Cardiac autonomic function in obese patients.
OBJECTIVE: The aim of this work was to determine the presence and prevalence of alterations in cardiac autonomic function in obese, non-diabetic subjects. SUBJECTS: These were 121 obese people, 15 with glucose intolerance and none with diabetes, and a group of 40 healthy people. MEASUREMENTS: A series of five standardized tests was carried out, three of which were based mainly on parasympathetic control (heart rate response to Valsalva, deep breathing and lying-to-standing) and two on cardiovascular sympathetic function (blood pressure response to standing and to handgrip). RESULTS: The response to the deep breathing test correlated negatively with age, as it did in control subjects. At least one parasympathetic test, age-adjusted, was abnormal in 49 patients (40.5%). Five other patients had an abnormal handgrip test, and no patient had orthostatic hypotension. No correlation was found between the parasympathetic test results and sex or body mass index. Prevalence of cardiac autonomic dysfunction, considered to be present when at least one parasympathetic test was abnormal, did not differ according to a gynoid or android type of obesity. A significant negative correlation was found between heart rate response to deep breathing and fasting glycemia. CONCLUSION: It was concluded that cardiac autonomic dysfunction evidenced by means of simple, reliable, reproducible tests is frequent in the non-diabetic obese subject. This disorder could explain the poor cardiovascular prognosis associated with obesity. Whether it is a complication of obesity or a marker associated with certain kinds of obesity (of hypothalamic origin) remains to be clarified.