What is pulsus alternans and which cardiomyopathy is it associated with?

Pulsus alternans is characterized by a regular rhythm with alternating strong and weak pulses, indicating a significant change in stroke volume with each heartbeat. This phenomenon is most commonly associated with dilated cardiomyopathy (DCM), where the heart's ability to contract is impaired, leading to variations in stroke volume and thus influencing the pulse strength.

In the context of DCM, the weakened myocardial contractility can cause fluctuations in the blood ejected with each heartbeat, resulting in pulsus alternans. This clinical sign can be observed during physical examination and serves as an important indicator of the severity of heart failure in patients with this condition.

While the other options mention characteristics relevant to different cardiac issues, they do not specifically relate to the mechanism of pulsus alternans or its association with the inherent contractile dysfunction seen in dilated cardiomyopathy.