From the Guidelines
A pulse deficit is a significant clinical sign that may indicate compromised cardiac output and should prompt further cardiac evaluation, particularly in the context of suspected thoracic aortic dissection, as it is listed as a high-risk examination feature 1. Pulse deficit is defined as the difference between the heart rate measured by auscultation and the pulse rate felt at a peripheral artery, typically the radial artery. This discrepancy can occur due to various cardiac conditions, including atrial fibrillation, premature beats, heart blocks, and severe heart failure.
Causes and Measurement
- Atrial fibrillation is a common cause of pulse deficit, where irregular heart contractions result in varying stroke volumes, with some contractions being too weak to generate a detectable peripheral pulse.
- Other causes include premature beats, heart blocks, and severe heart failure.
- To measure a pulse deficit, simultaneously count the heart rate (by listening to the heart with a stethoscope) and the peripheral pulse rate (by palpating an artery) for one minute, then calculate the difference.
Clinical Significance
- A significant pulse deficit may indicate compromised cardiac output and should prompt further cardiac evaluation, particularly in patients presenting with sudden onset of severe chest, back, and/or abdominal pain 1.
- In the context of suspected thoracic aortic dissection, a pulse deficit is considered a high-risk examination feature, along with other signs such as systolic blood pressure limb differential greater than 20 mm Hg, focal neurologic deficit, and murmur of aortic regurgitation (new) 1.
Treatment and Management
- Treatment focuses on addressing the underlying cardiac condition rather than the pulse deficit itself, which is a clinical sign rather than a disease.
- In emergency situations, a pulse deficit may signal deteriorating cardiac function requiring immediate medical attention, and patients should be questioned about a history of aortic pathology, recent aortic manipulation, or known history of aortic valvular disease 1.
From the Research
Significance of Pulse Deficit
- Pulse deficit is the difference between the apical and peripheral pulse rates, and it can signal an arrhythmia 2.
- In patients with atrial fibrillation, pulse deficit is a frequently unused but crucial clinical finding 3.
- A higher pulse deficit is associated with decreased exercise capacity in persistent atrial fibrillation patients 3.
- Pulse deficit is independently associated with exercise intolerance after adjusting for potential covariates 3.
Relationship with Atrial Fibrillation
- Atrial fibrillation is the most common sustained arrhythmia in adults and has unfavorable consequences such as stroke, heart failure, and death 4.
- Pulse deficit can be used to diagnose atrial fibrillation, and it may be useful in identifying patients who would benefit from rhythm control strategy 3.
- The relationship between pulse deficit and atrial fibrillation is complex, and further studies are needed to fully understand its significance 3.
Clinical Implications
- Monitoring pulse deficit is important in patients with irregular pulse rhythm 2.
- Pulse deficit can be used to assess the effectiveness of treatment in patients with atrial fibrillation 3.
- A higher pulse deficit may indicate a poorer prognosis in patients with atrial fibrillation, and it may be useful in identifying patients who require more aggressive treatment 3.