Biotronik
Blended sensors
CLS (closed loop stimulation)
Accelerometer
RR - CLS
CLS measures the intracardiac impedance throughout EACH ventricular contraction.
During the “resting state” (monitored by accelerometer) the impedance values will establish a continuously updated reference curve, which reflects the contraction dynamics at rest.
With each heartbeat, CLS determines the impedance waveform during the ventricular contraction and compares it to its reference waveform at rest.
Slight changes between the reference curve and the next load curve will result in a minimum change in rate adaptation.
Moderate changes between the reference curve and the next load curve will result in a moderate increase in heart rate
Large changes between the reference curve and the next load curve will result in heart rate adaptation up to the maximum CLS rate.
CLS programming
Accessed from Parameters; Bradycardia
•Mode: [DDD-CLS] or [VVI-CLS]
•[CLS] CLS rate: 85% of 100% max HR
•[CLS- Expert Options]
•CLS Response (slope): very low, low, medium, high, very high
•Resting Rate Control: off, +10, +20, +30, +40, +50
•V pace required: yes, no
For non-syncopal patients, program resting rate control to +20. Thus when the accelerometer detects patient is at rest, HR will only increase by 20bpm.
For syncopal patients, program resting rate to off. Thus accelerometer will increase to max HR. Moreover, program CLS response to high so that these patients get a quick response.
RR - Accelerometer
Sensor Gain
•The programmable sensor gain designates the factor by which the electric signal of the sensor is amplified
•This allows the rate adaptation to be modified for individually variable signal strengths
•The optimal setting is achieved when the desired maximum sensor rate is reached during maximum exertion
•Before adjusting the sensor gain, the rate increase, rate decrease and maximum sensor rate parameters must be checked for their suitability with respect to the individual patient
Automatic Sensor Gain
•The programmable sensor gain is supplemented by the automatic sensor gain function
•Everyday. The device checks whether 90% of the set maximum sensor rate has been reached for a certain total duration (for atleast 90 seconds (cumulative) within one day)
•If 90% of the set maximum sensor rate is reached, the sensor gain decrease by one increment
•If 90% of the set maximum sensor rate has not been reached within 7 days, the sensor gain increase by one increment
Sensor threshold
•The minimal signal strength used for rate adaptation is determined using the programmable sensor threshold.
•Sensor signals below this threshold do not affect rate adaptation.
•With the sensor threshold, a stable rate can be achieved when the patient is at rest by ignoring low amplitude signals that have no relevance for increased levels of physical exertion
•If the pacing rate at rest is unstable or reached values that are above the basic rate, the senor threshold should be increased.
•On the other hand, the sensor threshold should be reduced if a sufficient rate adaptation is not observed with slight exertion
•The sensor gain should be adjusted before setting the sensor threshold
Rate increase
•The programmed rate increase value determined the maximum speed at which the pacing rate rises if the sensor signal indicates increasing exertion
•A setting of the rate omcrease of 2 bpm per cycle
•For example; if the rate increases from 60 bpm to 150 bpm in 45 cycles
•The programmed rate increase applies only to the rate analysed by the sensor
Rate decrease
•The programmed rate decreased value determines the maximum speed by which pacing is reduced if the sensor signal begins decreasing
•A setting for rate decrease if 0.5 bpm per cycle
•For example, means that a rate of 150 bpm will fall to 60 bpm within 180 cycles
•Note: in DDIR mode, the actual rate decrease is sometimes slower, depending partly on the programmed AV delay
Sensor Simulation
•Even when a non rate adaptive mode is programmed, the sensore response is recorded without being effective.
•As a result, when rate adaptation is activated there will already be data according to which the sesor response can be evaluated in the histogram
Rate Fading
•In all pacing modes the rate smoothing/fading function in case of sudden rare decreases, lead to a controlled adjustment of the pacing mode of the device to the patients intrinsic rhythm,. To the programmed basic rate or to the sensor rate
•If rate smoothing is activated, the device calculates the backup rate, which is always active in the background.
•When a sudden decrease of the heart rate occurs, the device immediately beings to pace at the backup rate and regulated the process of rate decrease guided by the backup rate and the rate fading settings
RR - dynamic AV delay
Accessed from Parameters; Bradycardia;
•AV Hysteresis: OFF, low, medium, high, fixed, individual
•Optional rate-responsive AV delays. Thus with faster rates, AV delay will shorten.
Low: 180-140
Medium: 180-100
High: 180-75
Fixed: one AV delay
Individual: upper and lower AV delays programmable
RR - auto PVARP
RR - auto PVARP