A person's electrocardiogram (ECG) has no P wave, but has a normal QRS complex and a normal T wave. Therefore, his pacemaker is located in the: (a) sinoatrial (SA) node (B) atrioventricular (AV) node (C) bundle of His (d) Purkinje system (e) ventricular muscle
*The P wave represents the wave of depolarization that spreads from the SA node throughout the atria. *The QRS complex represents ventricular depolarization. *The T wave represents ventricular repolarization.