Tachycardia Caused by a Concealed Accessory Pathway

Tachycardia caused by a concealed accessory pathway. Tachycardia rate is 240/min, and the QRS complex is narrow. Because there is no antegrade conduction from the atrium towards the ventricle, no delta wave is seen in resting ECG and the accessory pathway is not dangerous as in WPW syndrome.

Picture: Duodecim Medical Publications Ltd