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• Uncomplicated obesity: more functional than morphological cardiac changes
  Gianluca Iacobellis
  Published on: 7 October 2003

• Published on: 7 October 2003

  Uncomplicated obesity: more functional than morphological cardiac changes

  • Gianluca Iacobellis, MD, PhD

  Dear Editor

  I read the recent paper by Pascual et al.[1] with interest and have some comments. They found that subclinical left ventricular diastolic dysfunction occurs in all grades of “isolated” obesity and is associated with an increased systolic function only in the early stages of obesity.

  These findings are substantially consistent with previous reports.[2- 5] Appreciating their accuracy...

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  Dear Editor

  I read the recent paper by Pascual et al.[1] with interest and have some comments. They found that subclinical left ventricular diastolic dysfunction occurs in all grades of “isolated” obesity and is associated with an increased systolic function only in the early stages of obesity.

  These findings are substantially consistent with previous reports.[2- 5] Appreciating their accuracy in describing diastolic function I would like to discuss some issues on systolic function evaluation and results interpretation. In addition, some limitations on the study design should be enhanced. The authors include subjects with BMI between 25–29.9 kg/m², really classified as overweight and not obese subjects. They correctly enrolled in this study subjects with “isolated” obesity, meaning uncomplicated obesity, in order to avoid confounding factors on cardiac parameters evaluation. Nevertheless, the presence of impaired glucose tolerance was not estimated and no data on the duration of obesity and body fat distribution were provided. Finally, they calculated left ventricular diameters and relative wall thickness, but no data on left ventricular mass and geometry were reported. In spite of the lacking of these crucial parameters, they concluded that obesity is associated with eccentric hypertrophy, structural changes and that a specific cardiomyopathy occurs in all obese individuals.

  I have performed an investigation on the influence of only excess fat on cardiac morphology and function.[2] That study showed the obesity per se, although a long duration of disease, in absence of glucose intolerance, diabetes, hypertension and dyslipidemia, is associated only with an impairment of diastolic function and hyperkinetic systole and not with left ventricular hypertrophy. Uncomplicated obese subjects present left atrium and aortic root enlargement as consequences of impaired diastole and hyperdinamic systole. Hyperkinetic systole, estimated by both endocardial and midwall parameters, seems to be due to the increased cardiac work necessary to supply a high oxygen consumption for the large body surface of obese subjects. My preliminary data on extreme obesity show that systolic function, at the rest, remains hyperdinamic and effective also in obese subjects with BMI >50 kg/m². I agree with Pascual that an increase of preload, probably partially due also to hyperinsulinemia and its sodium retentive action, could lead to the development of left ventricle eccentricity. Nevertheless, no left ventricular hypertrophy occurs in uncomplicated obese subjects. However, insulin resistance seems to be a determinant of left ventricular mass stronger than BMI.[6] Finally, to better address the relationship between central obesity and cardiac parameters, I suggest to use echocardiographic epicardial adipose tissue, as easy and reliable index of visceral fat deposition. [7-8]

  References

  (1) M Pascual, DA Pascual, F Soria, T Vicente, AM Hernández, FJ Tébar, M Valdés. Effects of isolated obesity on systolic and diastolic left ventricular function Heart 2003;89:1152–1156.

  (2) Iacobellis G, Ribaudo MC, Leto G, Zappaterreno A, Di Mario U, Leonetti F. Influence of excess fat on cardiac morphology and function: study in uncomplicated obesity. Obes Res 2002;10:767-773.

  (3) Stoddard MF, Tseuda K, Thomas M, Dillon S, Kupersmith J. The influence of obesity on left ventricular filling and systolic function. Am Heart J 1992;124:694-699.

  (4) Alpert MA, Lambert CR, Terry BE, Cohen MV, Mukerji V, Massey CV, Hashimi MW, Panayiotou H. Influence of left ventricular mass on left ventricular diastolic filling in normotensive morbid obesity. Am Heart J 1995;130:1068-73.

  (5) Alpert MA, Lambert CR, Terry BE, Cohen MV, Mukerji V, Massey CV, Hashimi MW, Panayiotou H. Interrelationship of left ventricular mass, systolic function and diastolic filling in normotensive morbidly obese patients. Int J Obes Relat Metab Disord 1995;19:550-7.

  (6) Iacobellis G, Ribaudo MC, Zappaterreno A, Vecci E, Tiberti C, Di Mario U, Leonetti F. Relationship of insulin sensitivity and left ventricular mass in uncomplicated obesity. Obes Res 2003;11:518-524.

  (7) Iacobellis G, Assael F, Ribaudo MC, Zappaterreno A, Alessi G, Di Mario U, Leonetti F. Epicardial fat from echocardiography: a new method for visceral adipose tissue prediction. Obes Res 2003; 11:304-310.

  (8) Iacobellis G, Assael F, Ribaudo MC, Zappaterreno A, Vecci E, Tiberti C Di Mario U, Leonetti F. Echocardiographic epicardial adipose tissue is related to anthropometric and clinical parameters of metabolic syndrome. A new indicator of cardiovascular risk. J Clin Endocrinol Metab 2003;88:11 November; in press.

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  Conflict of Interest:
  None declared.

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