A 38-year-old female secretary suddenly felt weak and lightheaded while eating lunch. She noticed that her heart pounded rapidly and regularly with no neck pulsation or previous history of palpitation:

• Supraventricular tachycardia (AVNRT, AV Nodal Re-entrant Tachycardia)
• Non specific ST abnormality

The arrhythmia and the associated symptoms subsided with carotid sinus massage. The patient was referred to her family physician.