Are cardiovascular reflexes more commonly impaired in patients with bronchial carcinoma?

Non-invasive tests of cardiovascular autonomic function were performed in 69 patients with histologically proved bronchial carcinoma and the results compared with those obtained in a group of age and sex matched controls. Only two patients were under 50 years of age, and with the exception of the heart rate response to deep breathing the tests performed have no accepted normal ranges in patients of this age. None of the patients had features of florid, disabling autonomic neuropathy. All the tests of autonomic function showed declining performance with age but in addition there were significant differences in the results when the two groups were compared. In the group with carcinoma the resting heart rate was higher (p less than 0.05), the resting supine blood pressure lower (p less than 0.01), and the postural fall in blood pressure greater (p less than 0.01). Test results were not related to tumour histology, the presence of finger clubbing, drug history, or symptoms suggestive of autonomic dysfunction. Abnormal responses in tests of cardiovascular autonomic function are commonly found in elderly patients but bronchial carcinoma appears to have an additional effect. The precise mechanism of this effect remains a matter for speculation.