Which of the following concerning the electrocardiogram (ECG) is/are correct? l A. The P-wave is caused by repolarizatio

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Which of the following concerning the electrocardiogram (ECG) is/are correct? l
A. The P-wave is caused by repolarization of the atrioventricular (AV) valves
B. The QRS complex occurs at the beginning of Phase 2(isovolumetric
ventricular contraction phase) of the cardiac cycle
C. Depolarization of the atrial muscle causes the T –wave
D. The repolarization of the atrial muscle cannot be seen on a typical ECG
because it is obscured by the T wave
E. Both A and B are correct