Answer: A brief backflow of blood against the closed aortic valve during early diastole.
- A A brief backflow of blood against the closed aortic valve during early diastole
- B Atrial contraction occurring just before ventricular systole in the majority of documented cases
- C The peak of ventricular systolic pressure during ejection according to most studies
- D Opening of the atrioventricular valves at the start of diastole under usual circumstances
Correct answer: A. A brief backflow of blood against the closed aortic valve during early diastole
Explanation: The dicrotic notch is a small dip and rebound in the arterial pressure trace, caused by elastic recoil of the aortic wall and brief backflow of blood against the recently closed aortic valve.
A single ECG cycle: the P wave marks atrial depolarisation (contraction signal), the large QRS complex marks ventricular depolarisation, and the T wave marks ventricular repolarisation (recovery) before the next cycle begins.
Concept context
Blood, lymph, the heart, the cardiac cycle, blood pressure, and ECG. High NEET weightage.