Heart murmurs

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Extra (gallop) heart sounds

Tip

• S3: volume-overloaded
  • Three tree → tree is big and large → ventricle is large
• S4: pressure-overloaded
  • Four door → door is hard → ventricle is stiff

S3

• Features
  • Heard just after S2 (after opening of mitral valve)
  • Caused by reverberant sound as blood fills an enlarged LV cavity during passive diastolic filling (i.e. end systolic volume is high)
• Associated disorders
  • Heart failure with reduced EF
  • High-output states (eg, thyrotoxicosis)
  • Mitral or aortic regurgitation
  • Teens or athletes
    • Hearts are trained to handle more blood

S4

• Features
  • Heard just before S1 (before closing of mitral valve)
  • Caused by blood striking a stiff LV wall during atrial contraction
    • As the atria contracts in late diastole against a stiffened ventricle, it must increase its force-production, which creates turbulent blood flow.
• Associated disorders
  • Concentric LV hypertrophy
  • Restrictive cardiomyopathy
  • Acute myocardial infarction

Jugular venous pressure

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Cardiovascular examination

Wave	Description	Abnormalities
a wave	The first peak caused by atrial contraction	Absent in atrial fibrillation
c wave	The second peak caused by tricuspid valve closure, contraction of the right ventricle, and bulging of the tricuspid valve into the right atrium	cv wave : severe tricuspid valve regurgitation
x descent	A drop in JVP caused by atrial relaxation	Absent in:
		Tricuspid valve regurgitation
		Right heart failure
v wave	The third peak caused by venous refilling of the right atrium against the closed tricuspid valve	Prominent in:
		Tricuspid valve regurgitation
		Right heart failure
y descent	A drop in JVP caused by decreased right atrial pressure as blood flows into the right ventricle after opening of the tricuspid valve	Prominent in: [7]
		Tricuspid valve regurgitation
		Constrictive pericarditis
		Absent in:
		Cardiac tamponade
		Tricuspid valve stenosis

Pathology

Common abnormalities of the JVP waveform include:

• Constrictive pericarditis: elevated JVP (due to increased external atrial pressure) with a prominent x (exaggerated atrial relaxation) and y (early rapid ventricular filling) descent
• Cardiac tamponade: elevated JVP (due to increased external atrial pressure), a prominent x descent (exaggerated atrial relaxation), and a blunt or absent y descent (minimal ventricular filling)
• Tricuspid regurgitation: prominent v wave as the blood from the right ventricle regurgitates into the right atrium during ventricular systole (atrial diastole), increasing interatrial pressure and volume
• Tricuspid stenosis: giant a wave due to high right atrial systolic pressure
• Atrial septal defect: v wave ≥ a wave due to the left-to-right shunting of blood
• Third-degree atrioventricular (AV) block: cannon a waves due to the loss of AV synchronization and contraction of the atria against a closed tricuspid valve
• Atrial fibrillation: absent a waves due to ineffective contraction of the atria

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