What is observed on the EKG when the ventricular myocardium depolarizes?

What is observed on the EKG when the ventricular myocardium depolarizes?

• A. A P wave
• B. A T wave
• C. A QRS complex
• D. A flat line

Answer: (C)

When the ventricular myocardium depolarizes, the QRS complex is observed on the EKG. This complex represents the rapid depolarization of the ventricles, which occurs as a part of the cardiac cycle. During this phase, electrical impulses travel through the bundle of His and branches, causing the ventricles to contract and pump blood to the lungs and body.

The shape of the QRS complex is characterized by a steep upward deflection followed by a downward deflection. It is typically narrow in width in healthy individuals, and its presence indicates that the electrical activity is effectively spreading through the ventricular muscle tissue.

The other options refer to different aspects of the cardiac electrical cycle. The P wave represents atrial depolarization, occurring before the QRS complex, while the T wave represents ventricular repolarization, occurring after depolarization. A flat line does not represent any electrical activity and would indicate a state of asystole or lack of heart activity.