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Heart Murmurs at a Glance

by | 27 Mar, 2020

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Normal Heart Sounds

Normally, only heart sounds S1 and S2 can be heard. Murmurs occur if there is turbulent blood flow, which usually occurs as a result of valve pathology.
Normal heart sounds

Normal heart sounds and timing of pulse

Systolic Murmurs

Type Ejection systolic Pansystolic
Characteristics ejection systolic murmur midsystolic murmur
Causes
  1. Aortic stenosis
  2. Pulmonary stenosis
  3. Hypertrophic obstructive cardiomyopathy (HOCM)
  4. Atrial septal defect
  5. Tetralogy of Fallot
  1. Mitral regurgitation
  2. Mitral valve prolapse
  3. Tricuspid regurgitation
Mechanism of murmur Turbulent blood flow caused by travelling through tight space Blood travels back into the heart against normal blood flow

Diastolic Murmurs

Type Early diastolic Mid-diastolic
Characteristics early diastolic murmur middiastolic murmur
Causes
  1. Aortic regurgitation
  2. Pulmonary regurgitation
  1. Mitral stenosis
  2. Tricuspid stenosis
Mechanism of murmur Blood travels back into the heart against normal blood flow Turbulent blood flow caused by travelling through tight space

Continuous/Machinery murmurs

Continuous murmurs occur when there is a pressure gradient present throughout the cardiac cycle. Thus, the murmur is heard during both systole and diastole.

Causes

Patent ductus arteriosus

Flow murmurs

Flow murmurs are innocent, benign murmurs that are especially common in young patients. They are characterised by the following:
  1. Systolic only
  2. Sound soft
  3. Varies with posture
  4. No thrill present
  5. Asymptomatic

References and Further Reading

Source of heart murmur sounds: University of Michigan Murmur library

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