Inborn syndrome of the extended QT interval

Description:

The syndrome of the inborn extended interval of QT represents rare pathology of the neonatal period though its true frequency remains to the unknown.
The extended QT interval registered at newborns in the first week of life often is associated with a syndrome of sudden death (SIDS). It can lead to developing of zhizneugrozhayemy ventricular arrhythmias. It is noticed that at the newborn children who died from SIDS, QT interval on average equaled 0,435±0,45 ms. The smaller duration of an interval of QT (0,400±0,20 ms) gives already high degree of neonatal survival.

Symptoms of the Inborn syndrome of the extended QT interval:

Initial clinical symptoms of an inborn syndrome of the extended interval of QT include syncopal states (69%), premature sudden death (26%), suffocation attacks (5%). One of manifestations of a syndrome of the extended QT interval pre-natal fruits can have a sinus bradycardia. At a fruit at the time of delivery at the inborn extended interval of QT the irregular cordial rhythm, and after the birth — returnable polyfocal ventricular tachycardia can be observed. In the subsequent time at such babies, except the extended QT interval, on an ECG disturbance of a configuration and incidentally arising inverted teeth T. Opisan a case of an inborn syndrome of the extended QT interval in combination with inversion of teeth in T, the intermittent AV-block 2:1, ventricular arrhythmia and cases of sudden death of one of members of this family come to light.
Electrocardiographic screening at newborns in the first days of life helps to reveal children with the extended interval of QT and threatened on SIDS.
Measurement on an ECG of an interval of JT, instead of QT interval, is more sensitive method reflecting a phase of ventricular repolarization, especially patients with inborn lengthening of an interval have QT.

The exercise tolerance test at a part of babies reveals the hidden lengthening of an interval of QT with the maximum increase in QT in the 2nd minute after loading, in certain cases arise change and a tooth of T.

The reasons of the Inborn syndrome of the extended QT interval:

In genesis of this syndrome genetic defect with defective function of intracellular potassium channels lies. There is an opinion that the extended interval of QT can be result of inborn defects of development of some departments of a sympathetic nervous system of heart. In 60% of cases the syndrome has hereditary character.

Treatment of the Inborn syndrome of the extended QT interval:

Stopping of the disturbances of a heart rhythm which resulted from the extended QT interval is successfully carried out by propranolol or propafenony. Use of Spironolactonum and potassium diet also gives good therapeutic effect.

The forecast at this syndrome in a bolypistvo of cases remains not known. It is noticed that bradycardia less than 60 reductions a minute during an antenatal life, bystry reduction of a cordial rhythm after the birth, and also the fruit birth with an edematous syndrome are bad predictive signs. Despite use of modern beta-blockers, children can not experience infantile age.