Impact of body mass index on markers of left ventricular thickness and mass calculation: results of a pilot analysis

Specific correlations between body mass index (BMI) and left ventricular (LV) thickness have been conflicting. Accordingly, we investigated if a particular correlation exists between BMI and echocardiographic markers of ventricular function. METHODS: A total of 122 patients, referred for routine transthoracic echocardiography, were included in this prospective pilot study using a 3:1 randomization approach. Patient demographics were obtained using a questionnaire. RESULTS: Group I consisted of 80 obese (BMI was >30 kg/m2), Group II of 16 overweight (BMI between 26 and 29 kg/m2), and Group III of 26 normal BMI (BMI < 25 kg/m2) individuals. No difference was found in left ventricular wall thickness, LV end-systolic cavity dimension, fractional shortening (FS), or pulmonary artery systolic pressure (PASP) among the groups. However, mean LV end-diastolic cavity dimension was greater in Group I (5.0 +/- 0.9 cm) than Group II (4.6 +/- 0.8 cm) or Group III (4.4 +/- 0.9 cm; P < 0.006). LV mass indexed to height(2.7) was also significantly larger in Group I (61 +/- 21) when compared to Group III (48 +/- 19; P < 0.001). Finally, left atrial diameter (4.3 +/- 0.7 cm) was also larger (3.8 +/- 0.6 and 3.6 +/- 0.7, respectively; P < 0.00001). DISCUSSION: We found no correlation between BMI and LV wall thickness, FS, or PASP despite the high prevalence of diabetes and hypertension in obese individuals. However, obese individuals had an increased LV end-diastolic cavity dimension, LV mass/height(2.7), and left atrial diameter. These findings could represent early markers in the sequence of cardiac events occurring with obesity. A larger prospective study is needed to further define the sequence of cardiac abnormalities occurring with increasing BMI.