Pulsus alternans
Pulsus alternans | |
---|---|
Other names | Cardiac alternans, mechanical alternans |
Pulse pressure waveform displaying the variation in pressure between beats in pulsus alternans. | |
Specialty | Cardiology |
Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats.[1] It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis.
Pathophysiology
One explanation is that in left ventricular dysfunction, the ejection fraction will decrease significantly, causing reduction in stroke volume, hence causing an increase in end-diastolic volume. As a result, during the next cycle of systolic phase, the myocardial muscle will be stretched more than usual and as a result there will be an increase in myocardial contraction, related to the Frank–Starling physiology of the heart. This results, in turn, in a stronger systolic pulse. There may initially be a tachycardia as a compensatory mechanism to try to maintain cardiac output. Other explanation is due to the heterogeneity of the refractory period between the healthy and diseased myocardial cells.[citation needed]
Diagnosis
Begin by palpating the radial or femoral arteries, feeling for a regular rhythm but alternating strong and weak pulses. Next use a blood pressure cuff to confirm the finding: Inflate the blood pressure cuff past systolic pressure and then slowly lower cuff pressure towards the systolic level. If alternating loud & soft Korotkoff sounds are heard, pulsus alternans is indicated.[2]
Clinical significance
A finding of pulsus alternans is indicative of severe left-sided heart failure. [3]
In literature
D.H. Lawrence elegantly describes pulsus alternans in his novel Sons and Lovers:
Then he felt her pulse. There was a strong stroke and a weak one, like a sound and its echo. That was supposed to betoken the end....
References
- ^ Euler, DE (June 1999). "Cardiac alternans: mechanisms and pathophysiological significance". Cardiovascular Research. 42 (3): 583–90. doi:10.1016/s0008-6363(99)00011-5. PMID 10533597.
- ^ Bates
- ^ (Bates)
External links