Laboratory data initially revealed mild acute kidney injury, and troponin-I 53 ng/mL, potassium was 3.2 mmol/L, magnesium 2.1 mg/dL, WBC 10.5 K/mcL and a normal drug screen. His EKG showed normal sinus rhythm with a PR interval of 198, QRS of 110 msec with what appeared to be an incomplete right bundle branch block and a corrected QT interval of 374 msec. There was no sign of acute ST-T elevation. Subsequently, his blood cultures turned positive for Salmonella enterica, subspecies 1. Given the cardiac arrest with an elevated troponin-I, he underwent extensive cardiac evaluation including a coronary angiogram which revealed no significant coronary artery disease and an echocardiogram that was reported to be normal except for mild increase in right ventricular size. For his diarrheal illness, he was initially started on broad spectrum antibiotics which were narrowed to intravenous ceftriaxone to treat Salmonella bacteremia. During his hospital stay, he was afebrile and did not suffer any further arrhythmias. Following discharge, he underwent genetic counselling followed by genetic testing for channelopathies revealing variants of uncertain significance for genes DES, DSP and SCN5A, none of which are directly linked to short QT syndrome. Given the ventricular fibrillation arrest and concern for short QT syndrome, he underwent insertion of an implantable cardiac defibrillator after completion of antibiotics.
Discussion: Nontyphoidal Salmonella bacteremia can cause myopericarditis which our patient likely had given the nature of his chest pain. However, it is unusual to cause a cardiac arrest in the absence of complications of the bacterial illness such as septic shock, cardiac tamponade or ventricular free wall rupture, none of which was present in our patient. It is therefore more likely that the presence of an acute febrile illness along with myocarditis precipitated the arrhythmia in the setting of a congenital short QT syndrome. Making a diagnosis of short QT syndrome is challenging, especially given the yield of genetic testing is only 20%. Using the diagnostic criteria proposed by Gollob et al, our patient scored 3 points (for cardiac arrest and a QT interval of less than 370 msec) placing him in the intermediate-probability for Short QT syndrome(Gollob).
Conclusions: Although rare, short QT syndrome can be lethal, especially in the face of an acute illness. Our patient suffered a cardiac arrest during the time of evaluation in an emergency room where expert care was immediately available.