The correct route through which impulse travel in the heart is 

In the human heart, the sequence in which the action potential travels is; 

SA node$\to$AV node$\to$Bundle of His$\to$Purkinje fibres$\to$Ventricular muscles

A patch of nodal tissue is present in the right upper corner of the right atrium called the sino-atrial node (SAN). Another mass of this tissue is seen in the lower left corner of the right atrium close to the atrio-ventricular septum called the atrio-ventricular node (AVN). A bundle of nodal fibres, atrioventricular bundle (AV bundle) continues from the AVN which passes through the atrio-ventricular septa to emerge on the top of the interventricular septum and immediately divides into a right and left bundle. These branches give rise to minute fibres throughout the ventricular musculature of the respective sides and are called Purkinje fibres.