Thiamine deficiency is commonly associated with malnutrition, alcoholism and bariatric surgery. Thiamine deficiency can manifest in different ways, especially in developing countries: as peripheric neuropathy, as Wernicke encephalopathy or as beriberi disease. The authors present the case of a 72-year-old male, with a hiatal hernia that led to thiamine deficiency due to malnutrition. The initial clinical manifestation was an ST-elevation myocardial infarct equivalent, an ECG with a shark-fin pattern that evolved to a Wellens type B pattern. The patient evolved with severe altered mental status. A Wernicke encephalopathy diagnosis was confirmed by MRI; the patient was medicated with high-dose thiamine, with quick recovery, both neurologic and cardiac. The clinical history and response to treatment confirm the diagnosis of Wernicke encephalopathy and beriberi disease.