​Differential diagnosis of long QT syndrome

​Differential diagnosis of long QT syndrome 
-hypothermia 
-stroke 
-subarachnoid hemorrhage 
-significant bradycardia
-myocardial ischemia 
-left ventricular hypertrophy 
-second degree AV block 
-third degree AV block 
-congenital long QT syndrome 
-prednisone 
-antibiotics such as  erythromycin, trimethoprim-sulfamethoxazole, levofloxacin, ketoconazole, itraconazole
-astemizole, terfenadine 
-tricyclic antidepressants
-class 1a anti arrhythmic ( quinidine, procainamide) 
-class 1c anti arrhythmic ( propafenone) 
-class III anti arrhythmic ( amiodarone, sotalol, bretylium) 
hypocalcemia 
-hypomagnesemia 
-hypokalemia