Stratos LV/LV-T Technical Manual 71

In the ventricular-controlled modes, the basic interval is started by a ventricular event.

CAUTION

Programming Modifications – Extreme programming changes should only be made after careful clinical assessment. Clinical judgment should be used when programming permanent pacing rates below 40 ppm or above 100 ppm.

2.3.2 Rate Hysteresis

Rate Hysteresis can be programmed in DDD(R), DDT(R), DDT(R)/A, DDI(R), VDD(R), VDT(R), VDI(R), VVI(R), VVT(R), AAI(R) and AAT(R) modes. Hysteresis can be programmed OFF or to values as low as -50 bpm. The Hysteresis rate is based on the lower rate and the value of the programmable parameter. Hysteresis is initiated by a sensed event. The resulting Hysteresis rate is always less than the lower rate. A conflict symbol (>>) will appear and transmission will be prohibited for Hysteresis rates which are less than 30 bpm. The ability to decrease the effective lower rate through Hysteresis is intended to preserve intrinsic rhythm. The Stratos CRT-Ps operate by waiting for a sensed event throughout the effective lower rate interval (Hysteresis interval). If no sensed event occurs, a pacing pulse is emitted following the Hysteresis interval.

In DDD(R), DDT(R)/A, DDT(R), VDD(R), VDT(R), AAT(R) and AAI(R) pacing modes, the hysteresis interval starts with an atrial sense event. In DDI(R), VVI(R), VVT(R) and VDI(R) pacing modes, the hysteresis interval starts with a ventricular sense event. In DDD(R), DDT(R)/A, DDT(R), VDD(R) and VDT(R) pacing modes, the hysteresis interval also starts with ventricular extrasystoles.

NOTE:

If rate adaptation is active, the Hysteresis rate is based on the current sensor-indicated rate and the value of the programmable parameter.