Torsade De Pointes
...that presented to the ER with ventricular tachycardia, of which elevated to ventricular fibrillation and was unsuccessfully resuscitated. Furthermore, what genetic presupposition to development of VT did she have, and how was this augmented by the influence of Seldane ® (active ingredient terfenadine), an over the counter anti-histamine allergy season remedy.
Clinical History
During spring time of 1998, a typically healthy 43 year old deaf woman presented in the ER with cardiac arrhythmia. Electrocardiogram (ECG) analysis showed a broad QRS segment, suggesting sustained ventricular tachycardia (VT). Due to the ECG analysis, chemical cardioconversion by lidocaine administration was attempted (a 100 mg IV was rapidly run for 2 minutes as standard initial procedure); however, rapid onset of ventricular fibrillation occurred. Direct current defibrillation was employed with a range of 200-300 joules, but unfortunately was unsuccessful. Before a second attempt of defibrillation could be administered, the woman presented with syncope. CPR was attempted however was unsuccessful; briefly after was pronounced dead due to sudden cardiac death (SCD).
Investigations
Blood samples showed sodium (Na+), potassium (K+), and calcium (Ca2+) imbalances, and high content of over the counter antihistamine active ingredient terfenadine. After overview of the patient's medical history, it was confirmed that her deafness was of congenital nature (specifically neurosensorial). Understanding that this feature is often linked to congenital long QT syndromes, genetic analysis was performed. Analysis found a point mutation in the KCNQ1 and KCNE1 genes (found on chromosome 11), of which she was homozygous recessive.
Discussion: Clinico-pathological Correlations
The genetic findings on chromosome 11 specifically regarding genes KCNQ1 and KCNE1 definitively confirm that the...
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