Hayden is a 13-year-old boy who, accompanied by his concerned mother, presents to your practice after collapsing unconscious while playing soccer. He recovered quickly and felt ne, so his coach had not called an ambulance. Hayden remembers drinking plenty of water before the game. Hayden has no known medical problems and is fully immunised. He denies any episodes of feeling dizzy, but has felt his heart beat forcefully at times. As Hayden is unsure of the duration of these episodes, you ask him to tap on your desk to provide an example. He taps at a rate of well over 100 beats per minute for a period of 15 to 20 seconds. Importantly, Hayden does not consume any caffeine or energy drinks. You ask about any sudden deaths in the family, and his mother reports that her brother died unexpectedly at 34 years of age. She recalls the autopsy was ‘normal’, however you acknowledge that routine genetic testing was not yet available at that time.
What does the clinical examination show? Hayden looks comfortable at rest. He is 156 cm tall, weighs 52.5 kg and has a body mass index of 21.3 kg/m2, which is within the normal range. His heart rate is 67 beats per minute and regular, and his blood pressure is 110/70 mmHg. He is afebrile with a temperature of 36.8 ̊C. Hayden’s peripheries are warm and pulses are equal at radial and femoral arter- ies. He has no conjunctival pallor. His carotid arteries have no bruits, his heart sounds are dual with subtle splitting of the second heart sound on inspiration, which resolves with expiration. is is a normal nding in a young person. His lung elds are clear to auscultation. His abdomen is so and non- tender, and there is no organomegaly. His blood sugar level is normal.