Central adiposity and left ventricular mass in obese children

AIM

The impact of central adiposity on left ventricular (LV) mass in childhood obesity has been little explored. This study evaluates whether central obesity influences LV mass and function in obese children.

METHODS AND RESULTS

Biochemical, anthropometric and echocardiographic measurements were taken in obese (n=111, mean age 10.6+/-2.5 years) and non-obese children (n=30, mean age 10.8+/-3.0 years). Left ventricular function was analyzed by conventional and tissue Doppler echocardiography. LV mass was calculated according to the Penn convention and indexed for height(2.7) (LVM(i)). The obese group showed increased levels of LVM(i) as compared to the non-obese group (35.7+/-8.5 vs 23.5+/-2.8 g/h(2.7), p<0.0001). Among obese children, we observed a significant increase of LVM(i) across tertile of waist-height ratio (WHtR). The subjects identified by the highest tertile of WHtR, as compared to subjects identified by the lowest tertile, showed higher levels of BMI (29.5+/-5.4 vs 31.0+/-5.0 kg/m(2), p<0.0001) and LVM(i) (32.1+/-6.5 vs 37.1+/-8.5 g/h(2.7), p<0.01). Among obese children a positive correlation (standardized for age and gender) was found between LVM(i) and BMI (r=0.282, p<0.01) and WHtR (r=0.334, p<0.0001). To analyze the independent predictors of LVM(i), a stepwise linear regression analysis was performed using age, gender, BMI, blood pressure, heart rate, HOMA-IR and WHtR as independent variables. LVM(i) was independently associated only with WHtR (beta=0.309, t=3.238, p=0.002).

CONCLUSION

Obese children show an increased LVM(i) and a preserved LV function. Central adiposity is the major determinant of left ventricular mass.

Early detection of diabetic cardiomyopathy: usefulness of tissue Doppler imaging

OBJECTIVE

The aim of the study was to evaluate whether tissue Doppler imaging (TDI) detects a pre-clinical impairment of diastolic function in subjects with Type 2 diabetes with short duration of disease and normal cardiac function with conventional echocardiography (CE), and whether echocardiographic parameters are related to metabolic abnormalities.

PATIENTS AND METHODS

We studied 40 non-obese, normotensive, uncomplicated Type 2 diabetic subjects with short duration of disease and 20 control subjects. All participants underwent both CE and TDI echocardiography. With TDI, early velocity (Ea), atrial velocity (Aa), their ratio (Ea/Aa) and systolic velocity (Sa) were measured at the lateral corner of mitral annulus. Glycosylated haemoglobin, fasting plasma glucose and insulin were determined and homeostasis model assessment (HOMA-IR), as an index of insulin resistance, was calculated.

RESULTS

Cardiac function with CE was similar in the two groups. Using TDI, diabetic subjects showed a lower Ea velocity (15.5+/-3.9 vs. 19.4+/-3.5 cm/s, P<0.0001), an increased Aa velocity (15.5+/-2.4 vs. 14.1+/-2.4 cm/s, P<0.05) and a reduced Ea/Aa ratio (1.00+/-0.2 vs. 1.39+/-0.3, P<0.0001), compared with control subjects. Linear regression analysis in the diabetic group showed that only HOMA-IR was negatively associated with Ea/Aa ratio (P=0.026). No significant association was observed with other metabolic variables.

CONCLUSION

An early stage of diabetic cardiomyopathy can be evidenced by TDI in Type 2 diabetic subjects even in the presence of a normal cardiac function with CE. This abnormality is associated with insulin resistance.

[Identification of patients with acute myocardial infarction that may be discharged early: prospective evaluation with simple clinical and instrumental indicators]

BACKGROUND

The hospital stay for "uncomplicated" acute myocardial infarction (AMI) is often too long. A reduction in the length of hospitalization, if proven to be safe, is advantageous in terms of costs and health organization. Accordingly the aims of the present, prospective study, were to evaluate: 1) the patients with AMI eligible for early discharge; 2) the incidence of adverse cardiovascular events within 2 weeks of myocardial infarction; 3) the incidence of cardiovascular mortality at 6-month follow-up.

METHODS

On the fifth day after AMI, 331 of 526 patients, consecutively admitted to our coronary care unit between March 1997 and August 1999, were assigned to "complicated" and "uncomplicated" AMI groups, according to clinical and non-invasive criteria. Uncomplicated myocardial infarction eligible for early discharge was defined in patients < 75 years, as the absence of a high risk personality, stroke, left bundle branch block, transient myocardial ischemia after the first 24 hours from AMI, clinical signs or echocardiographic evidence of left ventricular dysfunction (ejection fraction < 40%), ventricular fibrillation, sustained ventricular tachycardia, symptomatic bradyarrhythmias after the first 48 hours from AMI, cardioversion or defibrillation (after the first 48 hours) or the need for coronary angioplasty or coronary artery bypass grafting. Uncomplicated patients were discharged on the sixth day after AMI (hospital stay 6.5+/-0.72 days). A symptom-limited ergometric stress test was planned in the uncomplicated group 14 days after AMI. "Hard" (death, reinfarction) and "non-hard" (unstable angina, myocardial revascularization) adverse cardiovascular events were monitored at 2 weeks of follow-up, and cardiovascular mortality at 6-month follow-up.

RESULTS

Four (1.2%) hard (0.3% exitus and 0.9% reinfarction) and 7 (2.1%) non-hard adverse events occurred among patients with uncomplicated AMI at 2 weeks of follow-up. Patients with uncomplicated AMI who developed adverse events, presented during the primary coronary event creatine kinase (CK) and CK-MB serum levels which were significantly lower than those observed in patients who did not present adverse events. In the complicated group (hospital stay 9.9+/-1.79 days), from day 6 to 14 after AMI, 65 (33%) hard and non-hard events occurred. A significant reduction in mortality between the uncomplicated and complicated group (2.11 vs 27.17%, p < 0.0001) was observed at 6-month follow-up. Multivariate analysis showed a statistically significant difference for age and thrombolytic treatment.

CONCLUSIONS

This first Italian prospective study demonstrated the possibility of identifying, 5 days after AMI and on the basis of simple criteria and without a stress test, a low risk population of patients eligible for early discharge.