Preclinical Myocardial Dysfunction
Traditional imaging biomarkers may be normal in early subclinical
disease, however reduced global longitudinal strain (GLS) related to
subendocardial dysfunction is common. (Figure 1). The prevalence of
reduced GLS in asymptomatic type 2 diabetes mellitus has been reported
to range from 37% to 54% 8. Impaired longitudinal
strain may be present prior to the onset of LV remodeling and
hypertrophy 9. Furthermore, reduced longitudinal
strain may exist despite normal or near normal conventional Doppler and
tissue Doppler-derived parameters of diastolic function10(Figure 2). Compensatory subepicardial hypertrophy
may develop in an effort to reduce subendocardial wall stress and
preserve ejection fraction 11. Despite mild, resting
impairment in longitudinal mechanics, those with preclinical myocardial
dysfunction typically augment longitudinal strain to near normal values
during exercise 12. Complex interactions between
protracted risk factor exposure and progressive structural changes
influence the progression from the asymptomatic phase to symptomatic
heart failure. High risk structural findings in asymptomatic patients at
elevated risk for progression to symptomatic disease include elevated
E/e’, left ventricular hypertrophy (LVH), and abnormal
GLS12.