The Pulse

The Pulse

Pulse characteristics are often assessed at the radial and carotid arteries. However, all of the peripheral pulses should be examined. Palpation of both radial pulses simultaneously and a radial and femoral pulse together will help establish the presence of obstructive disease in the more proximal segments of the arterial tree.

The initial assessment of pulse rate, volume and character is usually obtained from the radial pulse. The radial pulse is typically on the radial side of the palmer aspect of the wrist, about two centimetres proximal to the thenar eminence. The pulse is gently gripped with the index finger on the palmer side of the wrist and the thumb on the dorsum of the wrist. The brachial pulse is on the medial and anterior part of the elbow crease. The femoral pulse can be palpated below the inguinal ligament. Be sure to explain to the patient what you are doing before attempting to palpate the femoral pulse!


Taking the radial pulse
Source Wikipedia

Radio-femoral delay is classically attributed to coarctation of the aorta, usually due to narrowing of the aorta just beyond the origin of the left subclavian branch. It is more often seen in young men. Sometimes a noticeably lower pulse volume in the femoral artery compared to radial artery is all that is appreciated rather than the classic delay in the femoral pulse. In older patients, radial femoral delay can potentially occur due to differences in peripheral artery calcification and stiffness between the lower limbs and upper limbs arteries. Typically stiffer arteries lead to an increase in pulse wave velocity with more rapid propagation of the pulse wave. These patients also tend to have hypertension. Although advanced atherosclerosis or arteriosclerosis may be a more common cause in the elderly, coarctation is sometimes diagnosed in older adults and should not be dismissed because of older age.

Rate

The emergence of automatic blood pressure and heart rate measurement by machine has tended to diminish the practice of manually estimating heart rate. However, machines can be wrong, particularly with arrhythmia and a manual assessment should assess the accuracy of any machine reading.

Count the number of beats per minute. It is often convenient to count the number of beats over 15 seconds and then multiply by four. If the pulse is slow or irregular however, counting over a full 60 seconds will be more accurate. A normal resting heart rate ranges between 60 and 100 beats per minute. Highly trained athletes may have heart rates well below this range. A slow pulse (less than 60 bpm) is termed bradycardia. A fast heart rate (greater than 100 bpm) is termed tachycardia.

It is a normal for the pulse rate to vary slightly with respiration, particularly in the young, called sinus arrhythmia. This arrhythmia is related to differential filling of the left and right side of the heart and vagal tone with inspiration and expiration. Typically the heart rate increases slightly during inspiration, and decreases with expiration. As it is partly mediated by vagal tone, this effect, like vagal tone, tends to decline with age.

Rhythm

The pulse is regular with sinus rhythm (apart from the caveat of sinus arrhythmia described above). A very rapid regular rhythm may indicate sinus, supraventricular or ventricular tachycardia. An irregular pulse can be regularly irregular (a recurring pattern such as bigeminy or type II heart block) or irregularly irregular (no clear pattern, such as atrial fibrillation).

Volume

The volume of the pulse is best assessed by palpating one of the larger arteries such as the carotid, brachial or femoral pulses. It is a subtle sign that requires experience over many years and many patients for the examiner to recognize low and high volume pulses. Some examiners prefer to use the thumb to palpate carotid and brachial pulses. A semi-quantitative scale is used to describe pulse volume (increased, normal, reduced, absent)

Character


(figures )

This refers to an impression of the pulse waveform derived during palpation. Again, like volume, it needs to be examined at one of the large arteries.

Some abnormalities of pulse are described below.

Anacrotic pulse



This is seen in aortic stenosis, and refers to a pulse wave that is slow rising and generally flat volume associated with a low cardiac output and prolonged left ventricular ejection time. It suggests more severe aortic stenosis.

Bisferiens Pulse


This is a more difficult pattern to recognize and is best palpated over the carotid arteries. It is characterized by two systolic peaks and is seen in aortic regurgitation with or without aortic stenosis, and in some patients with hypertrophic cardiomyopathy.

Diacrotic pulse


This is also a pulse with two peaks- one in systole and the other in early diastole. It may be seen after the administration of nitrates in otherwise normal subjects, in febrile patients or in cardiac tamponade, congestive cardiac failure or shock, where a ventricular contraction delivers a small volume of blood into a non rigid arterial circulation.

