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Heart Condition – Long QT Syndrome

After 22 years as an RN, I now write about medical issues and new medical advances. Diet, exercise, treatment, and lifestyle are important.

Heart Normal Electrical Rhythm

Anatomy & Physiology

Anatomy & Physiology

Long QT Syndrome (LQTS)

The long QT syndrome is a serious heart condition that is usually acquired through a genetic mutation; therefore, twins are particularly vulnerable. It also occurs to closely related family members. There are also cases of this disease occurring due to certain medications and medical conditions. This is a rare disorder and experts believe approximately one in 7000 people have LQTS, but they also know it goes undiagnosed quite often. In addition, this disorder causes about 3000 to 4000 sudden deaths in children and young adults annually.

The first abnormal heart rhythm usually occurs by the time an individual is 12 years old and 90% occur by the time the individual is 40 years old. It is rarely diagnosed after 40. It often goes undiagnosed.

This disorder is more common in women than men, and boys often return to normal after puberty. Women are more likely to faint or die suddenly from this disorder during menstruation and shortly after giving birth. Children who are born deaf are also at increased risk.

What is Long QT Syndrome?

Long QT syndrome is a disorder of the heart’s electrical system. The heart may suddenly have an uncontrollable, dangerous arrhythmia, which is usually in response to stress or vigorous exercise. The heart arrhythmia will be a problem if the heart rate or the normal rhythm changes into a potentially lethal one

The Normal Heart Rhythm

The ECG measures the electrical impulses five distinct waves, using P, Q, R, S and T. While the P initiates the heart rate, the space between the start of the Q wave to the end of the T wave equals the time it takes for the heart to contract and refill with blood before the next contraction. Doctors measure the Q–T interval to find out if it occurs in a normal amount of time. The upper time limit of the QT interval accounts for age, sex, regularity and speed of the heart rate.

At this 12 genes associated with LQTS have been discovered so far, but hundreds of mutations within these genes have been identified also. These mutations account for approximately 70 to 75 percent of LQTS cases. Obviously there is much research to be done to fully understand this disorder.

Inherited LQTS

Unfortunately, my nephew’s finance, who is a twin, has recently been diagnosed with this genetic disease and is currently being evaluated. In her case, she has had no symptoms, but her sister has had fainting spells and is being actively treated as they both wait for DNA results.

If you have the genetic version of LQTS, you will have this disorder throughout your life. Not everyone has symptoms, while others are very symptomatic or experience sudden death. There are seven types of this inherited disorder. DNA studies always accompany this diagnosis as it may be inherited from one parent or from both. Obviously if you’ve inherited from both parents the probability of symptoms is greater.

The most common inherited LQTS are called one, two and three. In LQTS 1 exercise, particularly swimming, and emotional stress can trigger arrhythmias. In LQTS2 the extreme emotions, such as a sudden surprise, can also trigger arrhythmias. In LQTS 3 a slow heart rate can trigger arrhythmias, which occurs during sleep.

Normal versus Ventricular Rhythm

Cleveland Clinic

Cleveland Clinic

Medication-Induced and Diseases

There are more than 15 medicines that have been found to cause this disorder. Some of the most common medicines include:

  • Decongestants and antihistamines
  • Diuretics
  • Antibiotics
  • Antidepressants and antipsychotic medications
  • Cholesterol-lowering medications
  • Some diabetes medications

Other causes of this syndrome include; severe vomiting or diarrhea due to the major loss of sodium or potassium in ions from the bloodstream. The disorder will only last until these ion levels normal. Anorexia nervosa, bulimia and some thyroid disorders can also cause a drop in potassium ion levels in the blood.

Heart Rhytm


Heart Problem Symptoms

Many people with LQTS do not have symptoms of heart problems, but for those that do the most common is fainting spells, which can occur when you’re very excited, angry, scared or exercising. Some signs that you’re about to faint include lightheadedness, heart palpitations, irregular heartbeat, weakness and blurred vision, however, warning signs are unusual for these patients.

If the heart rhythm remains erratic the brain becomes deprived of oxygen, so seizures are a symptom. If the heart rhythm does not return to normal and there is no medical intervention accessible, than sudden-death will occur.

What is Long QT Syndrome?

Lifestyle Changes

Patients diagnosed with this disorder will have to make lifestyle changes so they can avoid anything that may trigger an abnormal heart rhythm. Medications that link them the QT interval or lower the potassium blood level are forbidden. Patients are asked to add or potassium to their diets by eating foods, such as bananas or taking a potassium supplement.

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As my niece goes through the diagnostic phase, she is only allowed to take ibuprofen for pain, and there is only one antibiotic that will be allowed if necessary. She has to change her lifestyle completely as she was a runner. She can;t ride on roller coasters or get overly stressed. Her sister has had an implanted heart monitor, so the doctor can be informed if her heart rate becomes to irregular or beats too fast.

Treatment of LQTS

The treatment will depend on the type of LQTS symptoms for each patient. Most medications are limited for these patients as many tend to lengthen the QT interval.

There are some specific medications to avoid once the type of LQTS is verified, such as for patients who have LQTS3. They are usually prescribed a sodium channel blocker medicine, but this is not used for any other types of this disorder. Beta blocker medications are sometimes used to prevent cardiac events for some patients also.

