Patterns in heart murmurs

Question 1

Basic Patterns

Answer 1

• The mitral disorders (regurgitation & stenosis) cause increased LA pressures (predisposing to AF), either by obstructed flow (MS) or retrograde flow (MR) leading to PULMONARY VENOUS CONGESTION (pulmonary oedema causing dyspnoea) which increases afterload at the pulmonic valve (pulmonary HTN) and leads to signs of RHF
  
  • MS mostly due to Rheumatic Fever
  • MR mostly caused by post-MI papillary muscle dysnfunction
• However in Chronic MR there is associated LA & LV hypertrophy due to the increased pressures caused by backflow into a non-compliant atrium –> leads to systolic failure so S3 & LAT. DISPLACED APEX
• The aortic disorders (regurgitation & stenosis) cause increased LV pressures, either by obstructed flow (AS) or retrograde flow (AR) which lead to REDUCED CARDIAC OUTPUT. The signs seen reflect this (e.g. angina & dyspnoea). Initially, there is compensation (concentric hypertrophy in AS to pump more forcefully & eccentric hypertrophy to accommodate increased EDV). These compensatory mechanisms then fail and ventrivular output decreases, forcing blood into pulmonary venous system.
• Signs that are only seen in Aortic pathology:
  
  • Pulse pressure changes (wide in AR, narrow in AS)
  • Extra heart sounds due to LV remodelling (S3 in AR, S4 in AS) - S3 in MR
• The tricuspid disorder (regurgitation) is mostly secondary to LHF (which causes symptoms of RHF like RV dilation) so signs of LHF will precede those of RHF