What is S1 S2 (first and second heart sounds) Gallup?

S1 S2 Gallop: Understanding Heart Sound Abnormalities

S1 S2 gallop refers to the presence of both first (S1) and second (S2) heart sounds along with an additional abnormal heart sound (gallop), which can be either an S3 or S4 sound, indicating potential cardiac dysfunction.

Normal Heart Sounds (S1 and S2)

S1 (First Heart Sound)

• Produced by closure of the mitral and tricuspid valves
• Normally louder at the apex of the heart
• Has a "lub" quality during auscultation
• Timing coincides with the beginning of ventricular systole

S2 (Second Heart Sound)

• Produced by closure of the aortic and pulmonic valves
• Normally louder at the base of the heart
• Has a "dub" quality during auscultation
• Timing coincides with the end of ventricular systole
• Physiologically splits during inspiration and narrows or disappears during expiration 1

Gallop Sounds (S3 and S4)

S3 (Ventricular Gallop)

• Occurs early in diastole, after S2
• Low-pitched sound best heard with the bell of the stethoscope
• Indicates ventricular dysfunction and cardiac decompensation
• Common in heart failure, volume overload states
• Creates a "lub-dub-duh" rhythm (like the word "Ken-tuc-ky")
• Can be eliminated with pressure on the stethoscope 2

S4 (Atrial Gallop)

• Occurs late in diastole, just before S1
• Low-pitched sound best heard with the bell of the stethoscope
• Indicates decreased ventricular compliance
• Common in coronary heart disease and hypertension
• Creates a "duh-lub-dub" rhythm (like the word "Ten-nes-see")
• Not eliminated with pressure on the stethoscope, unlike S3 2

Clinical Significance of Gallop Sounds

S3 Gallop

• Pathognomonic for heart failure when occurring in adults over 40 years
• May be normal in children, young adults, and pregnant women
• Indicates volume overload and decreased ventricular compliance
• Requires prompt clinical attention in appropriate clinical context

S4 Gallop

• Indicates increased resistance to ventricular filling
• Common in:
  • Coronary artery disease
  • Hypertensive heart disease
  • Left ventricular hypertrophy
  • Aortic stenosis
• Does not necessarily indicate heart failure (unlike S3) 2

Summation Gallop

• When both S3 and S4 gallops occur simultaneously
• Results in a single, loud sound that may be louder than S1 or S2
• Typically occurs during tachycardia when diastole shortens
• Can be misinterpreted as a valvular or congenital lesion 2

Auscultation Technique for Detecting Gallops

• Use the bell of the stethoscope (better for low-frequency sounds)
• Have patient in left lateral decubitus position
• Listen at the apex for S3 and S4
• For patients with emphysematous chest, listen over xiphoid or epigastric area 2
• Use the "inching" technique: keep S2 as reference and move stethoscope from aortic area to apex to accurately time extra sounds 2

Diagnostic Evaluation

• Echocardiography is essential for confirming underlying causes 1
• Assess for:
  • Ventricular function and chamber size
  • Valve morphology and function
  • Congenital anomalies
  • Pericardial effusion
• Electrocardiogram to identify conduction abnormalities and chamber enlargement patterns 1

Clinical Pearls

• S3 gallop indicates cardiac decompensation and is a key clinical finding in heart failure
• S4 gallop is a constant finding in patients with hypertension but does not necessarily indicate heart failure
• Both S3 and S4 gallops may be present in patients with cardiac decompensation associated with coronary heart disease, hypertensive heart disease, and dilated cardiomyopathy 2
• The presence of a gallop sound significantly increases the likelihood of cardiac dysfunction and should prompt further evaluation

Remember that accurate auscultation and identification of gallop sounds are valuable clinical skills that can provide immediate diagnostic information about a patient's cardiac status.