[Measurement of coefficient of variation of R-R interval in ECG for patients with impotence].

The coefficient of variation (CV = SD/mean x 100) of the R-R interval in electrocardiogram (ECG) was measured as an indication of parasympathetic nerve function in patients with impotence. Of 762 patients 104 (13.6%) had a CV value lower than 2.0. The factors which led to the low CV value were evident in 50 patients (48%), i.e. diabetes mellitus in 26, side effects by antiulcer, antidepressant or antihypertensive agent in 16, renal failure in 1, alcoholism in 2 and age over 70 years old in 4. The possible factors of the low CV value, such as neurogenic, thyroid, cardiovascular and endocrine disorders were found in 12 patients (11.5%). In the remaining 42 patients (40.4%), CV value was decreased by unknown factors. Measurement of CV of R-R interval in ECG was safe and useful as a screening test for patients with impotence to detect the dysfunction of the parasympathetic nerve system.