Understanding Different Pulse Characteristics

May 12, 2025

Lecture Notes on Pulse Character

Introduction

  • Character of Pulse
    • Best felt in carotid arteries, except for pulsus bisferiens and pulsus alternans (radial artery preferred)
    • Normal pulse character: cataclytic type
    • Pulse is the pressure waveform of the left ventricle contraction

Normal Pulse Waveform

  • Pressure Transmission
    • Left ventricle contraction transmits pressure to aortic and then carotid walls, producing the percussion wave
    • Tidal wave: Blood from left ventricle to aorta and carotid
  • Dicrotic Notch
    • Occurs as aortic valve shuts, causing a transient increase in pressure
    • Followed by a decrease in pressure as blood flows to peripheries and left ventricle relaxes

Pathological Pulse Characters

Pulsus Parvus

  • Characteristics: Decreased amplitude of tidal wave
  • Causes: Decreased blood to carotids, e.g., shock, mitral stenosis, heart failure, dilated cardiomyopathy, aortic stenosis

Pulsus Tardus

  • Characteristics: Increased time duration of wave
  • Causes: Obstruction in left ventricular outflow (e.g., aortic stenosis) or delayed myocardial contraction (e.g., left bundle branch block)

Pulsus Parvus et Tardus

  • Combination of: Pulsus parvus and pulsus tardus
  • Cause: Aortic stenosis

Pulsus Bisferiens

  • Characteristics: Two peaks palpable before S2 in systole
  • Causes: Increased time gap between percussion and tidal waves (e.g., HOCM, severe aortic regurgitation)

Pulsus Dicroticus

  • Characteristics: Two peaks (one before S2, one after S2)
  • Causes: Increased amplitude of dicrotic notch due to increased peripheral vascular resistance (e.g., shock)

Pulsus Alternans

  • Characteristics: Alternating pulse amplitude in each cycle
  • Cause: Severe heart failure, due to varying cardiac output as per Frank-Starling law
  • Important Note: Distinct from electrical alternans (alternating ECG voltage in cardiac tamponade)

Electrical Alternans

  • Characteristics: Alternating voltage amplitude in ECG
  • Cause: Cardiac tamponade (heart floating in fluid affects proximity to chest wall)
  • Important Note: Pulse amplitude remains normal in these patients

Conclusion

  • Summary: Different pulse characters provide insights into cardiovascular pathology and require careful distinction, particularly between mechanical and electrical phenomena.

Note: Understanding the specific conditions and effects on the waveform is critical for accurate diagnosis and treatment.

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