Bidirectional Ventricular Tachycardia in a Young Female: A Case of Andersen-Tawil Syndrome.

Bidirectional ventricular tachycardia (VT) is a rare ventricular dysrhythmia with a limited differential diagnosis that includes digitalis toxicity, catecholaminergic polymorphic VT, aconite poisoning, and genetic channelopathy syndromes, specifically, Andersen-Tawil syndrome (ATS). We present a case of a young female with palpitations found to have bidirectional VT on cardiac event monitor and strong family history of cardiac dysrhythmias. Her physical examination findings included minor dysmorphic features of mandibular hypoplasia, hypertelorism, and clinodactyly. The patient was clinically diagnosed with ATS and started on a beta-blocker for control of ectopy. A second Holter review demonstrated markedly decreased burden of ventricular ectopy compared to the initial monitoring. She was referred for genetic testing, which revealed a KCNJ2 mutation. Bidirectional VT is an uncommon ventricular dysrhythmia that has a limited differential diagnosis, one of which is ATS-a rare genetic disorder that results from mutations in the KCNJ2 gene. The condition is frequently associated with developmental, skeletal, and cardiac abnormalities. Although there are no strong recommendations that exist for treatment of ventricular dysrhythmias associated with this genetic disorder, we demonstrate a case of clinical improvement in a patient with ATS by using the beta-blocker metoprolol succinate. Furthermore, we propose that ATS patients may not need exercise restrictions as overall ventricular ectopy burden decreased with exercise and there was no prolongation of the QT interval. This patient will continue to follow up in our clinic to reassess symptom burden and for continued monitoring for the development of any new features.

Genetic polymorphisms and plasma levels of transforming growth factor-beta(1) in Chinese patients with tuberculosis in Hong Kong.

Susceptibility to tuberculosis (TB) may be affected by host genetic factors. Elevated levels of transforming growth factor-beta 1 (TGF-beta(1)) were found in plasma of patients with active TB compared with those of healthy contacts. To investigate the association of TGF-beta(1) gene polymorphisms (C-509T and T869C) and plasma levels with the risk of TB in Hong Kong Chinese adults, a case-control study was carried out on 174 active TB patients and 174 healthy controls matched for age, gender and smoking. Blood samples from 180 blood donors served as another control group. Genotyping was carried out on genomic DNA using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Plasma TGF-beta(1) was measured by commercially available ELISA kit. We found no differences in the distribution of genotypes or alleles of TGF-beta(1) gene polymorphisms at C-509T and T869C between patients and either group of healthy controls. Patients with TB had elevated plasma TGF-beta(1) levels compared with healthy controls irrespective of their genotypes (p<0.001). In conclusion, TGF-beta(1) gene polymorphism at C-509T and T869C is not associated with TB susceptibility in Hong Kong Chinese adults, but elevated plasma TGF-beta(1) levels suggests that this cytokine may play a role in the pathogenesis of tuberculosis.