An asymptomatic 5-year-old girl presented with bradycardia during a routine well-child visit. Further evaluation revealed profound sinus bradycardia, exercise-induced bidirectional ventricular tachycardia, and supraventricular tachycardia. An echocardiogram showed heavy trabeculations in the left ventricular myocardium. This patient's presentation suggested catecholaminergic polymorphic ventric...

The intrinsic heart rate (IHR) was determined in 17 patients with symptomatic sinus bradycardia by administering atropine 0.04 mg/kg and propranolol 0.2 mg/kg, i.v. In this way, sick sinus (SSS) patients with intrinsic sinus node (SN) dysfunction could be distinguished from those patients with disturbed autonomic regulation of SN function. Sick sinus syndrome patients with normal corrected sinu...

We present a case of sinus node arrest leading to symptomatic junctional bradycardia from oral phenytoin toxicity, which is a rare presentation. Our patient had no prior cardiac history and was on phenytoin therapy for seizure disorder. Although bradycardia is more commonly associated with intravenous phenytoin and there were few case reports of bradycardia with oral phenytoin reported, the lit...