Dobutamine Stress Echocardiography Unmasks Early Left Ventricular Dysfunction in Asymptomatic Patients with Uncomplicated Type 2 Diabetes: A Comprehensive Two-Dimensional Speckle-Tracking Imaging Study

Background: Discrepancies are present in the literature on resting myocardial mechanics in patients with uncomplicated type 2 diabetes mellitus (T2DM). Data are noticeably sparse regarding circumferential function and torsional mechanics. Resting deformation imaging may not be sensitive enough to detect subtle dysfunctions. The aim of this study was thus to comprehensively evaluate myocardial mechanics in patients with T2DM at rest and to investigate whether dobutamine stress echocardiography could unmask functional alterations that would remain otherwise subtle at rest. Methods: Forty-four patients with T2DM and 35 healthy control subjects of similar age and sex were prospectively recruited. After conventional echocardiography, myocardial mechanics was evaluated at rest and during low-dose dobutamine stress echocardiography (target heart rate, 110 beats/min). Results: Patients with T2DM presented with altered global diastolic function but preserved systolic function. Deformation imaging indexes were similar between groups at rest, but significant differences were noticed under dobutamine infusion for longitudinal strain (-21.2 +/- 2.4% vs -24.2 +/- 2.5%, P < .001), circumferential strain (apex, -32.3 +/- 5.3% vs -36.3 +/- 5.3%, P = .002; papillary muscle, -25.6 +/- 3.2% vs -28.0 +/- 3.6%, P = .001; base, -23.2 +/- 3.6% vs -25.3 +/- 3.8%, P = .03), apical (11.2 +/- 4.4 degrees vs 14.1 +/- 6.3 degrees, P = .020) and basal (-12.2 +/- 3.3 degrees vs -14.3 +/- 3.9 degrees, P = .021) rotation, and twist (21.9 +/- 5.9 degrees vs 26.8 +/- 8.3 degrees, P = .007). Multivariate analysis identified epicardial fat, dyslipidemia, and fasting glycaemia as significant contributors to the changes from rest to dobutamine. Conclusions: These findings demonstrate the usefulness of dobutamine stress echocardiography in establishing impairments in myocardial mechanics in patients with uncomplicated T2DM. Systemic metabolic disturbances and epicardial fat act as the main contributors to the blunted response to dobutamine stress in these patients.