Page 54 - Clinical Pearls in Cardiology

42 Clinical Pearls in Cardiology

Table 3: Clinical difference between atrial fibrillation and
multiple ectopics
Atrial fibrillation Multiple ectopics
Pulse rate more than 100 Pulse rate less than 100 per
per minute minute
Pulse deficit more than 10 Pulse deficit less than 10
Exercise accentuates the Exercise attenuates or abolishes
irregularity the ectopics
Absent “a” wave in JVP “a” wave present in JVP

19. What is meant by pulse deficit?
Pulse deficit is a clinical sign where there is a difference
in count between the auscultated heart beat and
the palpated peripheral pulse. This can occur in few
clinical situations like atrial fibrillation and multiple
irregular ventricular ectopic beats. Some ventricular
contractions are too weak, and are unable to open the
aortic valve and produce the peripheral pulse. But these
contractions are good enough to close the mitral valve
and produce S1. This produces more audible heart
sounds, but less number of pulses in the periphery. The
weak ventricular contractions are because of the varying
R-R interval in conditions like atrial fibrillation. Hence
the duration of diastole and the extent of ventricular
filling varies. Some of the diastoles are too short, and
the left ventricle hardly gets filled. Since the force of
contraction of the left ventricle is dependent on the left
ventricular end diastolic volume (according to Starling’s
law), the resultant ventricular contraction will be weak
and will not produce a palpable pulse. Hence the
auscultated apical rate will be higher than the palpated
pulse rate. The pulse deficit is the difference between
the auscultated heart rate and the palpated pulse rate.