Long QT syndrome is associated with lethal tachyarrhythmia that can lead to syncope, seizure, and sudden death. Congenital long QT syndrome is a genetic disorder, characterized by delayed cardiac repolarization and prolongation of the QT interval on the electrocardiogram (ECG). Type 2 congenital long QT is linked to mutations in the human ether a go-go-related gene (HERG). There are environmental triggers of adverse cardiac events such as emotional and acoustic stimuli, but fever can also be a potential trigger of life-threatening arrhythmias in long QT syndrome type 2 patients. Herein, we report a healthy young man who experienced fever-induced polymorphic ventricular tachycardia and QT interval prolongation.
Adult ; Electrocardiography ; Fever/*complications ; Humans ; Long QT Syndrome/*diagnosis/*etiology ; Male ; Ventricular Fibrillation/*diagnosis/*etiology

Prolongation of QTc interval associated with Takotsubo cardiomyopathy (TC) has previously been reported in published case series. We report an unusual case of a patient who presented with TC associated with long-QT syndrome and developed cardiac arrest secondary to torsade de pointes. Since QT prolongation and bradycardia persisted after the resolution of TC, the patient received permanent pacemaker. Since then additional event did not occur. QT prolongation and bradycardia could be persistent even after recovery of TC, and permanent pacemaker insertion may be a treatment option of long QT syndrome related with TC.
Aged ; Bradycardia/diagnosis/therapy ; Cardiac Pacing, Artificial ; Coronary Angiography ; Diagnosis, Differential ; Electrocardiography ; Female ; Heart Arrest/diagnosis/etiology ; Humans ; Long QT Syndrome/*diagnosis/etiology ; Takotsubo Cardiomyopathy/complications/*diagnosis/ultrasonography ; Torsades de Pointes/*diagnosis/etiology

OBJECTIVETo explore the predictive value of QT interval dynamicity for sudden death in patients with idiopathic dilated cardiomyopathy (DCM).

METHODSFifty-five patients with DCM (DCM group) and 27 healthy subjects (Control group, Con) were enrolled. Investigations included history collection, clinical examination, echocardiography, electrocardiogram and 24 h ambulatory electrocardiogram. Following indexes were determined: left ventricle end diastolic dimension (LVEDD), left ventricle ejection fraction (LVEF), QT dispersion (QTd), SDNN, the slope of QT/RR plots of the linear regression, ventricular premature beats (VPB) and non-sustained ventricular tachycardia (NSVT). Primary end point for patients with DCM was all cause death.

RESULTSLVEDD, QTd, VPB/24 h, NSVT/24 h, QTe/RR slope and QTp/RR slope were significantly higher while LVEF and SDNN were significantly lower in DCM group than in Con group (all P < 0.05). LVEDD, LVEF, QTd, SDNN, QTe/RR slope and QTp/RR slope were significantly different among DCM sudden death group, DCM non sudden death group and Con group (P < 0.05). LVEF, SDNN, QTe/RR slope and QTp/RR slope were significantly different between DCM sudden death and non sudden death group (P < 0.05). LVEF, QTd, VPB/24 h, QTe/RR slope and QTp/RR slope were significantly different between DCM with NSVT and DCM without NSVT group (P < 0.05). The sudden death rate of DCM patients with QTe/RR slope ≥ 0.210 was significantly higher than DCM patients with QTe/RR slope < 0.210 (54.5% vs. 21.1%, P < 0.05). Sudden death rate of QTp/RR slope ≥ 0.190 was also higher than those < 0.190 (52.2% vs. 21.9%, P < 0.05). The sudden death rate of DCM patients with both LVEF ≤ 35% and NSVT+ was 62.5%. Combining QTe/RR ≥ 0.210 with NSVT+ or LVEF ≤ 35%, the sudden death rates were 62.5% or 66.7%. Combining QTp/RR ≥ 0.190 with NSVT+ or LVEF ≤ 35%, the sudden death rates were 66.7% or 61.5%. Combining QTe/RR ≥ 0.210 or QTp/RR ≥ 0.190 with NVST+ and LVEF ≤ 35%, the sudden death rates were 77.8% or 70.0%.

CONCLUSIONSHigh QT/RR slope is a risk factor for sudden death of DCM patients. QT/RR slope is a useful predictor for sudden death in DCM patients either independently or combined with NSVT or LVEF.

Adult ; Aged ; Aged, 80 and over ; Cardiomyopathy, Dilated ; complications ; diagnosis ; physiopathology ; Case-Control Studies ; Death, Sudden, Cardiac ; etiology ; Electrocardiography, Ambulatory ; Female ; Heart Rate ; Humans ; Long QT Syndrome ; complications ; diagnosis ; Male ; Middle Aged ; Predictive Value of Tests ; Prognosis ; Risk Factors

Arrhythmias, Cardiac ; diagnosis ; genetics ; pathology ; Brugada Syndrome ; diagnosis ; genetics ; pathology ; Channelopathies ; diagnosis ; genetics ; pathology ; DNA Mutational Analysis ; Electrocardiography ; Genetic Testing ; Heart Conduction System ; physiopathology ; Humans ; Infant ; Long QT Syndrome ; diagnosis ; genetics ; pathology ; Muscle Proteins ; genetics ; Mutation ; NAV1.5 Voltage-Gated Sodium Channel ; genetics ; Sodium Channels ; genetics ; Sudden Infant Death ; etiology

Timothy syndrome, long QT syndrome type 8, is highly malignant with ventricular tachyarrhythmia. A 30-month-old boy had sudden cardiac arrest during anesthesia induction before plastic surgery for bilateral cutaneous syndactyly. After successful resuscitation, prolonged QT interval (QTc, 0.58-0.60 sec) and T-wave alternans were found in his electrocardiogram. Starting beta-blocker to prevent further tachycardia and collapse event, then there were no more arrhythmic events. The genes KCNQ1, KCNH2, KCNE1 and 2, and SCN5A were negative for long QT syndrome. The mutation p.Gly406Arg was confirmed in CACNA1C, which maintains L-type calcium channel depolarization in the heart and other systems.
Anesthesia/*adverse effects ; Calcium Channels, L-Type/*genetics ; Death, Sudden, Cardiac/*etiology ; Electroencephalography ; Humans ; Infant ; Long QT Syndrome/*genetics ; Magnetic Resonance Imaging ; Male ; Methyl Ethers/adverse effects ; Nitric Oxide/adverse effects ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA ; Surgery, Plastic ; Syndactyly/diagnosis/*genetics/surgery