A 34-year-old man presented to the emergency department complaining of weakness and shortness of breath over two weeks. He described a generalized weakness, progressively worsening over the previous few days.
The patient's dyspnea had progressed from exertion to rest over the same time. He also complained of lightheadedness, nausea, and occasional vomiting, but denied chest pain, palpitations, or abdominal pain.
The patient admitted to a recent methamphetamine use, but denied prior cardiac history, hospitalizations, or surgery. On exam, vitals signs were notable for a pulse of 152 bpm, blood pressure of 142/68 mm Hg, and respiratory rate of 24 bpm. Pulse oximetry was 95% on room air.
The patient was in moderate distress, chest was clear to auscultation, cardiac exam was notable for a regular tachycardia with a 2/6 systolic murmur, abdomen was soft and nontender, and neurologic exam was notable for mild diffuse weakness symmetrically.
An ECG was obtained (Figure 1). Initial treatment included oxygen, IV fluids, and lidocaine without change. After an arterial blood gas revealed a significant metabolic acidosis (7.08/217/22), sodium bicarbonate was administered. A repeat ECG was obtained 15 minutes later (Figure 2). What is your diagnosis and course of treatment? See p. 8.