Abbott pacemakers in 20 points
Content
1) Case volume
Single chamber: 10.4 cm3 (Assurity MRI model PM1272)
Double chamber: 10.4 cm3 (Assurity MRI model PM2272)
2) Battery type
Vanadium oxide lithium/silver battery
3) Wear and length criteria
2 charts :
- Gauge diagram
- Curve showing decrease in battery voltage
Values expressed: battery voltage and estimated service life
ERI operation (2.60V):
- Stimulation interval increased by 100ms
- Sensor set to Off
- NIPS and AF Suppression™ programmed on Off
The programmer displays an alert indicating that the device has detected ERI.
4) Magnet Frequency
Start of life: 100 min-1
ERI: 85 min-1
End of life: 80.7 min-1
2 possible settings for magnet response:
- Battery test (nominal)
- Off: no response to magnet
5) Traditional stimulation modes
All traditional modes are available.
6) Special mode for spontaneous conduction: VIP
Ventricular intrinsic preference (VIP™) corresponds to AV delay hysteresis. The VIP allows no blocked P waves in the presence of a paroxysmal or permanent AVB. Ventricular pacing always occurs at the end of the extended AV delay, in the absence of a spontaneous event.
The maximum programmed AV delay plus the largest extension value allows an AV delay of up to 450 ms.
7) MRI mode
Programmable modes: AOO / VOO / DOO / Stimulation Off
Frequency: 85 min-1 ; amplitude: 5 V/1 ms ; AV delay: 120ms ; bipolar stimulation
Activation and deactivation possible with programmer or activator applied to box
No exclusion zone
8) Ventricular stimulation: Autocapture
The AutoCapture™ system provides cycle-by-cycle confirmation of ventricular capture based on evoked response analysis with backup pacing at 5 V on loss of capture. The threshold is systematically measured every 8 or 24 hours. Amplitude is automatically adapted with a 0.25 V margin for the programmed pulse duration.
9) Atrial stimulation: ACap Confirm
The device measures the atrial pacing threshold every 8 or 24 hours, depending on the setting of the Search Interval parameter.
To use the ACap Confirm function, you need to implant a bipolar, low-polarization pacing lead and set the atrial pacing mode to Bipolar. A fully automatic configuration test precedes each threshold measurement. The algorithm works regardless of pacing pulse duration. Capture control is based on analysis of the morphology of the atrial evoked response at the time of threshold measurement, but without monitoring or cycle-by-cycle verification of capture thereafter. Atrial evoked response detection is unipolar, regardless of whether the detection configuration is programmed for unipolar or bipolar mode. The device memorizes the morphology of the capture failure. The safety margin varies according to the threshold: if threshold ≤ 1.5V, margin at + 1.0V; if threshold between 1.625V and 2.25V, margin at + 1.5V; if threshold between 2.375V and 3.0V, margin at + 2.0V; if threshold > 3V, amplitude at 5V.
10) Sensitivity and detection
With bipolar detection, atrial and ventricular sensitivity can be set to automatic or fixed. On the other hand, sensitivity is fixed if detection is unipolar.
When the probe is coded as bipolar, unipolar detection can be programmed either between the distal end and the housing, or between the ring and the housing.
Various parameters can be programmed to optimize the quality of bipolar detection: maximum sensitivity, adaptation delay (post-stimulation and post-detection), adaptation level (post-stimulation and post-detection) and stimulated and detected refractory period (post-stimulation and post-detection).
11) Refractory periods
Ventricular blanking after atrial pacing can be set to Auto or to a fixed value between 12 and 52 ms. If a ventricular signal is detected within the safety window (starting after ventricular blanking post atrial pacing and ending 64 ms after atrial pacing), ventricular pacing is triggered 120 ms after atrial pacing. After ventricular pacing or sensing, there is a programmable ventricular refractory period.
After atrial pacing or detection, there is a programmable atrial refractory period.
Following ventricular stimulation or detection, there is a programmable post ventricular atrial blanking.
The PVARP is programmable, with the possibility of programming a dynamic PVARP that adapts the PVARP value to the heart rate.
12) Diagnosis and interruption of pacemaker mediated tachycardias
If the algorithm detects eight consecutive AS-AS intervals above the PMT Detection Frequency, the device calculates the stability of the eight VP-AS intervals. If it determines that the VP-AS intervals are stable, for the ninth interval the algorithm modulates the AV delay by 50 ms. If the tenth VP-AS interval is similar to the previous nine, the device concludes that an PMT is present. The device then suspends ventricular pacing and delivers an atrial pulse 330 ms after the detected retrograde P wave, then resumes normal pacing.
13) Pacemaker dependency
Frequency servoing is based on data supplied by an accelerometer with various parameters programmable manually or automatically (threshold, slope, response time, recovery time, max. sensor frequency).
14) Mode switch for atrial arrhythmias
Automatic mode switching (AMS) takes place when the atrial frequency exceeds the atrial tachycardia detection frequency (ATDF).
AMS uses a filtered, rather than instantaneous, atrial rate, based on a comparison of the current atrial rate with a continuously updated average rate, in order to distinguish between sustained tachycardia and rapid intermittent cycles.
When the filtered atrial rate exceeds the programmed ATDF value, the device stops atrial rate synchronization and switches to DDI(R) or VVI(R) mode.
At each cycle, the device measures the instantaneous PP interval.
It calculates a filtered atrial interval (FAI) according to the following rule:
If instantaneous PP ≤ FAI: FAI decremented by 38 ms
If instantaneous PP > FAI: FAI incremented by 25 ms
As soon as FAI falls below ATDF: modeswitch
During mode switching, the stimulation frequency is the AMS base frequency (programmable independently of the base frequency) or the frequency indicated by the sensor.
Return to synchronous mode is only possible if the filtered atrial frequency falls below the max. synchronous frequency (FAI < max. synchronous frequency interval).
15) Flutter management
No specific algorithm; when a 2/1 flutter occurs, it is necessary to shorten the duration of post-ventricular atrial blanking.
16) Atrial arrhythmia prevention
1 algorithm is available
AF Suppression: increase pacing frequency to “overdrive” spontaneous atrial activation.
17) Wireless communication
Technology available on current platforms – RF link opens up possibilities for telecardiogy (Assurity MRI)
18) Memory duration
Maximum EGM recording time: 14 minutes
Triggers: Atrial episode (AMS input); High ventricular frequency; Consecutive PVC; AMS episode; Advanced hysteresis; Noise reversion; Magnet response
Prioritization of EGMs
19) Telemonitoring
The remote monitoring system set up with Merlin@Home and the Merlin.net network enables patient-initiated transmissions, automatic transmissions on dates programmed by the doctor, or at defined intervals, and transmissions in connection with an alert (configurable). A 30-second real-time EGM is associated with each transmission.
20) Other features
- the Negative AV Hysteresis + Search parameter enables the device to reduce the Paced AV Delay and the Sensed AV Delay when an R wave is detected, in order to prevent intrinsic conduction and favor ventricular pacing (optimize the gradient in the HCM).
- Leadless ECG
- Unfiltered and filtered EGM (Ampli Detect)
- CoreVue congestion monitor
- automatic AV Delay optimization with QuickOpt
