Inherited Long QT Syndrome
Long QT syndrome is a genetic condition that affects the heart’s electrical system, causing abnormal heart rhythms. Researchers have identified more than 17 genes associated with this condition, and numerous mutations have been found. Among these genes, three are responsible for over 75 percent of all cases of long QT syndrome. However, it is worth noting that around 20 percent of individuals known to have the congenital form of long QT syndrome test negative for it, while as much as 37 percent of those who test positive have a normal QT interval. This discrepancy suggests that there may be other genetic factors involved. Scientists are currently investigating whether these genes also play a role in infants affected by sudden infant death syndrome (SIDS).
Acquired Long QT Syndrome
Long QT syndrome can be acquired through the use of specific medications. There are over 100 known medications that can prolong QT intervals. These medications belong to various classes, such as antibiotics, antidepressants, diuretics, antihistamines, and those used to regulate arrhythmias. In some cases, individuals who develop long QT syndrome as a result of medication may also have an underlying heart defect that increases their susceptibility to rhythm disturbances.