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Diastolic sounds - mid to late

Third heart sound is mid-diastolic

• Listen with the bell
• Near the apical impulse for left ventricular sounds.
• Near the lower left sternal edge for right ventricular sounds.
• Lower in pitch than the first heart sound.
• Common in childhood, but should not be heard after the age of 40.
• Occurs at the end of rapid ventricular filling.
• Occurs in some patients with dilated right or left ventricles.
• Intensity of right-sided S3 increases with inspiration.

Fourth heart sound occurs in late diastole

• Uncommon in normal individuals younger than age 50
• Occurs after atrial contraction.
• Often reflects reduced left ventricular compliance.

Summation gallop

• Occurs with long PR interval or increased heart rates.
• Due to superimposition of S3 and S4.