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User question:
Question:
What will be the battery life of the Abbott Aveir VR leadless pacemaker implanted to a patient 70 years old with a heart rate of 50 beats per minute after implantation , patient who exercises an average of 700 minutes weekly and with the following pacemaker interrogation data test results : on the day of implantation (5/8/2024) -Capture 1.5 V @ 0.4 ms- Sense: 2.7 mv - Impedance :340 Ohms. Interrogation data 11 months later ( 4/1/2025) -Capture: 3.0 V @ 0.4 ms- Sense: 4.0 mV -Impedance 550 Ohms.Parameters: Mode VVI -Sensor: Passive- Base Rate: 50 bpm - Max Sensor rate: 130 bpm.?
Answer:
That's a really interesting question that requires careful consideration of several factors to estimate the battery life of the Abbott Aveir VR leadless pacemaker. Let's break down the information you've provided and see what we can deduce.
Here's what we know:
Pacemaker: Abbott Aveir VR leadless pacemaker
Patient Age: 70 years old
Resting Heart Rate: 50 beats per minute (base rate of the pacemaker)
Exercise: 700 minutes per week (significant activity)
Implantation Date: May 8, 2024
Initial Interrogation (May 8, 2024):
Capture Threshold: 1.5 V @ 0.4 ms
Sensing Amplitude: 2.7 mV
Impedance: 340 Ohms
Follow-up Interrogation (April 1, 2025 - approximately 11 months later):
Capture Threshold: 3.0 V @ 0.4 ms
Sensing Amplitude: 4.0 mV
Impedance: 550 Ohms
Pacemaker Parameters:
Mode: VVI (Ventricular Pacing and Sensing, Inhibited by sensed ventricular events)
Sensor: Passive (rate responsive feature is likely less active than an accelerometer-based sensor)
Base Rate: 50 bpm
Maximum Sensor Rate: 130 bpm
Analysis and Estimation:
Pacing Dependency: The VVI mode with a base rate equal to the patient's resting heart rate suggests the patient likely has intermittent or rate-dependent pacing needs. If the patient spends a significant amount of time above 50 bpm due to sinus rhythm or exercise, the pacemaker will be inhibited and consume less battery. However, with 700 minutes of weekly exercise, the pacemaker will likely pace at the base rate for a substantial portion of the remaining time.
Capture Threshold Trend: The increase in capture threshold from 1.5 V to 3.0 V over 11 months is a significant change. This indicates a potential increase in the energy required for each paced beat over time, which will negatively impact battery longevity.
Sensing Amplitude Trend: The increase in sensing amplitude from 2.7 mV to 4.0 mV is a positive trend. Higher sensing amplitudes generally mean the pacemaker has a better ability to detect the heart's intrinsic activity, potentially leading to more inhibited pacing.
Impedance Trend: The increase in impedance from 340 Ohms to 550 Ohms could suggest changes at the electrode-tissue interface. While within a typical range, a significant increase might influence current drain.
High Exercise Levels: 700 minutes of exercise per week is well above average. During exercise, the patient's heart rate will likely be above the base rate, leading to inhibition of pacing and reduced battery consumption during those periods. However, the increased demand on the heart during exercise might correlate with underlying conditions affecting the pacing threshold over time.
Passive Sensor: A passive sensor generally responds to physiological changes indirectly (e.g., changes in minute ventilation). It might not increase the pacing rate as aggressively as an activity-based sensor during exercise, potentially leading to more pacing at the base rate during the initial stages of exercise.
Estimating Battery Life:
It's impossible to give an exact battery life prediction without the specific device's battery capacity and detailed algorithms from Abbott. However, we can make some qualitative estimations based on the trends:
The increased capture threshold is the most concerning factor for battery longevity. A doubling of the voltage requirement for capture significantly increases the energy delivered per pulse.
The high level of exercise likely offsets some of this increased energy consumption by inhibiting pacing for a considerable amount of time each week.
The base rate being equal to the resting heart rate suggests that during rest and periods below exertion, the pacemaker will be actively pacing.
Considering Typical Leadless Pacemaker Longevity:
Generally, leadless pacemakers like the Abbott Aveir VR are designed to last several years. Factors influencing their lifespan include:
Pacing Output: Higher voltages and pulse widths for capture consume more energy.
Pacing Rate: A higher percentage of time spent pacing at a higher rate drains the battery faster.
Sensing Performance: Proper sensing that inhibits unnecessary pacing conserves battery.
Device Impedance: While within range, significant changes can affect current drain.
Battery Capacity: The inherent capacity of the lithium-iodide battery.
Given the observed trends, particularly the significant increase in capture threshold within the first year, the projected battery life for this patient might be on the lower end of the typical range for an Aveir VR. It's crucial for the physician to closely monitor the capture threshold at subsequent interrogations. A continued rapid increase could indicate a need for parameter adjustments if possible or suggest a shorter overall battery life than initially anticipated.
Recommendation:
The best way to get an accurate estimate of the remaining battery life is through the Abbott programmer during a device interrogation. The programmer uses proprietary algorithms based on the device's performance and historical trends to provide an estimated Remaining Battery Life (RBL) or Estimated Longevity.
In summary, while the high exercise level is likely beneficial for battery conservation due to increased intrinsic heart rate, the significant rise in capture threshold in the first 11 months suggests that the battery life for this specific patient might be shorter than average. Regular and close monitoring of the device parameters is essential.