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Basics of cardiac auscultation

Auscultation is the most important part in cardiovascular examination. Doctor should gain the skill by experience obtained by constant repetition. Diagnosis of heart disease especially congenital and valvular heart disease, were done on the auscultatory finding before the advent of echocardiography.

Stethoscope was invented by Rene-Theophile-Hyacinthe Laennec.
Features of ideal stethoscope
  • Ideal stethoscope should have tube length of 25 cm
  • Double tube is better, the size of the tube - 0.3 cm, 
  • Two chest pieces diaphragm with a diameter of 4 cm, bell with a diameter of 2.5 cm, and well fitting ear pieces. 
  • Bell is used to hear low pitched sounds and murmurs (30 to 150 Hz), you should not press the bell too much since the skin will act as a diaphragm.
  • Low pitched sounds and murmurs
  • Third heart sound
  • Fourth heart sound
  • Mid diastolic murmurs.
Diaphragm of stethoscope is used for high pitched sounds and murmurs, this will filter out low pitched sounds of less than 300 Hz.
  • High pitched sounds and murmurs
  • First heart sound .
  • Second heart sound
  • Opening snaps
  • Tumour plops
  • Pericardial rubs, knocks
  • Systolic murmurs
  • Early diastolic murmurs.
  • Clicks
The beginner will have difficulty in identifying the auscultatory findings. you should understand the physiological events in cardiac cycle,first identify the 1st and 2nd heart sounds for differentiating the systolic and diastolic phase and events occurring there in. Remembering the quality of sounds and murmurs is the easy method for the recognition of the findings, than the other features in description