Diabetes, Vol 43, Issue 4 607-612, Copyright © 1994 by American Diabetes Association
The squatting test. A useful tool to assess both parasympathetic and sympathetic involvement of the cardiovascular autonomic neuropathy in diabetes
R Marfella, D Giugliano, G di Maro, R Acampora, R Giunta and F D'Onofrio
Department of Gerontology and Metabolic Diseases, Second University of Naples, Italy.
The heart rate responses observed after both squatting and standing are
thought to be of reflex nature and may be useful to assess the functional
integrity of parasympathetic and sympathetic nerves in diabetes. In the
standard maneuver, each subject stood still for 3 min, then squatted down
for 1 min, and at last stood up during an inspiratory phase. In 10 healthy
subjects (25-31 years of age), lengthening of the R-R interval during
squatting was abolished by atropine, whereas propranolol markedly
attenuated shortening of the R-R interval at standing from squatting.
Squatting test (SqT) ratios (SqT vagal [SqTv] = ratio between the R-R
interval mean before squatting and the longest R-R interval after
squatting; SqT sympathetic [SqTs] = ratio between the basal R-R interval
and the shortest R-R interval at standing) were calculated in 558 healthy
subjects and 346 diabetic patients (insulin-dependent diabetes
mellitus/non-insulin-dependent diabetes mellitus: 103/243). Normal ranges
(95 and 99% confidence intervals [CIs]) for subjects 20-74 years of age
showed a statistically significant negative correlation with age. SqTv was
outside the 99% CI in 145 (42%) diabetic patients and in 7 (1.3%) of the
control subjects. The corresponding figures for SqTs were 40 and 0.8%,
respectively. Age and duration of diabetes had a negative influence on SqT
ratios. SqT ratios were compared with other reflex tests currently used for
diagnosis of autonomic neuropathy: deep breathing (DB), lying-to-standing
(LS), Valsalva manuever, and blood pressure change after standing
(orthostatic hypotension [OH]).(ABSTRACT TRUNCATED AT 250 WORDS)