A 44 year old man presented with recurrent symptomatic palpitations, always appearing during physical stress each with a similiar extent and never during resting periods. He also had fatigue and moderate dyspnoea during the episodes. The past medical history of the patient did not reveal any significant diseases. Findings of the attending physician including 12 lead ECG and echocardiography did not show any abnormality. As there was no electrocardiographic documentation of the episode, a 12-lead Holter evaluation was done
