First Heart Sound

First Heart Sound

What are heart sounds? How are they produced? (or) First heart sound. 
Answer:

Heart sounds:

Heart sounds Definition:

• The mechanical activities of the heart during each cardiac cycle produce some sounds, called heart sounds.

“Understanding the first heart sound through FAQs: Mechanism, functions, and uses explained”

Types and their causes:

1. First heart sound:

• It is prominent.
• Resembles the word `LUBB’.
• Can be heard by stethoscope.
• Occurs during isometric ventricular contraction phase and part of ejection period of each cardiac cycle.
• Causes:
• Simultaneously close of A-V vales other factors include.

“Common challenges in mastering the first heart sound notes effectively: FAQs provided”

• • Valvular factors.
    1. Vibration created in the valvular leaflets and chordate tendinae.
  • Vascular factor.
    1. Blood flow into aorta and pulmonary artery during ejection period.
  • Muscular factor.
    1. Tension produced in myocardium and.
    2. Contraction of ventricular muscle.
  • Atrial factor.
    1. Vibrations set up due to atrial systole.
    2. Duration: 0.10-0.17 sec.

“Importance of studying the first heart sound for medical students: Questions explained”

2. Second heart sound:

• It is also prominent and heard by stethoscope.
• It resembles the word ‘DUBB’.
• Occurs during protodiastole and part of isometric ventricular relaxation of cardiac cycle.
  Causes:
• Synchronous and sudden closure of semilunar valves.
  Duration:
• 0.10 to 0.14 sec.

“Steps to explain the mechanism of the first heart sound: Mitral vs tricuspid valve closure: Q&A guide”

3. Third heart sound:

• It is very mild sound.
• Can be heard by microphone and not by stethoscope.
• It occurs during rapid filling phase of cardiac cycle.
  Causes:
• When there is sudden rush of blood into ventricles during rapid filling phase, vibrations are produced in the ventricular wall.
• These vibrations result in third heart sound
  Duration: 0.07, to 0.10 sec.

“Factors influencing success with the first heart sound studies: Q&A”

4. Fourth heart sound:

• It is an audible sound.
• Can be studied by phonocardiogram.
• It occurs during atrial systole.
• During atrial sysole, vibrations are produced in.
  1. Atrial musculature
  2. Flaps of atrioventricular valves.
  3. Some of ventricular myocardium.
• These vibrations results in fourth heart sound.
  Duration: 0.02-0.04 sec

Auscultation of S1 heart sound