Abnormal pulses: paradoxus, alternans, parvus et tardus, bounding !

Sign

The shape of the pulse, not just its rate, gives away heart problems: a pulse that weakens on inspiration, alternates or arrives late.

Updated 2026-11-01

See it in 3D: Radial artery · Common carotid artery · Pericardium · Aortic right coronary cusp · Left ventricle

What it is

Palpating the carotid or radial assesses amplitude, upstroke and regularity. Some patterns are nearly diagnostic: pulsus paradoxus in tamponade, parvus et tardus in severe aortic stenosis, a bounding pulse in aortic regurgitation and pulsus alternans in severe ventricular failure.

The anatomy it tests

Paradoxus: on inspiration the right ventricle fills more; if the pericardium prevents expansion, the septum shifts into the left ventricle and stroke volume falls.
Parvus et tardus: the narrowed aortic valve lets blood out slowly and in small volume.
Bounding (water-hammer): large stroke volume and rapid diastolic fall from aortic regurgitation or a hyperdynamic circulation.
Alternans: a very depressed left ventricle alternates strong and weak beats in a regular rhythm.

How to elicit it

Feel the carotid (one side at a time, mid-neck) for waveform; the radial for rate and rhythm.
Judge amplitude (weak, normal, bounding), upstroke (slow or brisk) and beat-to-beat variation.
Pulsus paradoxus: deflate the cuff slowly; note where sounds are heard only in expiration and where they are heard throughout breathing.
If the difference between them is more than 10 mmHg, pulsus paradoxus is present.
If the rhythm is irregular, count a full minute and compare apical with radial rate (pulse deficit).

What a positive result means

Paradoxus (inspiratory systolic fall of more than 10 mmHg): cardiac tamponade, severe asthma or COPD exacerbation, massive pulmonary embolism; less often constrictive pericarditis.
Parvus et tardus: severe aortic stenosis.
Bounding with a wide pulse pressure: aortic regurgitation; also anemia, fever, hyperthyroidism, pregnancy, arteriovenous fistula, patent ductus arteriosus.
Alternans: heart failure with severe systolic dysfunction.
Bisferiens (two systolic peaks): aortic regurgitation with or without stenosis, hypertrophic cardiomyopathy.
Irregularly irregular with a pulse deficit: atrial fibrillation.

Usefulness and limits

Pulsus paradoxus is lost in arrhythmias or extreme hypotension; it may be absent in tamponade with an atrial septal defect or aortic regurgitation.
Waveform is judged better at the carotid than at the radial.

Test yourself

Think of the answer, then tap the question to see it.

How is pulsus paradoxus defined?

As a fall in systolic pressure of more than 10 mmHg during inspiration.

Which pulse is typical of severe aortic stenosis?

Pulsus parvus et tardus: small and slow-rising, best felt at the carotid.

What does pulsus alternans with a regular rhythm suggest?

Heart failure with severe left ventricular systolic dysfunction.

Why is only one carotid palpated at a time?

To avoid reducing blood flow to both sides of the brain and to avoid stimulating the carotid sinus.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

← All of the clinical exam

Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: Pulse: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2026); Cardiac tamponade: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2026); Aortic regurgitation: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2026); Aortic stenosis: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2026).

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Representative model, for educational purposes only.