Heart Sounds (Lub-Dub):

• The normal heart sounds are described as “lub” and “dub.”
• Lub: Occurs during closure of the atrioventricular (AV) valves (mitral and tricuspid).
• Dub: Occurs during closure of the semilunar valves (aortic and pulmonary).
• Origin of the sounds: Not from the valves themselves, which are silent, but from the turbulence of blood flow as valves close.

Additional Heart Sounds:

• Sometimes hearing a third or fourth heart sound is normal, but more often they indicate abnormal blood flow.
• Murmurs: Abnormal or extra sounds caused by:
  • Incompetent valves: Valves that do not close properly, causing regurgitation, which produces a swooshing sound.
  • Septal defects: Holes in the septum (especially between ventricles) allow blood flow abnormally, creating additional sounds.

Pulse and Pulse Deficit

Pulse:

• Usually reflects the heart rate and strength of cardiac contractions.

Pulse Deficit:

• An abnormal condition where there’s a difference between the apical pulse (listening with a stethoscope over the heart) and the radial pulse (felt at the wrist).
• Common scenario:
  • Apical pulse: 60 beats per minute.
  • Radial pulse: 40 beats per minute.
• Implication:
  • The heart is beating, but the pressure wave is not reaching the periphery properly or strongly enough to be felt at the wrist.
  • Indicates issues like low stroke volume or weak cardiac contractions.

Causes of Pulse Deficit:

• Poor filling of the heart: Decreased preload or volume leading to less effective ejection.
• Weak contraction: Heart muscle weakness impairing ejection volume (stroke volume).

Why this is important:

It signals a cardiac problem, such as heart failure or arrhythmias affecting blood flow efficiency.

Summary:

Understanding heart sounds and pulse dynamics provides critical information on cardiac function. Normal heartbeats produce recognizable “lub-dub” sounds due to blood turbulence at valve closures. Abnormal sounds like murmurs can suggest valvular or septal defects. A pulse deficit indicates a mismatch between actual heart activity and peripheral blood flow, often pointing to low stroke volume or cardiac weakness.