Response time and heart rate in coronary patients under mild mental stress

A mild mental stress was applied on 39 normal people and on 33 patients with coronary artery disease. The test consisted in their selecting the proper switch out of 2, in order to switch off a lamp out of 3 as soon as possible after its ignition. The 3 lamps were lit by the examiner in a stereotyped random sequence. No consequences were implied against the subjects in case of failure and this was clearly explained to them. The response time of the people was recorded together with their electrocardiogram in a one-channel recorder using a suitable circuitry. The study showed that the response time became progressively shorter during the test only in the coronary group, although the mean value did not differ significantly from that in the normal group. The R-R interval was shortened in both groups but in the coronary group significantly more so than in the normal group. Pretreatment with diazepam reversed both responses of the coronary group. Pretreatment with propranolol mitigated the tachycardiac effect of the test in the coronary group, reversed its effect in the normal group and shortened the response time significantly in the normal group. The objective time measurements by the device used might suggest that in patients with coronary artery disease both the specific (response time) and the nonspecific (R-R interval) behaviour in response to a mental stress differ from that in normal people. This behaviour may be modified by medicaments like diazepam and propranolol.