If the doctor finds the patient is at risk for more complications, they will use more aggressive treatments. This might include an implanted device, such as a pacemaker or a cardioverter defibrillator as they control abnormal heart rhythms. Sometimes surgeries are done on the nerves that regulate the heartbeat.


This is obviously a rather frightening disease for anyone as you may have no symptoms at all, then suddenly go into a lethal rhythm and die. As research progresses we certainly hope that patients can be diagnosed prior to having any symptoms, and new treatments will also be developed.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Pamela Oglesby (author) from Sunny Florida on March 26, 2020:

thank you, Peggy, for you good wishes to my ice. So far so goo as they say. This is a fairly rare genetic disease. It may account for the death of some athelics but I am not sure.

Peggy Woods from Houston, Texas on March 26, 2020:

This heart condition might account for some of the young athletes who appeared to be so healthy and then drop dead on a playing field. It does not happen that often, fortunately. It is good your niece now knows what she had to do concerning her lifestyle. Wishing her the best!

Pamela Oglesby (author) from Sunny Florida on August 05, 2014:

imti. I am glad you found this hub informative. Thank you so much for your comments.

Imtiaz Ahmed from Dhaka, Bangladesh on August 04, 2014:

Pamela99 a very interesting post. Thank you for sharing your knowledge about heart with us. Now I know more i knew about hearts. I gave you a Up vote cause the article was very interesting. I will visit more of your pages thank you :)

Pamela Oglesby (author) from Sunny Florida on March 16, 2014:

Diana, I'm glad your husband got the right treatment. I appreciate your comments.

Dianna Mendez on March 15, 2014:

Thank you for sharing such an important topic. My hubby had stents a few years back, the heart is vital to our health and knowing how to keep it healthy makes all the difference.

Pamela Oglesby (author) from Sunny Florida on March 05, 2014:

Liz, This is a rare disease, but since it is often undiagnosed it is always good to be aware. I appreciate your comments.

Elizabeth Parker from Las Vegas, NV on March 05, 2014:

I've never heard of this before but very good to know. Great post!

Pamela Oglesby (author) from Sunny Florida on March 03, 2014:

Jo, I know there is research happening and I'm glad to hear about the Sinapore success. That give me more hope for my neice, her sister and others. Thanks for sharing this information and your comments.

Jo Alexis-Hagues from Lincolnshire, U.K on March 03, 2014:

A very frightening condition indeed. I read somewhere that researchers in Singapore has managed to successfully reverse the effects of a particular gene mutation in Long QT syndrome 2 by using the patient's own stem cells, which is transformed to beating heart cells. If this is possible, now it shouldn't be too long before the drugs will become available, there is always hope. Very interesting article.

Pamela Oglesby (author) from Sunny Florida on March 02, 2014:

DDE, Thank you so much for your comments.

Devika Primić from Dubrovnik, Croatia on March 02, 2014:

You have produced an informative and interesting hub on this condition an eyeopener for many who ignore the signs. You shared useful facts on such a serious health issue.

Pamela Oglesby (author) from Sunny Florida on March 02, 2014:

Alicia, I wanted people to understand the facts of this condition, even though it is rare. Thank you for your comments and the well wishes for by neice.

Linda Crampton from British Columbia, Canada on March 01, 2014:

This is a very informative hub that contains interesting but scary facts. I hope your niece has a good future.

Pamela Oglesby (author) from Sunny Florida on March 01, 2014:

Shauna, Thank you so much for your kind comments. Thank you.

Shauna L Bowling from Central Florida on March 01, 2014:

Pamela, you're doing a world of good by bringing awareness to this condition. I wish your niece the best.

Pamela Oglesby (author) from Sunny Florida on February 28, 2014:

Ruby, Anything that touches the young always touches my heart.,I appreciaate your comments.

Pamela Oglesby (author) from Sunny Florida on February 28, 2014:

Billy, I am surprised that my neice seems to be coping pretty well at this time. Thanks for the comments.

Pamela Oglesby (author) from Sunny Florida on February 28, 2014:

Deborah, It is scary as we know some of those teens that die while playing basketball or football had this disease, but didn't know. Thanks for your comments and best wishes for my neice.

Pamela Oglesby (author) from Sunny Florida on February 28, 2014:

Jackie, I agree with your wish. My nephew's finace, Katie, is taking it pretty well.She is very worried about her twin sister since she has had some serious symptoms. The DNA takes anywhere from 3 to 5 months to be completed, so she won't know anything for sure for quite a while.

Thanks for your comments.

Ruby Jean Richert from Southern Illinois on February 28, 2014:

Usefull and interesting hub. Thre are so many different heart conditions. Too bad this hits the young. Thank you for sharing an informative article Pam...

Bill Holland from Olympia, WA on February 28, 2014:

I can see where that would definitely be frightening. Thanks for the information, professionally delivered as always, Pamela.

Deborah Neyens from Iowa on February 28, 2014:

This is scary stuff, especially to think that common medicines can cause it. My best wishes to your niece. I hope her doctors figure out an effective treatment and that her lifestyle is not overly impacted.

Jackie Lynnley from the beautiful south on February 28, 2014:

This is really serious and I hope the twins mentioned will be alright or caught in time to control it if they have it. Too bad a tube of blood cannot be scanned down a long list of maybes to be checked out so we are not shocked suddenly with things like this in a world we think is moving smoothly. Great info, thank you for sharing it. ^

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