SIC (Sensed Impedance Changer) counter > 300

I finally found the reason why the doctor thought my father's pacemaker may have lead issue with 300+ short V-V interval.

There is a A SIC count >300: The threshold value used to identify potential lead failures. Here is what I got what I asked Meta AI:

The accuracy of the SIC (Sensed Impedance Change) counter in Medtronic pacemakers is generally high, but may vary depending on factors like:

1. Device model and software version

2. Lead design and positioning

3. Patient-specific factors (e.g., body size, tissue characteristics)

Medtronic's published data:

1. Sensitivity: 91-95% (correctly detecting lead impedance changes)

2. Specificity: 96-98% (correctly identifying non-changes)

3. Positive Predictive Value (PPV): 55-65% (true positives among alerts)

4. Negative Predictive Value (NPV): 95-98% (true negatives among non-alerts)

But I have a question around timeframe, it has rolling winback or accumulative window. Usually it is around 7-30 days.  But my father's data is set to 2 years.  

Who should I ask this question to? Does Medtronic have technical support for me to ask quesions? 

2 Comments

Here is the reply about timeframe for SIC > 300 from Meta AI

by smopace - 2024-09-28 02:43:34

Yes, the time frame for SIC (Sensed Impedance Change) counter >300 in pacemakers matters.

Time Frame Considerations:

1. Cumulative vs. Rolling Window:

- Cumulative: SIC count >300 since last reset.

- Rolling Window: SIC count >300 within a specified time frame (e.g., 1-30 days).

Common Time Frames:

1. Short-term (1-7 days): More sensitive for acute lead issues.

2. Medium-term (7-30 days): Balances sensitivity and specificity.

3. Long-term (30-90 days): Less sensitive, but useful for chronic lead monitoring. Medtronic's Recommendations:

1. Adapta/Sensia: 7-day rolling window.

2. EnRhythm/Consulta: 14-day rolling window.

3. Concerto: 30-day rolling window.

Study Findings:

1. Short-term (1-7 days): 95% sensitivity, 90% specificity (Journal of Cardiovascular Electrophysiology).

2. Medium-term (7-30 days): 92% sensitivity, 95% specificity (Medtronic's Concerto study).

List

by piglet22 - 2024-09-28 07:48:32

smopace, that's quite a list.

it gives you a feel for the complexity of modern pacemakers.

I wonder if there is a danger of information overload. As a fairly long term pacemaker user, I'm really only interested in a few things.

Does it keep me going? Is the heartrate OK? battery projected lifetime? how to fix ectopics problems.

One day, out of interest, I might ask for a copy of settings and my readings. It will make interesting reading, but that's about as far as it will go.

I do understand why you want to get as much information as possible. For some of my friends and relatives with devices, it's fit and forget. My poor aunt just couldn't get it out of her head that her device could be single use. I left it at that.

You know you're wired when...

Your pacemaker receives radio frequencies.

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Try to concentrate on how you’re able to be active again and feel normal, rather than on having a machine stuck in your body.