FIRST EXPERIENCE OF THE USE OF CARDIAC-PA CEMAKERS WITH AUTOMATED-DETERMINATION OF THE STIMULATION THRESHOLD

The aim of this study conducted on 7 patients with implanted REGENCY S R+ and MICRONY SR+ pacemakers was to evaluate function of automatic de termination of the stimulation threshold. Automatic and manual thresho ld measurements were performed in the postoperative period. Sensitivit y to R-wave and to captured QRS complex, and stimulus amplitude were a lso determined. Results of manual and automatic measurements were almo st identical and indicative of the reliability of automatic determinat ion of the stimulation threshold. There were no long periods of ineffe ctive pacing. If a stimulus caused no response another stimulus was ap plied with amplitude of 4,5 V. Such a situation could arise in the pre sence of fusion complexes, Thus when maximal stimulus amplitude is obt ained at automatic control of the pacing threshold one should conduct an analysis taking into consideration possible causes of this finding. Fluctuations of sensitivity to captured ventricular complex was obser ved during first months after pacemaker implantation. Therefore determ ination of sensitivity is advisable at each testing of a pacemaker.