Important characteristics of pulses to consider include:
- Rate: The rate of the pulse is the number of times the artery expands and contracts in one minute. This is also known as the heart rate, and is typically measured in beats per minute (bpm). A normal heart rate for an adult is between 60-100 bpm. A heart rate that is too fast or too slow can indicate a problem with the heart or cardiovascular system.
- Rhythm: The rhythm of the pulse is the pattern of expansion and contraction. A regular rhythm is when the pulses are evenly spaced and of equal strength. An irregular rhythm can indicate a problem with the heart’s electrical system, such as atrial fibrillation.
- Volume: The volume of the pulse refers to the strength of the expansion and contraction. A strong pulse indicates good blood flow, while a weak pulse can indicate poor blood flow or a decrease in cardiac output.
- Character: The character of the pulse refers to the shape of the expansion and contraction pressure waves. A regular character indicates that the pulse is consistent in shape and duration. An irregular character can indicate a problem with the heart’s structure or function.
The character of a pulse refers to its strength and volume, and can suggest various pathologies. The carotid pulse should be used when assessing the character of the pulse; palpation should show a smooth rapid upstroke and a more gradual downstroke with each pulse.
Pathological pulse characters
Waterhammer/Large volume pulse
A waterhammer pulse has a sharper upstroke and increased amplitude. It is typically caused by aortic regurgitation.
A slow-rising pulse has, as the name suggests, a slower upstroke and reduce amplitude. It is typically caused by aortic stenosis
Pulsus bisfiriens has a character of two narrowly separated peaks during systole. It is caused by mixed aortic stenosis with aortic regurgitation valve disease.
Pulsus alternans develops in left ventricular systolic impairment. The pulse alternates between low and high volume; a low ejection fraction produces the low volume pulse, which leads to ventricular filling and a stronger contraction in the subsequent pulse due to Startling’s law.
Pulses paradoxus refers to a large drop in pulse volume (corresponding to >10mmHg blood pressure) upon inspiration.
- Pericardial effusion
- Severe asthma
Double impulse apex beat
When palpating the apex beat, a feeling of 2 beats within a single systole is suggestive of hypertrophic obstructive cardiomyopathy (HOCM).
Absent radial pulse
Occasionally, a radial pulse may be completely absent and cannot be palpated or found on ultrasound.
- Iatrogenic e.g. post-catheterisation, radial artery harvest
- Congenital absence
- Aortic dissection involving the subclavian artery
- Peripheral artery embolism
- Compression by cervical rib
- Takayasu’s arteritis
- Morris DC. The Carotid Pulse. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 20. Available from: https://www.ncbi.nlm.nih.gov/books/NBK312/