Asystolic episodes during pacemaker implantation.
During normal rate programming of a pulse generator from slower to more rapid rates, intervals of output impulse suppression lasting 2 seconds plus the newly programmed interval to a maximum of 3.935 seconds are possible, and are a result of the pulse interval control system. These occur if programming falls within the susceptible window (the period between the existing interval and the new one) but will not take place if the programming command is given immediately after an output pulse. Four incidents with resulting ventricular asystole of up to 2.8 seconds are documented and explained. No significant clinical complications were observed.