Plateau pulse



A slow rising pulse with a flattened peak. This is seen in severe aortic stenosis

Collapsing pulse


This is a sign of aortic regurgitation, although it is sometimes also seen in patients with a hyperdynamic circulation and with a rigid arterial system. A stiff arterial system leads to an accentuated systolic peak in the peripheral pulses. The pulse has an early peak and then quickly falls away, giving it a tapping quality. The preferred method is to palpate the brachial pulse with the whole palm applied to the flexor aspect of the wrist (Your colleagues will be impressed with your clinical skills!). The collapsing pulse is also referred to as Corrigans or a water-hammer pulse, after a 19th century toy that was a vacuum tube containing water or mercury that was flipped creating a tapping or hammer sensation at the finger tips (a most arcane term – perhaps the Game-Boy rumble would be more recognizable today).. This accentuates the tapping quality of the pulse.

When a collapsing pulse is detected look for the following signs, although these are rarely seen in societies where advanced bacterial endocarditis is rare or where advanced cardiac imaging is performed for the mildest of valvular abnormalities.

Duroziez sign: Seen in severe aortic regurgitation. Place the diaphragm of the stethoscope over the femoral artery and press downwards. Initially a systolic murmur will be heard. Gradually increase pressure over the artery- a diastolic murmur will become evident also related to the flow reversal with profound aortic regurgitation. Now tilt the proximal edge of the stethoscope further downwards – if aortic regurgitation is present the systolic murmur is accentuated and the diastolic component is diminished. Now tilt the distal edge of the stethoscope downwards, the diastolic component will now be accentuated and the systolic reduced. This sign has a positive predictive value of close to 100% for aortic regurgitation, and can detect this lesion in some patients in whom it is not possible to hear the characteristic diastolic murmur on auscultation of the heart (e.g. acute aortic regurgitation due to acute bacterial endocarditis).

Traubes sign: A “pistol shot” sound heard over the femoral artery with the aid of a stethoscope. It is necessary to compress the femoral artery distal to the stethoscope head to produce the characteristic double tone sound.

Hills sign: This is a nonspecific sign of aortic regurgitation- it is also seen in other causes of a hyperdynamic circulation, such as thyrotoxicosis, beri-beri, or pregnancy. Check the blood pressures in the upper and lower limbs. If the pressure in the lower limbs exceeds that in the upper limbs by more than 20 mmHg then the sign is positive.

Quinkes sign: Pulsatile blanching of the nail bed

De Musset’s sign: Named after the famous French poet whose head nodded in time with his arterial pulsations due to his syphilis related aortic regurgitation.

Pulsus paradoxus


This is a misnomer. This is an exaggerated physiological phenomenon, rather than a paradox as the name implies. The volume of the pulse rises with expiration with the increase in stroke volume. and falls during inspiration When it is present, it suggests either restricted left ventricular filling during inspiration (associated with a mild increases in pericardial pressure and increased right heart filling that shifts the interventricular septum towards the left ventricle to impair left sided filling) such as in pericardial tamponade, or exaggerated changes in intrathoracic pressure as in severe asthma.. Other causes of pulsus paradoxus include right ventricular infarction, large pulmonary embolus, and tense ascites or obesity.

Pulsus paradox is quantified by measuring a change in systolic blood pressure from inspiration to expiration of greater than 12 mmHg or 10% of systolic pressure. To successfully measure this, inflate the brachial cuff pressure to beyond systolic pressure. Palpate the brachial pulse and note the pressure it returns on expiration. Slowly decrease the pulse until you can identify the brachial pulse on inspiration. The difference in systolic pressure is used to estimate the magnitude of pulsus paradox.

Pulsus alternans


This abnormality describes a pulse that alternates between a larger and smaller volume on a beat to beat basis. This is a regular pulse and is seen in severe cardiac failure.

Pulsus bigeminus


This is often confused with pulsus alternans. Here after every other normal beat at a shorter than usual interval there is a lower volume beat, usually due to a premature ventricular contraction. It does not imply severe cardiac failure. A common cause now is Digoxin toxicity.

Jerky pulse


This is often seen in hypertrophic cardiomyopathy as the hypertrophied ventricle rapidly empties and then quickly drops its output as the outflow pathway is obstructed.