Cardioversion

Case Synopsis

An 88-year-old woman with a background of hypertension, angina, and mild asthma presented to the emergency department (ED) with a 10-day history of abdominal pain, nausea and vomiting, and reduced oral intake. She was initially being treated for acute dehydration secondary to gastroenteritis. On further questioning, she had a significant history of ischemic heart disease (IHD) limiting exercise tolerance, having suffered from a previous myocardial infarction in the right coronary territory, for which she underwent emergency (primary) percutaneous coronary intervention. On examination, the airway was patent, respiratory rate was labored at 30 breaths per minute, arterial saturations were 92% on 5 L of oxygen via facial mask, heart rate (HR) was irregularly irregular at 137 beats per minute, and blood pressure (BP) was 94/45 mm Hg. The laboratory results demonstrated a serum potassium of 3.1 mEq/L, blood urea nitrogen 33 mg/dL, creatinine 310 mmol/L, magnesium 0.57 mmol/L, and phosphate 0.38 mmol/L. The 12-lead electrocardiogram (ECG) showed new-onset atrial fibrillation (AF) with a rapid ventricular response, and Q waves and ST depression in leads 2, 3, and aVF. Following initial resuscitation, she was found to have a small bowel obstruction on abdominal computed tomography and was booked for urgent surgical intervention. Her HR was now 160 beats per minute and her BP was 60/35 mm Hg despite fluid therapy. To facilitate emergent direct current (DC) cardioversion within the ED, the anesthesiologist induced general anesthesia, and the patient was successfully cardioverted to sinus rhythm (SR) after the third shock at 150 J. Invasive monitoring was then instituted, and she was transferred to the operating room for urgent surgical intervention.