long QT syndrome

Long QT Syndrome (LQTS) Description

Long QT syndrome (LQTS) is a heart condition that affects the electrical system of the heart, causing it to take longer than normal to recharge between heartbeats. This can lead to potentially life-threatening arrhythmias.

• Electrical System Issue: LQTS is characterized by an abnormal prolongation of the QT interval on electrocardiograms (ECGs), which measures the time it takes for the heart's electrical system to recharge.
• Symptoms: People with LQTS may experience fast, erratic heartbeats when exercising or experiencing emotional excitement, leading to fainting or seizures.
• Causes: LQTS is usually caused by a faulty gene inherited from parents, which can affect how the body works and what parts of you are like (e.g., eye color or hair texture).
• Risk: If left untreated, LQTS can lead to cardiac arrest and sudden death due to paroxysmal ventricular arrhythmia.

Key Facts:

• LQTS is an inherited heart problem that affects how the heart beats.
• It can cause fainting or fits (seizures) in some people.
• A person with LQTS may experience fast, erratic heartbeats when exercising or experiencing emotional excitement.
• LQTS is typically characterized by a prolongation of the QT interval on ECGs and by the occurrence of syncope or cardiac arrest.

References:

1. [1] Long QT syndrome refers to an issue with your heart's electrical system taking longer than normal to recharge between heartbeats.[2]
2. LQTS is typically characterized by a prolongation of the QT interval on the ECG and by the occurrence of syncope or cardiac arrest, mainly due to torsades de pointes (TdP).[4]
3. A person with long QT syndrome may experience fast, erratic heartbeats when exercising, or at times of emotional excitement.[5]
4. LQTS is usually caused by a faulty gene inherited from your parents.[8]

Common Signs and Symptoms of Long QT Syndrome

Long QT syndrome (LQTS) is a rare genetic disorder that affects the heart's electrical system, leading to abnormal heart rhythms. The most common symptoms of LQTS include:

• Fainting (Syncope): A sudden loss of consciousness or fainting spell, often triggered by strong emotions, exercise, or sudden noises [1][2][3][4]
• Chest Fluttering (Palpitations): A fluttering or irregular heartbeat in the chest [5][6]
• Shortness of Breath or Chest Pain: Difficulty breathing or experiencing chest pain during physical activity or emotional stress [5][7]
• Lightheadedness that Comes and Goes: Feeling dizzy or lightheaded, often without warning [5][8]
• Near-Drowning or Drowning Incidents: In some cases, LQTS can lead to sudden cardiac arrest, which may result in near-drowning or drowning incidents [6]

Other symptoms of LQTS may include:

• Seizure-like Activity: Lack of blood flow to the brain can cause seizure-like activity [3]
• Stress-Induced Symptoms: Stress, strenuous exercise, or sudden noises can trigger symptoms [4][8]
• Slow Heart Rate during Sleep: A slow heart rate during sleep may be a symptom of LQTS [4]

It's essential to note that these symptoms can vary in severity and frequency among individuals with LQTS. If you suspect you or someone else has LQTS, it's crucial to consult a medical professional for proper diagnosis and treatment.

References: [1] - Search result 1 [2] - Search result 2 [3] - Search result 3 [4] - Search result 4 [5] - Search result 5 [6] - Search result 6 [7] - Search result 9 [8] - Search result 8

To diagnose long QT syndrome (LQTS), several diagnostic tests can be performed.

Electrocardiogram (ECG): An ECG records your heart's rhythm and is often the first test used to diagnose LQTS. A healthcare professional may recommend an ECG if you have symptoms such as fainting or palpitations [4].

Genetic Testing: Genetic testing can identify the mutation responsible for LQTS. This test is usually recommended for patients with a clinical or electrocardiographic (ECG) presentation of LQTS [3]. Next-generation sequencing can detect single nucleotide and copy number variants in 10 genes associated with LQTS [8].

Schwartz Score: The Schwartz score is a diagnostic criteria used to determine the likelihood of LQTS. A score ≥3.5 points indicates definite LQTS, while a score between 2.0-3.4 points suggests an intermediate probability of LQTS [5].

Other on-site diagnostic tests that may be performed include:

• Electrocardiogram (ECG or EKG): This test records your heart's electrical rhythm using wires taped to various parts of your body [6].
• Genetic testing: This test can identify the mutation responsible for LQTS and is usually recommended for patients with a clinical or electrocardiographic presentation of LQTS.

