AH interval on ECG is for conduction ?
Through His-Purkinje system
From AV node to bundle of His
From Purkinje system to ventricular fibres
Through ventricular fibers
Ans. is 'b' i.e., From AV node to bundle of His Ceain intervals are measured to provide information regarding AV block. i) PA interval : It is time taken from onset of P-wave to onset of deflection in atrial catheter. It is an index of intra-atrial conduction. Normal vlaue is less than 55 mS. ii) AH interval : it represents conduction through AV node, i.e., conduction from AV node to bundle of His. Normal vlaue is less than 130 mS. iii) HV interval : It represents conduction through His-Purkinje system, i.e., conduction from His-Purkinje system to ventricular muscle fibers. Normal value is less than 50 mS.