A white woman in her 50s with a history of paroxysmal atrial fibrillation and a structurally normal heart, was prescribed flecainide, 100 mg twice a day, for rhythm control. She presented to the emergency department with complaints of experiencing palpitations for the past several hours. Her blood pressure on presentation was 138/86 mm Hg, and her heart rate was 205 beats per minute (bpm). A 12-lead electrocardiogram (ECG) was performed (Figure 1). She denied taking more than prescribed doses of flecainide. She was given intravenous bicarbonate and a second ECG was performed, (Figure 2).
Hegde S, Kumar V. Wide Complex Tachycardia in a Patient With a History of Atrial Fibrillation. JAMA Intern Med. 2016;176(3):386-388. doi:10.1001/jamainternmed.2015.7605