What does long QT mean?
The QT interval on an electrocardiogram reflects the time it takes for the ventricles of the heart to contract and then regain electrical charge. If this process is delayed, some of the cells may be excited prematurely, and a dangerous special type of ventricular tachycardia is triggered. It often stops on its own, causing only fainting, but sometimes it progresses to ventricular fibrillation. The duration of the interval depends on the pulse rate, so it is always recalculated using the formula. You should not evaluate elongation from one image without a doctor: the value may change at different times of the day.
- QT reflects restoration of ventricular electrical activity
- Extension creates conditions for dangerous arrhythmia
- The value is adjusted according to heart rate
- The indicator may change during the day
- The assessment is carried out by a cardiologist
Congenital and acquired variants
The congenital syndrome is caused by changes in the genes encoding ion channels of the heart cell and is inherited in the family. Different genetic variants are characterized by their own provoking situations: in some people, fainting occurs during physical activity and especially when swimming, in others it occurs with a sharp sound, such as the ringing of an alarm clock, in others it occurs during sleep and at rest. Acquired lengthening is more often associated with medications: many drugs of different groups have this effect, and the risk increases when they are combined, with loss of potassium and magnesium, and in the elderly.
- Congenital forms with familial accumulation of cases
- Different provocateurs for different genetic variants
- Drug-induced QT prolongation
- Potassium and magnesium deficiency due to vomiting, diarrhea, diuretics
- Anorexia and strict diets
- Diseases of the thyroid gland and heart
Symptoms
Many people with long QT experience no sensation and the change is discovered incidentally on a routine electrocardiogram. Others experience episodes of palpitations, blurred vision, dizziness and fainting. A very important feature: fainting in this syndrome is often accompanied by convulsions, and it is mistakenly mistaken for an epileptic attack, prescribing anticonvulsants instead of a cardiac examination. The connection with stress, fear or loud noise, rapid recovery of consciousness and family history help to distinguish.
- Often - no complaints
- Fainting during exertion, fright, loud noise
- Fainting during sleep in some cases
- Palpitations
- Cramps during fainting
- Sudden cardiac arrest as the first manifestation in rare cases
Survey
The basis is an electrocardiogram with the correct measurement of the interval and daily monitoring, which shows changes during the day and during exercise. Echocardiography is needed to rule out structural heart disease. Be sure to determine potassium, magnesium, calcium, and evaluate thyroid function. The doctor carefully collects medical history and family history: cases of sudden death at a young age, unexplained fainting, and drowning in relatives are very significant. If a congenital syndrome is confirmed, genetic research and examination of close relatives are recommended.
- ECG with corrected QT measurement
- Daily ECG monitoring
- Echocardiography
- Potassium, magnesium, calcium, TSH
- Analysis of all medications taken
- Family history and examination of relatives
- Genetic research according to indications
Treatment and safety rules
For congenital syndrome, the basis of treatment is beta blockers, which reduce the risk of arrhythmia; You need to take them constantly, without missing a dose. In case of high risk and previous cardiac arrest, an implantable cardioverter-defibrillator is installed. With acquired lengthening, the main thing is to discontinue or replace the drug that caused the change and replenish potassium and magnesium. All patients should have a list of QT prolonging medications and show it to any doctor, including their dentist. Sports activities and swimming are discussed individually; It is useful for relatives to learn cardiopulmonary resuscitation skills.
- Constant use of beta blockers as prescribed by a cardiologist
- Discontinuation or replacement of drugs that prolong QT
- Maintaining normal potassium and magnesium levels
- List of prohibited drugs with you
- Caution with vomiting, diarrhea and strict diets
- Discussion of sports and swimming with a cardiologist
- Training loved ones in cardiopulmonary resuscitation
- Examination of first-degree relatives
