Diastolic dysfunction in patients with type 2 diabetes mellitus: is it really the first marker of diabetic cardiomyopathy?

BACKGROUND: Diastolic dysfunction is considered the first marker of diabetic cardiomyopathy. However, preclinical systolic alteration was also recently described by strain, but its association with diastolic dysfunction has never been investigated.
METHODS: One hundred fourteen patients with type 2 diabetes mellitus (DM) with controlled blood pressure and without overt heart disease were prospectively enrolled and compared with 88 age-matched controls. All subjects underwent comprehensive echocardiography, including diastolic evaluation according to current recommendations and speckle-tracking imaging. The prevalence of diastolic dysfunction, the determinants of diastolic parameters, and the association between preclinical systolic and diastolic dysfunctions were studied.
RESULTS: Diastolic parameters were altered in patients compared with controls, with lower E/A ratios, longer mitral deceleration and isovolumic relaxation times, and higher E/e' ratio. Diastolic dysfunction occurred in 47% of patients with DM (33% and 14% with grade I and II diastolic dysfunction, respectively) and systolic alteration (longitudinal strain ≥ -18%) in 32% of patients. Whereas longitudinal systolic strain was independently associated with DM and gender, diastolic parameters were influenced by many factors, including age, rate-pressure product, history of hypertension, and body mass index. Systolic alteration occurred in 28% of patients with DM with normal diastolic function and in 35% with diastolic dysfunction.
CONCLUSIONS: Diastolic dysfunction diagnosed according to current recommendations is frequent in patients with DM but is also influenced by other factors. Systolic strain alteration may exist despite normal diastolic function, indicating that diastolic dysfunction should not be considered the first marker of a preclinical form of diabetic cardiomyopathy.