AF Detection Feature
- Patients at risk of developing AF
- Patients without a high percentage of ventricular pacing
- Patients experiencing palpitations and rapid heartbeats potentially associated with atrial arrhythmias
- Monitoring AF burden and the occurrence of asymptomatic episodes of AF, to assess whether medical treatment is necessary or should be adjusted.
This feature can be found in some Medtronic ICD devices. Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.
- AF Sensitivity
- Ectopy Rejection
- Record EGM for
To program this feature go to Params -> AF…
Review the feature operation for more information on programming each of the AF Detection parameters.
- If the device is programmed to be Less Sensitive it raises the threshold and requires more AF evidence (or RR interval variability) to detect AF.
- If the device is programmed to be More Sensitive it decreases the threshold and requires less AF evidence (or RR interval variability) to detect AF.
- AF detection occurs when the device detects atrial fibrillation for 6 minutes, this is nonprogrammable. AF episode storage is controlled by the “Record EGM for” parameter
- Ventricular pacing can regularize the rate and impact the ability to detect AF.
- If the patient has complete heart block and requires continuous ventricular pacing, AF will not be detected.
- If the R-wave interval variability is low, the 2-minute period is not classified as AF and the episode terminates.
- AF Detection is suspended, if any parameter(s) are programmed, or MRI SureScan is programmed to ON, during the 2-minute AF detection period.
- If there are 5 consecutive unclassified 2-minute periods. If any of the following events occur within a 2-minute period, the 2-minute period is considered unclassified:
- High level of ventricular pacing
- EGM Signal Noise
- Higher priority episode (e.g. VT/VF, SVT)
- T Wave Discrimination criteria is met
- RV Lead Noise Discrimination criteria is met
- Not enough R-wave intervals because events were excluded due to device operation, such as automatic battery measurements or capture threshold tests.
- Interval Plot
- EGM data
The EGM option displays two stored EGMs. The first is the high-gain LECG vector for P-wave visibility. The second is the standard EGM2 (Wavelet), far-field vector that provides a zoomed out view to see morphology. To optimize P-wave visibility, each stored atrial episode will have two stored EGMs: LECG and EGM2. If the LECG EGM and the EGM 2 (Wavelet) sources are the same, then you will see the same EGM on both channels in your EGM display.
The Text provides additional information about the episode such as total duration and median ventricular rate during the episode. Also, if the episodes terminated for any reason other than a low AF evidence score, the termination reason will be provided in the episode text.
- % of Time AF – The percentage of total time in AF.
- Average AF time/day – The average time in AF per day.
- Monitored AF Episodes – The average number of monitored AF episodes per day.
- AF Durations – The number of detected AF episodes for each of a series of time durations.
- AF Start
AF diagnostic information can also be found in the Cardiac Compass Trends. The AF Detection feature allows for the monitoring and recording of AF Burden and V-rate during AF trended information to support the clinical management of the patient.
- Boriani G,Glotzer TV, Santini M, et al. Device-detected atrial fibrillation and risk for stroke: an analysis of > 10,000 patients from the SOS AF project (Stroke preventiOn Strategies based on Atrial Fibrillation Information from implanted devices). Eur Heart J. 2014;35(8):508-516.