References: [3] Nov 29, 2017 — Patients with a clinical or electrocardiographic (ECG) presentation of long QT syndrome (LQTS) need genetic testing to identify the mutation. [4] Diagnosing long QT syndrome ... A GP may recommend you have an ECG and refer you to a heart specialist (cardiologist) if: ... [5] by AAM Wilde · 2022 · Cited by 143 — Diagnostic criteria for long QT syndrome (LQTS) (the 'Schwartz-score'). [6] On-site Diagnostic Tests · Electrocardiogram (ECG or EKG): wires taped to various parts of your body to create a graph of your heart's electrical rhythm. [8] This test utilizes next-generation sequencing to detect single nucleotide and copy number variants in 10 genes associated with long QT syndrome (LQTS).

Medications Used to Treat Long QT Syndrome

Long QT syndrome can be effectively managed with various medications, which are often prescribed as a first-line treatment.

• Beta blockers: These medications, such as propranolol or nadolol, are commonly used to control heart rhythm and prevent abnormal heartbeats. They work by blocking the effects of adrenaline on the heart, thereby reducing the risk of life-threatening arrhythmias [1][2].
• Potassium supplements: Maintaining a good potassium level can also be beneficial in treating LQT2, particularly when combined with beta blocker medication [9].

In some cases, other medications may be prescribed to help manage symptoms and prevent complications. These include:

• Mexiletine: This anti-arrhythmic medication may be used to treat abnormal heart rhythms associated with long QT syndrome [8].
• Potassium and/or spironolactone: In certain situations, potassium supplements or spironolactone (a diuretic) may be prescribed to help regulate electrolyte levels and prevent arrhythmias [8].

It's essential for individuals with long QT syndrome to work closely with their healthcare provider to determine the most effective treatment plan. Regular monitoring of heart rhythm and medication adjustments as needed can help ensure optimal management of this condition.

References:

[1] Jul 19, 2024 — This surgery may be done if you have long QT syndrome and continuing heart rhythm changes but beta blockers don't work for you. It doesn't cure ... (Search Result 1) [2] Most people with inherited long QT syndrome will need treatment with medicines. Beta blockers, such as propranolol or nadolol, may be prescribed to help control ... (Search Result 4) [3] by AAM Wilde · 2022 · Cited by 143 — As indicated, the cornerstone of management of LQTS patients is ß-blocker therapy (figure 5). The non-selective ß-blockers nadolol and propranolol have been ... (Search Result 6) [4] by PJ Schwartz · Cited by 4 — Outline · - Other pharmacologic therapies · Potassium and/or spironolactone · Mexiletine · - Left cardiac sympathetic denervation · - Implantable cardioverter- ... (Search Result 8) [5] LQT2 can be treated moderately well with beta blocker medication, but treatment may be improved by also maintaining a good potassium level. Of the three major ... (Search Result 9)

Differential Diagnosis of Long QT Syndrome

Long QT syndrome (LQTS) is a rare genetic disorder that affects the heart's electrical system, leading to prolonged QT intervals on an electrocardiogram (ECG). When diagnosing LQTS, it's essential to consider other conditions that may cause similar symptoms. Here are some differential diagnoses for long QT syndrome:

• Drug-induced QT prolongation: Certain medications can prolong the QT interval, making it challenging to diagnose LQTS [1][2].
• Electrolyte disturbances: Abnormal levels of electrolytes such as potassium, calcium, magnesium, and sodium can cause QT prolongation [3].
• Congenital conditions: Jervell and Lange-Nielsen syndrome, Romano-Ward syndrome, and idiopathic LQTS are congenital forms of the disorder [4][5].
• Acquired conditions: Metabolic disorders, such as hypokalemia or hyperkalemia, can cause acquired LQTS [6].
• Other cardiac conditions: Brugada syndrome, short QT syndrome, and WPW (pre-excitation) are other cardiac conditions that may be considered in the differential diagnosis of LQTS [7][8].

References:

[1] Conditions to consider in the differential diagnosis of long QT syndrome (LQTS) include drug-induced... (Search Result 1)

[2] Other causes of QTc interval prolongation to be considered: Drug-induced QT prolongation (See ... (Search Result 2)

[3] Electrolyte disturbances such as hyperkalaemia, hypocalcaemia, hypoglycaemia, hypokalaemia, and hypomagnesemia can cause QT prolongation. (Search Result 3)

[4] Congenital. Jervell and Lange-Nielsen syndrome (including "channelopathies"); Romano-Ward syndrome; Idiopathic. Acquired. Metabolic disorders. (Search Result 4)

[5] Other conditions to consider in the differential diagnosis of long QT syndrome include the following: Brugada syndrome. Short QT syndrome. (Search Result 6)

[6] LQTS is typically characterized by a prolongation of the QT interval on the electrocardiogram (ECG) and by the occurrence of syncope or cardiac arrest, mainly ... (Search Results 7 & 8)

[7] Other causes of acquired LQTS include electrolyte abnormalities, eating disorders, coronary artery disease, and bradyarrhythmias. (Search Result 9)