Hello,

Pulsus alternans (the variation of one strong and one weak beat without an alteration in cycle length all through pulse palpation) is most prevalent in heart failure, which is caused by greater resistance to LV ejection, as seen in hypertension, aortic stenosis, coronary atherosclerosis, and dilated cardiomyopathy.

One concept is that with left ventricular failure, the ejection fraction decreases considerably, resulting in a drop in stroke volume and, as a result, an increase in end-diastolic volume. As a result, the myocardial muscle will be stretched more than normal during the next systolic phase, resulting in an increase in myocardial contraction, as described by the Frank–Starling physiology of heart.

As a result, the systolic pulse becomes stronger. A tachycardia may develop at first as a compensatory strategy to maintain cardiac output. Another possibility is that the refractory time differs between healthy and sick cardiac cells.

Hope it helped

Thank you