What is an apex pulse deficit?

What is Apex Pulse Deficit?

Apex pulse deficit (also called apical-radial pulse deficit) is the numerical difference between the apical heart rate (counted by auscultation at the cardiac apex) and the peripheral pulse rate (counted at a radial or other peripheral artery), measured simultaneously over the same time period. 1

Clinical Measurement

• The deficit is calculated by having one examiner count the apical heartbeat using a stethoscope placed at the point of maximal impulse while a second examiner simultaneously counts the radial pulse, both for a full 60 seconds 1
• The apex pulse deficit equals: (Apical heart rate) - (Peripheral pulse rate) 1
• A pulse deficit exists when some cardiac contractions fail to generate sufficient stroke volume to produce a palpable peripheral pulse wave 2

Pathophysiology

The primary mechanism producing pulse deficit is inadequate left ventricular filling time and reduced preload, resulting in insufficient stroke volume to generate a detectable peripheral pulse. 2

• In atrial fibrillation specifically, the irregular ventricular response creates varying diastolic filling periods—very short RR intervals provide insufficient time for ventricular filling, producing weak or absent peripheral pulse waves despite audible heart sounds 2
• Reduced left ventricular contractility significantly contributes to pulse deficit, with studies showing patients having pulse deficit demonstrate significantly lower ejection fractions (41 ± 12% vs 59 ± 7%) and fractional shortening (20 ± 6% vs 31 ± 5%) compared to those without deficit 2
• Systolic backward flow in the mid-ventricle caused by left ventricular asynchrony and localized apical wall motion abnormalities has been observed in all patients with pulse deficit 2

Clinical Significance and Associated Conditions

Pulse deficit most commonly signals atrial fibrillation with irregular ventricular response, but can indicate other serious cardiac pathology. 3, 1

• Patients with bigeminy (alternating normal and premature beats) characteristically present with pulse deficit, effective bradycardia, and relative hypertension with wide pulse pressure 3
• In acute type A aortic dissection, pulse deficits (decreased or absent carotid or peripheral pulses) occur in 30% of patients and independently predict 5-day in-hospital mortality (risk ratio 2.73,95% CI 1.7-4.4) 4
• Overall mortality rates in aortic dissection increase progressively with the number of pulse deficits present 4
• Higher pulse deficits correlate strongly with exercise intolerance in permanent atrial fibrillation patients, with mean deficit of 17 ± 4 beats/min in exercise-intolerant patients versus 12 ± 2 in those with adequate capacity 5

Clinical Implications for Management

• Pulse deficit magnitude correlates positively with heart rate (r = 0.431) in atrial fibrillation, suggesting rate control importance 5
• Rhythm control strategy should be considered in persistent atrial fibrillation patients with high pulse deficit and exercise intolerance to improve left ventricular filling pressures 5
• The presence of pulse deficit in acute chest pain should prompt immediate consideration of aortic dissection diagnosis and more aggressive diagnostic strategies 4
• Regular monitoring of pulse deficit is essential when patients have irregular pulse rhythms to detect arrhythmias and assess hemodynamic compromise 1

Common Pitfalls

• Effective bradycardia from pulse deficit can result in inaccurate heart rate estimation if only peripheral pulse is counted, potentially leading to inappropriate management decisions 3
• Single-examiner sequential measurement (rather than simultaneous dual-examiner assessment) reduces accuracy and should be avoided 1
• Pulse deficit may be overlooked in routine vital sign assessment when only peripheral pulse is documented, missing important diagnostic and prognostic information 1, 4