Computer-controlled stimulator for clinical cardiac studies

Abstract

A computer-controlled stimulator is described to generate the complex stimulation patterns required for a detailed analysis of ventricular myocardial function and the responses of the conduction system to applied stimuli, Pulse interval, height and width can be generated on a beat-to-beat basis. For the safety of the patient many safeguards have been built in: a transformer in the output circuit prevents d.c. stimulation and also a leakage current of more than 500 nA, upper and lower frequency limits which are established independently of the computer by means of thumbwheel switches, and a built-in battery-powered R-wave synchronised pacemaker, which takes over the rhythm if something should go wrong. Provisions have been made to construct in the future a c1osed-loop system (patient-computer-patient)in which the computer determines the pulse sequence from the results of online data analysis.