What is Long QT syndrome?

It is a cardiac pathology in which the heart beats rapidly and the rhythm is altered, which can cause sudden fainting or seizures and sudden death in young people.

Long QT syndrome, also known as heart conduction disorder, appears due to changes in the heart’s electrical system.

There are a series of conditions that can contribute to its appearance, such as:

Family members with this condition.
Electrolyte imbalances due to diarrhea and/or vomiting.
History of cardiac arrest.
Drugs that produce extended QT intervals.
Heart medications.
Medical conditions, such as low levels of calcium, magnesium, and potassium; stroke or bleeding in the brain, and hypothyroidism, among others.
Eating disorders that cause electrolyte imbalances.

People who suffer from long QT syndrome usually develop symptoms before turning 40. If the disorder is congenital, symptoms may arise during the first weeks or months of life.

Long QT syndrome is classified, depending on the cause, into:

Congenital long QT syndrome: changes in DNA transmitted from parents to children. There are two types:
- Romano-Ward syndrome, common in people who inherit a single genetic variant from one parent.
- Jervell and Lange-Nielsen syndrome, in which children receive altered genetic variants from both parents.
Acquired long QT syndrome: occurs as a result of a pre-existing disease or the intake of some medication.

Signs and symptoms Long QT syndrome

Daze.
Weakness.
Palpitations.
Blurred vision.
Fainting.
Seizures.

The greatest risk of long QT syndrome is ventricular fibrillation, as well as sudden death.

Diagnosis and treatment Long QT syndrome

Once the doctor analyzes your symptoms and clinical history, they will perform a physical examination and request a series of tests to rule out other conditions and make an accurate diagnosis, including:
Electrocardiogram.

Holter monitor.
Stress test.
Genetic testing.

Treatment consists of taking medications that help prevent irregular heartbeats and changes in lifestyle.

Implantation of a device to control heart rhythm may be required in more severe cases.

At the Cardiovascular Center, we offer you a wide range of prevention, diagnosis, timely treatment, and follow-up services to care for you through a comprehensive and multidisciplinary care model. Come to us, we want to hear your heart.

Related centers and departments

Cardiovascular Center
Radiology and Molecular Imaging
Clinical Laboratory

Fuentes:

texasheart.com
nhlbi.nih.gov
revespcardiol.org
secardiologia.es
mayoclinic.org
medlineplus.gov
msdmanuals.com
medigraphic.org
Estévez RY, Domínguez SR, Padilla BTD, et al. Síndrome de QT largo en la embarazada con el uso de la oxitocina. CorSalud. 2021;13(2):195-199.
Fernández DD, Cruz BR, Cabrera PAJ, et al. Factores de riesgo asociados a síndrome QT largo en anestesia cardiovascular. Revista Cubana de Anestesiología y Reanimación. 2017;16(3):1-16.
Gallardo MY, Puga BMV, Román RPA, et al. Síndrome de QT largo y embarazo. Experiencia en Cuba. Rev Cubana Cardiol Cir Cardiovasc. 2018;24(2):.

How can we help you?

The dissemination of the content of this material is for informational purposes only and does not replace, under any circumstance or condition, a consultation with a specialist doctor, for which the ABC Medical Center is not responsible for the different use that may be given to it. If you require more information related to the subject, we suggest you contact the specialist doctor you trust directly.

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Comparison of COVID-19 vaccines

Pfizer-
BioNTech

Pfizer-BioNTech

What is its effectiveness and what does it refer to?

Vaccine type: mRNA
Effectiveness: 95% after the second dose in the prevention of symptomatic COVID-19.

No Does not contain egg, latex, or preservatives.

How many doses are needed?
Two doses are needed, at least 21 days apart (or up to six weeks apart, if necessary).

Who should or shouldn’t get the vaccine?
People who should receive the vaccine are those over 16 years old.
People who should not receive the vaccine are those who have a history of anaphylactic shock (severe allergy) or who are allergic to any component of this vaccine such as polyethylene glycol (PEG) or polysorbate.

What are the possible side effects of the vaccine?
Pain where the injection was given, fatigue, headache, muscle pain, chills, joint pain, fever, nausea, malaise, and swollen lymph nodes.

How long will it take for me to be protected and what does it protect me from?
After 14 days of having the complete scheme (after the administration of the 2nd dose), the protection period is still under study. It protects us from serious COVID-19 or requiring hospitalization.

Moderna

What is its effectiveness and what does it refer to?

Vaccine type: mRNA
Effectiveness: 94.5% after the second dose in the prevention of symptomatic COVID-19.

Does not contain egg, latex, or preservatives.

How many doses are needed?
Two doses are needed, at least 28 days apart (or up to six weeks apart, if necessary).

Who should or shouldn’t get the vaccine?
People who should receive the vaccine are those over 18 years old.
People who should not receive the vaccine are those who have a history of anaphylactic shock (severe allergy) or who are allergic to any component of this vaccine.

What are the possible side effects of the vaccine?
Pain where the injection was given, fatigue, headache, muscle pain, chills, joint pain, fever, nausea, and swollen lymph nodes in the arm in which you received the injection.

Janssen/
Johnson
& Johnson

Janssen/ Johnson & Johnson

What is its effectiveness and what does it refer to?

Vector-based vaccine.
Effectiveness: 72.0% in the prevention of symptomatic COVID-19.
85% in the prevention of severe COVID-19.

Does not contain egg, latex, or preservatives./strong>

How many doses are needed?
Only one dose in needed.

What are the possible side effects of the vaccine?
Pain where the injection was given, headache, fatigue, muscle pain, chills, fever, and nausea.

How long will it take for me to be protected and what does it protect me from?
After 28 days of having the complete scheme (the last dose applied), the protection period is still under study. It protects us from 85% serious COVID-19 or requiring hospitalization.

AstraZeneca
and
Oxford
University

AstraZeneca and Oxford University

What is its effectiveness and what does it refer to?

Adenovirus vector-based vaccine.
Effectiveness: 82% after the second dose in the prevention of symptomatic COVID-19.

How many doses are needed?
Two doses are needed, at least 56 days apart (or up to 84 days apart, if necessary).

What are the possible side effects of the vaccine?
Pain where the injection was given, fatigue, headache, myalgia, arthralgia, and fever, which were mild to moderate in intensity and disappeared within 48 hours of vaccination.

Sputnik V

What is its effectiveness and what does it refer to?

Adenovirus vector-based vaccine.
Effectiveness: 92% after the second dose in the prevention of symptomatic COVID-19.

How many doses are needed?
Two doses are needed, at least 21 days apart (or up to six weeks apart, if necessary).

What is Long QT syndrome?

Signs and symptoms Long QT syndrome

Diagnosis and treatment Long QT syndrome

Related centers and departments

Fuentes:

Index

Specialist in Long QT syndrome