Andersen–Tawil syndrome (LQT7)
LQT7, also known as Andersen–Tawil syndrome, is characterised by a triad of features – in addition to a prolonged QT interval, those affected may experience intermittent weakness often occurring at times when blood potassium concentrations are low (hypokalaemic periodic paralysis), and characteristic facial and skeletal abnormalities such as a small lower jaw (micrognathia), low set ears, and fused or abnormally angled fingers and toes (syndactyly and clinodactyly). The condition is inherited in an autosomal-dominant manner and is caused by mutations in the KCNJ2 gene which encodes the potassium channel protein Kir2.1. Timothy syndrome (LQT8)
LQT8, also known as Timothy syndrome combines a prolonged QT interval with fused fingers or toes (syndactyly). Abnormalities of the structure of the heart are commonly seen including ventricular septal defect, tetralogy of Fallot, and hypertrophic cardiomyopathy. The condition presents early in life and the average life expectancy is 2.5 years with death most commonly caused by ventricular arrhythmias. Many children with Timothy syndrome who survive longer than this have features of autism spectrum disorder. Timothy syndrome is caused by variants in the calcium channel Cav1.2 encoded by the gene CACNA1c. Table of associated genes
The following is a list of genes associated with Long QT syndrome:

Acquired
Although long QT syndrome is often a genetic condition, a prolonged QT interval associated with an increased risk of abnormal heart rhythms can also occur in people without a genetic abnormality, commonly due to a side effect of medications.
Unasyn is the trade name for two related antibiotic drugs:

Ampicillin/sulbactam, a fixed-dose combination medication of the penicillin antibiotic combination ampicillin/sulbactam
Sultamicillin, an oral form of the penicillin antibiotic combination ampicillin/sulbactam