Pulse deficit describes a difference between heartbeats heard directly over the heart and beats felt at a peripheral artery, such as the wrist. This discrepancy indicates how effectively the heart pumps blood, as not every contraction may generate a strong enough wave to be felt peripherally. Assessing this difference can highlight underlying cardiovascular issues.
Understanding Apical and Radial Pulses
To determine a pulse deficit, two specific pulse measurements are necessary: the apical pulse and the radial pulse. The apical pulse represents the actual rate at which the heart is contracting and is typically heard by placing a stethoscope over the apex of the heart, usually located on the left side of the chest. This direct auscultation provides the true ventricular rate.
The radial pulse, in contrast, is the pulse felt at the wrist, specifically on the thumb side. This peripheral pulse reflects the number of heartbeats that successfully generate a palpable pressure wave in the arteries far from the heart. Comparing these two measurements allows healthcare professionals to identify if all heart contractions are effectively translating into peripheral blood flow.
Calculating the Deficit
Calculating a pulse deficit requires simultaneous measurement of both the apical and radial pulses, typically involving two individuals for accuracy. One person listens to the apical pulse using a stethoscope while the other simultaneously palpates the radial pulse at the wrist. Both individuals need a watch with a second hand or a digital timer to count the beats over a full minute.
The person listening to the apical pulse counts each heartbeat heard through the stethoscope for 60 seconds. Simultaneously, the second person counts each palpable radial pulse felt at the wrist for the same 60-second duration. It is crucial that both counts begin and end precisely together to ensure a valid comparison. Once both counts are completed, the radial pulse rate is subtracted from the apical pulse rate. For example, if the apical pulse is 80 beats per minute and the radial pulse is 70 beats per minute, the pulse deficit would be 10.
What Your Pulse Deficit Means
A zero pulse deficit, where the apical and radial pulse rates are identical, indicates every heartbeat effectively generates a palpable peripheral pulse. This is considered normal and suggests efficient blood circulation. A positive pulse deficit means the apical rate is higher than the radial rate, signifying some heartbeats are too weak to produce a detectable pulse wave at the wrist.
This discrepancy often points to conditions where the heart’s contractions are irregular or weak, preventing adequate blood flow to the extremities. For instance, atrial fibrillation can cause chaotic upper chamber beats, leading to ineffective ventricular contractions. This occurs because irregular heart contractions can result in varying stroke volumes, with some contractions being too weak to generate a detectable peripheral pulse. Premature ventricular contractions (PVCs) can also result in a deficit if they occur too early or are too weak to propagate a peripheral pulse, as these early contractions are often ineffective at pumping blood.
A pulse deficit is clinically significant when the difference between the apical and peripheral pulse rate exceeds 10 beats per minute. This suggests some heartbeats are not generating enough cardiac output for a palpable peripheral pulse. While temporary factors like physical activity can influence it, a persistent positive deficit may signal compromised cardiac output. Any detected pulse deficit warrants medical consultation to investigate the underlying cause and determine appropriate management.