Our latest Emergency Department Minute Quiz from Brady Pregerson, MD. Can you determine the correct diagnosis?
History: A man in his 60s with a history of hypertension, GERD and diabetes on HCTZ, Prevacid and Invokana is brought to the emergency department for a witnessed seizure. He is now back to baseline and relates a 2 week history of vomiting, diarrhea, and anorexia. In the past few days he had also developed generalized weakness and intermittent tingling in his hands and feet. He states he may have blacked out yesterday; he woke up lying on the couch with a headache that went away, but wrote it off at the time to just dozing off. He denies any palpitations, chest pain, SOB, fever abdominal pain or other complaints. Glucose in the field was 162
Exam: Vital signs are normal except for a pulse of 49 and a blood pressure of 88/51. Temperature and pulse ox are normal. Exam is notable for slightly dry mucous membranes and bradycardia but is otherwise normal including a neurologic exam.
COMPUTER EKG READ:
Marked sinus bradycardia with sinus arrhythmia (HR = 46)
Prolonged QT (QTc = 600ms)
What is the most likely diagnosis?