How can strain imaging detect subclinical LV dysfunction before a drop in EF occurs?

How can strain imaging detect subclinical LV dysfunction before a drop in EF occurs?

• A. A relative decrease in GLS (less negative) or a drop from baseline by 5% signals subclinical dysfunction
• B. An absolute decrease in EF by 20% signals subclinical dysfunction
• C. A relative decrease in GLS (less negative) or a drop from baseline by 10–15% signals subclinical dysfunction
• D. An increase in LV end-diastolic volume signals subclinical dysfunction

Answer: (C)

Strain imaging detects subclinical LV dysfunction by measuring how the heart muscle deforms during contraction, with global longitudinal strain (GLS) being especially sensitive to early changes. In a healthy heart, GLS is about −20% (the more negative, the better). When dysfunction begins, the longitudinal fibers don’t shorten as effectively, so GLS becomes less negative. A relative drop from a patient’s baseline by roughly 10–15% indicates this early impairment, even if the ejection fraction still appears normal. This lets clinicians identify injury or cardiotoxic effects before EF declines. An absolute EF decrease signals more overt dysfunction, and a rise in LV end-diastolic volume reflects remodeling rather than the initial contractile impairment detected by strain.

Strain imaging detects subclinical LV dysfunction by measuring how the heart muscle deforms during contraction, with global longitudinal strain (GLS) being especially sensitive to early changes. In a healthy heart, GLS is about −20% (the more negative, the better). When dysfunction begins, the longitudinal fibers don’t shorten as effectively, so GLS becomes less negative. A relative drop from a patient’s baseline by roughly 10–15% indicates this early impairment, even if the ejection fraction still appears normal. This lets clinicians identify injury or cardiotoxic effects before EF declines. An absolute EF decrease signals more overt dysfunction, and a rise in LV end-diastolic volume reflects remodeling rather than the initial contractile impairment detected by strain.