s electrical activity as graphed on an electrocardiogram (ECG or EKG). The electrical current, generated by a chemical process within the muscle cells, makes the heart contract to pump out blood. What happens during LQTS?Įlectricity is what causes the heart muscle to beat.
Torsades de pointes may result in syncope (fainting) or sudden cardiac death.
Long QT syndrome (LQTS) is an abnormal feature of the heart’s electrical system that can lead to a potentially life-threatening arrhythmia called torsades de pointes (pronounced torsad de pwant).