Pulsus alternans
Encyclopedia
Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis.
will decrease significantly, causing reduction in stroke volume
, hence causing a increase* in end-diastolic volume
. There may initially be a tachycardia as a compensatory mechanism to try to keep the cardiac output constant. As a result, during the next cycle of systolic phase
, the myocardial muscle will be stretched more than usual and as a result cause an increase in myocardial contraction, related to the Frank–Starling physiology of the heart. This results, in turn, in a stronger systolic pulse
.
" elegantly describes pulsus alternans:
"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."
Pathophysiology
In left ventricular dysfunction, the ejection fractionEjection fraction
In cardiovascular physiology, ejection fraction is the fraction of Blood pumped out of the Right Ventricle of the heart to the Pulmonary Circulation and Left Ventricle of the heart to the Systemic Circulation with each Heart beat or Cardiac cycle...
will decrease significantly, causing reduction in stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
, hence causing a increase* in end-diastolic volume
End-diastolic volume
In cardiovascular physiology, end-diastolic volume is the volume of blood in the right and/or left ventricle at end Load or filling in . Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in...
. There may initially be a tachycardia as a compensatory mechanism to try to keep the cardiac output constant. As a result, during the next cycle of systolic phase
Systole (medicine)
Systole is the contraction of the heart. Used alone, it usually means the contraction of the left ventricle.In all mammals, the heart has 4 chambers. The left and right ventricles pump together. The atria and ventricles pump in sequence...
, the myocardial muscle will be stretched more than usual and as a result cause an increase in myocardial contraction, related to the Frank–Starling physiology of the heart. This results, in turn, in a stronger systolic pulse
.
In literature
D.H. Lawrence, in his famous novel, "Sons and LoversSons and Lovers
Sons and Lovers is a 1913 novel by the English writer D. H. Lawrence. The Modern Library placed it ninth on their list of the 100 best novels of the 20th century.-Plot introduction and history:...
" elegantly describes pulsus alternans:
"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."