Exam

Point of Maximum Impulse

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Point of Maximum Impulse, Apical Thrust, Displaced Cardiac Apex, PMI

  • Mechanism
  1. Heart apex rotates forward with systole
  • Normal impulse location
  1. Fifth intercostal space
  2. Left of mid-Sternum by 7 to 9 cm
  3. Medial to left midclavicular line by 1-2 cm
  • Accentuated Impulse
  1. Findings suggestive of Left Ventricular Hypertrophy
    1. Impulse > 3 cm diameter (stethoscope diaphragm size)
      1. Patient in Left Lateral Decubitus
      2. Palpation of apex
    2. Accuracy (Compared with Echocardiogram)
      1. Sensitivity: 92%
      2. Specificity: 91%
    3. Reference
      1. Eileen (1983) Ann Intern Med 99(5):628-30 [PubMed]
  2. Causes
    1. Left Ventricular Hypertrophy
    2. Increased myocardial tone
      1. Exertion
      2. Emotion
      3. Thyrotoxicosis
      4. Digoxin Toxicity
  • Shifted Position of PMI
  1. PMI shifted left
    1. Cardiac dilatation suggestive of CHF
      1. Test Sensitivity: 66%
      2. Test Specificity: 95%
    2. Other causes
      1. Right Pneumothorax
      2. Left pleural adhesions
  2. PMI shifted right
    1. Left Pneumothorax
    2. Right pleural adhesions
  • References
  1. Degowin (1987) Bedside Diagnostics, Macmillan, p. 344