長QT症候群(Long QT syndrome)──病例報告

A Case of Long QT Syndrome

家庭成員的猝死是造成其它成員情緒崩潰的原因，它常是因為基因造成的心律不整所引起，這些心律不整以長QT症候群(Long QT syndrome)最為常見，它的特徵是在心電圖看到QT間隔的過度延長（男性大於440毫秒，女性大於460毫秒），造成多型性的心室心律不整(polymorphic ventricular arrhythmia,Torsades de pointes)，心室顫動(ventricular fibrillation)這是一位44歲的男性，有高血壓、肥厚性心臟心室疾病(HCVD)，第二型糖尿病(Type II DM)，因末期腎臟疾病而眼盲，並接受洗腎，一星期前有發生過暈厥和心室性心搏過速，因持續間歇性的胸悶喘不過氣而來醫院求診醫師發現病人有以下症狀：1.有症狀的心搏過緩、2.左下肺葉肺炎、3.右側肋膜積水，病人被收入加護病房並置入經靜脈的心律調節器做更嚴密的監測，之後不久監測器發現QT間隔的過度延長，在沒有電解質不平衡的情況下好幾次的的心室心律不整Torsades depointes)，心室顫動，我們先用經靜脈的抗心律不整藥物加以治療，並加上口服的Mexilitine和Xanthium，病人的症狀得到良好的控制，病人因為又有肺炎以及感染因靜脈導管所引起對Oxacillin有抗藥性的金黃色葡萄球菌，使得病情更加複雜，我們用靜脈注射vancomycin和ceftazidime加以治療，病情穏定後後我們放置了VVIR。心律調節器和口服藥物後讓病人出院，之後的基因序列檢查發現這個病人所患的是先天性的第二型長QT症候群。

Sudden death of a family member is an emotionally devastating event and unfortunately an all-too-common presentation of genetic arrhythmia syndromes. The most common of these syndromes is the long-QT syndrome, which is characterized by an abnormal QT-interval prolongation on the surface ECG (>440 msec in men, >460 msec in women) and an increased risk of sudden death, usually due to polymorphic ventricular arrythmia (Torsades de pointes) leading to ventricular fibrillation. A 44 year old man with hypertension, HCVD, Type 2 DM, legal blindness with ESRD on regular HD, and a recent history of syncope and VT during the previous week, presented to our Taichung Cheng Ching Hospital for persistent intermittent chest tightness and shortness of breath. He was found to have symptomatic bradycardia (HR 40-50),left lower lobe pneumonia, and right sided pleural effusion. He was admitted to MICU for close monitoring. Initially, a transvenous pacemaker was placed due to persistent bradycardia. Telemetric monitoring showed prolonged QT (QTc 536 msec), recurrent runs of Torsades and ventricular fibrillation in the absence of electrolyte imbalance. He was also treated with antiarrythmic agents intravenously, followed by mexiletine and Xanthium orally, and his symptoms were controlled. The hospital course was complicated by hospital-acquired pneumonia and ORSA bacteremia from catheter -related infections and he was treated with vancomycin and ceftazidime intravenously. He was discharged home after VVIR pacemaker placement on oral medications. On further testing, he was found to have late onset congenital LQTS type 2 proven by DNA sequence testing.