NURSING ANM AND GNM

Detailed explanation-1: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.

Detailed explanation-2: -In a healthy heart, it takes approximately 30 msec for excitation to spread between the sinoatrial and atrioventricular nodes, and the widespread atrial activation occurs over a period of approximately 70 to 90 msec (Figures 2 and 3).