Cardiac Cycle and ECG Interpretation

Dr. Morton explains the cardiac cycle, detailing the phases of ventricular and atrial diastole and systole. The video covers isovolumetric relaxation and contraction, ventricular filling, and ejection. It also correlates these phases with ECG components like the P wave, QRS complex, and T wave, illustrating the electrical and mechanical events of the heart.

What does the cardiac cycle depict?

• Only the systolic phase

• The entire lifespan of the heart

• Only the diastolic phase

• One complete heartbeat

During which phase does ventricular filling occur?

• Atrial systole

• Ventricular diastole

• Ventricular systole

• Isovolumetric contraction

What happens during isovolumetric relaxation?

• Atria contract and blood fills the ventricles

• Ventricles relax but blood volume remains constant

• Ventricles contract and blood is ejected

• Blood flows from ventricles to atria

What is the role of the atrial kick?

• To push the last bolus of blood into the ventricles

• To close the AV valves

• To initiate ventricular contraction

• To open the semilunar valves

What marks the beginning of ventricular systole?

• Isovolumetric relaxation

• Ventricular ejection

• Atrial diastole

• Isovolumetric contraction

What occurs during ventricular ejection?

• Atria fill with blood

• Ventricles fill with blood

• Blood is ejected from the ventricles

• Blood is ejected from the atria

Which ECG component represents atrial depolarization?

• U wave

• QRS complex

• T wave

• P wave

What does the QRS complex indicate?

• Atrial repolarization

• Atrial depolarization

• Ventricular repolarization

• Ventricular depolarization

What does the T wave represent in an ECG?

• Ventricular depolarization

• Atrial depolarization

• Ventricular repolarization

• Atrial repolarization

How does the P wave relate to the cardiac cycle?

• It precedes ventricular contraction

• It follows atrial contraction

• It follows ventricular contraction

• It precedes atrial contraction