A man in his 70s with history of atrial flutter (AFL) treated with metoprolol succinate (and not prescribed an anticoagulation drug), heart failure with preserved ejection fraction, hypertension, and type 2 diabetes presented with intermittent palpitations and dyspnea. These episodes were most consistently triggered by anxiety and had been occurring daily for 1 month. On the morning of admission, the patient experienced another one of these episodes but his heart rate remained persistently elevated, so he presented to the emergency department. He was found to be afebrile with heart rate of 136 beats per minute (bpm) and blood pressure of 147/96 mm Hg. Cardiac and pulmonary examination results were positive for tachycardia and faint bibasilar crackles. An electrocardiogram (ECG) showed typical AFL with 2:1 conduction, so the patient was given boluses of metoprolol and started on an intravenous amiodarone hydrochloride infusion as well as enoxaparin sodium. The patient’s heart rate decreased to 126 bpm, albeit still with 2:1 conduction (Figure A). Later that night his blood pressure fell to the range of 70/30 to 79/39 mm Hg. The ECG is shown in the Figure, B.
Douglas J. Hall, Timothy W. Smith, Amit Noheria. Wide Complex Tachycardia in a Patient Without Conduction System Disease. JAMA Intern Med. Published online November 27, 2017. doi:10.1001/jamainternmed.2017.6569