Progeria of the Heart in Type 1 Diabetic Children?

Diabetes mellitus (DM) itself may induce subclinical myo-cardial dysfunction without significant coronary artery disease. Accordingly, adults with type 2 DM are susceptible for heart failure and a lot of experimental studies have shown significant changes in microvasculature and myocardial interstitial fibro-sis in type 2 DM. 2-4) Therefore, early recognition of subclinical myocardial dysfunction and therapeutic intervention such as renin-angiotensin-aldosterone system blockers may prevent the progression of heart failure in diabetic patients. 3) Although there have been many studies regarding diabetic cardiomyopa-thy in adults with type 2 DM, adults subjects innately have confounding factors for subclinical myocardial dysfunction. Aging , coronary artery disease, hypertension and long-standing metabolic properties related to insulin resistance also influence on left ventricular (LV) mechanical function. In this issue of the Journal, Abd-El Aziz et al. 5) report the results of their study of forty patients with type 1 DM and forty-two healthy controls between 6 and 16 years. In this study, the interrogators demonstrated that diabetic children have evidence of LV and right ventricular dysfunction on tissue Dop-pler echocardiographic assessment. Children with type 1 DM usually have fewer confounders of myocardial dysfunction than adults with type 2 DM. In fact, only one patient in this study subjects had blood pressure above 95th percentile. We can simply accept that myocardial dysfunction in diabetic children is mainly caused by DM itself. This is one of the strengths of this study. However, in the interpretation of the present study, main results should be cautiously understood. First, in terms of LV dia-stolic function, E' velocity and E/E' were not different between diabetic children and controls. The majority of differences regarding LV diastolic function between two groups were resulted from the mitral inflow Doppler parameters, which are dependent on LV preloads. Moreover, the investigators failed to demonstrate decreased E' velocity, an early indicator of LV relaxation , in type 1 diabetic children although decreased LV and right ventricular S' velocities and increased global myocardial performance index were clearly shown. All parameters that were significantly different between two groups don't exactly indicate LV diastolic dysfunction in type 1 diabetic children. Second, we need to consider the effects of normal growth in children on tissue Doppler imaging velocities. It has been well-known that tissue Doppler imaging velocities are variable and age-dependent in children. Choi et al. 6) investigated myocardial tissue Doppler velocities in 144 healthy children (age range: 0 to 19 years) to …