Left Ventricular Diastolic Dysfunction in Asymptomatic Type 2 Diabetic Patients: Detection and Evaluation by Tissue Doppler Imaging

CONFLICT OF INTEREST: NONE DECLARED The aim of the study was detection of diastolic dysfunction of myocardium with Tissue Doppler Imaging (TDI) in asymptomatic type 2 diabetic patients, in five years duration of disease, and normal cardiac function on conventional echocardiography (CE), according to the performance showed on exercise stress test. MATERIAL AND METHODS: We studied 300 patients, of them 150 patients with non-obese, normotensive, uncomplicated type 2 diabetes, in five years duration of disease and 150 healthy control subjects. Of all patients, 100 with type 2 diabetes, and 100 patients from the control group underwent exercise test on a treadmill. All participants underwent both CE and TDI echocardiography. With TDI, lateral E’ peak velocity, atrial velocity (A’), their ratio (E’/A’) and systolic velocity (S’) were measured. Diastolic dysfunction was diagnosed by tissue Doppler imaging, and the following criterion was met: E’/A’ ratio <1. Cardiac function with CE was without significant features in the two groups. RESULTS AND DISCUSSION: Using TDI interrogation, diabetic subjects showed a lower E’ velocity (10,75±1,2 vs. 14±3 cm/s, p<0,001), an increased A’ velocity (10,65±1,8 vs. 11±3 cm/s, p<0,02), and a reduced E/A ratio (0,82±0,04 vs. 1,17±1,4, p<0,001), S (8.92±3,80 vs. 9,30±3.30 cm/sec); E/A (1,17±0.55, p<0,01). In diabetic patients, after the exercise stress test performance, the myocardial velocity increase is registered for wave E’=1,27 cm/sec (12,01%), for wave A’=1,7 cm/sec (15,9%), reduced ratio E’/A’ (0.89±0,1 cm/sec 9,0%) and S’=1,3 cm/sec (14,77%). Whereas, mean myocardial velocity values in examined control group after the exercise stress test were higher as follows: E’=2,7 cm/sec (19%), A’=2,1 cm/sec (14%), E’/A’=0,8 cm/sec (12%), and S’=2,7 cm/sec (18%). Myocardial diastolic dysfunction due to reduced exercise tolerance can be evidenced by TDI in type 2 diabetic subjects, even in the presence of a normal cardiac function with CE and symptom free diabetic patients in rest. Therefore, our findings could justify the use of Tissue Doppler imaging for diastolic function assessment in diabetics with otherwise non significant features on CE.