A 28 year old white woman was admitted after transient loss of consciousness. She remembered repeatedly lifting her neighbour’s child and finding herself on the floor the next moment. She had no nausea, sweating, or blurred vision before or after the event. Her husband confirmed that she had suddenly stopped in her movement, fallen down, and fully recovered within moments. She had never experienced such an episode before. However, she had experienced chest pain during physical exertion in the past three months. She had no previous medical history, an unremarkable family history, and was not taking medication.

On physical examination she was alert and oriented, with a heart rate of 70 beats/min and a blood pressure of 130/80 mm Hg. She had no signs of a tongue bite, injury, or incontinence. On auscultation, she had a midsystolic murmur over the right second intercostal space, with radiation into both carotid arteries. Electrocardiography showed a sinus rhythm with biphasic T-waves in III and aVF. Full blood count, electrolytes, glucose, renal function, liver function, and C reactive protein were normal. Her erythrocyte sedimentation rate was 22 mm/h (normal <11 mm/h).