Pulse rate and contour

Pulsus alternans

  • REGULAR pulse with strong and weak beats (distinguished from bigeminal pulse which is IRREGULAR)
  • Pathogenesis:
    – Hemodynamic argument: sudden increase in ventr.filling causes the subsequent systole to be stronger; this shortens the next diastole which leads to weaker next systolic beat
    – Contractility argument: alternation in intrinsic contractility, explains why the pulse starts when there is no pause in the rhythm from extrasystole or tachycardia
  • Indicates: LV dysfunction

Pulsus bisfiriens

  • Pulse with 2 beats per SYSTOLIC cycle (percussion and tidal wave)
  • Pathogenesis: rapid ejection of blood into aorta causing a Venturi effect
  • Indicates: mod-severe aortic regurg
    ** Can be found in HOCM too but normally in intra-arterial pressure tracing

Pulsus paradoxus

  • Exaggerated decrease of SBP during inspiration >12 mmHg
  • Technique:
    – Can be noted in pulse oximetry tracings
    – By BP cuff: patient is asked to breathe normally. The cuff is deflated to
    i) The moment the Korotkoff sound first appears. Cuff pressure will fall below SBP during expiration, and therefore the sound will come and go during resp.
    ii) The moment when the Korotkoff sound is heard throughout the resp
    iii) The moment wjem Korotkoff sounds disappear (diastolic pressure)
    PP = (i) – (ii)
  • Indicates
    – Cardiac tamponade (most sens finding)
    – Asthma (sens is lower, although PP of >20 indicates severe asthma)
  • Tamponade WITHOUT PP
    – Equalization of pressure between RV and LV due to communication (ASD) or LV pressure is very high (LVF or aortic valve diseases)
    – Regional tamponade
  • Reversed PP
    – Expiratory drop of SBP > 10 mmHg, seen in
    i) HOCM
    ii) isorrhythmic dissociation
    iii) IPPV in the presence of LVF

Pulsus parvus et tardus

  • Small (parvus) and delayed (tardus) pul
  • Indicates severe AS
    – Other indicators: HF failure, displaced apex beat, thrills, absent/soft S2, S2 reversal, presence of S4, delayed ESM
  • Note, it depends on compliance of vessels
    – In stiff vessels, the pulse waveform rises rapidly, but slowly in more compliant vessels.

Dicrotic pulse

  • Like bisfiriens pulse, but one peak is systolic another is diastolic. Difference to pulsus bisfiriens is pul.bisfiriens occurs in SYSTOLIC cycle
  • Pathogenesis: amplified “normal dicrotic wave” normally seen in arterial pressure tracing

    – Low stroke volume which dampens the systolic wave, making the diastolic wave more noticeable
    – Compliant arterial system which amplifies the rebound of the arterial pulse
  • Indicates: young patiets with severe myocardial dysfunction

Hyperkinetic pulse

  • Normal pulse pressure (HCM, MR etc)
  • Increase PP (AR)

Pulse and BP

  • In ATLS, we were taught that
    – Carotid pulse palpated: SBP 60-70 mmHg
    – Carotid + femoral pulse: 70-80 mmHg
    – Radial pulse: >80 mmhg
  • Evidence: ATLS overestimates SBP based on palpation of radial, femoral, & carotid pulses. Do not rely on pulse to predict patient’s volume !




Steven McGee, Evidence based physical diagnosis, pg 121-139



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