Abnormal systolic time intervals in obesity and their relationship with the amount of overweight

We studied 17 severely obese subjects (age range 26 to 42 years), without hypertension, diabetes mellitus, angina, or clinical signs of heart failure or respiratory disease, and 16 age-matched control subjects. X-teleroentgenographic findings (transverse cardiac diameter and cardiothoracic ratio), blood pressure, and mechanocardiographic parameters were analyzed in both groups. By means of conventional simultaneous recordings of ECG, phonocardiogram, and carotid pulse (100 mm/sec), systolic time intervals were calculated as mean values from 10 beats in the morning. The following comparisons were made by means of analysis of variance: heart rate, preejection period (PEP), rate-corrected PEPI (PEPI), left ventricular ejection time (LVET), and QS2 interval (QS2); the latter two were both corrected for heart rate, respectively, as LVETI and QS2I and the PEP/LVET ratio. Abnormal x-ray data were shown in the obese group along with higher values for heart rate, PEP, PEPI, and PEP/LVET and a shorter LVETI; there were no differences in QS2I or blood pressure. There was a correlation between the amount of overweight and, respectively, transverse cardiac diameter (r = 0.84), heart rate (r = 0.69), PEP (r = 0.49), PEPI (r = 0.59), LVETI (r = -0.61), and PEP/LVET ratio (r = 0.72). A correlation was also found between transverse cardiac diameter and PEP/LVET (r = 0.67). We conclude, therefore, that abnormalities in the mechanocardiographic parameters are related to cardiac enlargement, suggesting a preclinical cardiac dysfunction secondary to chronic cardiocirculatory overload in severe obesity. Thus systolic time intervals appear to be affected by preclinical abnormalities of cardiac performance in these subjects.