- Pauses of ≥ 3 seconds with Sx → ppm
- Pauses of ≥ 6 seconds without Sx → ppm
Bipolar tracing
- Atrial signal, RV, LV, Shock coil
- Why is the LV earlier than the RV?
- CRT - BiV pacing. Here, probably LV pacing alone.
- Only downside of LV pacing alone is that PR interval will change, e.g. with exercise. If you want to maintain stable, then need to know PR interval.
- Narrow is local electrogram
- At the bottom is what the device is seeing
- AS 900 - means 900 ms between atrial sense
- LVP - means LV pacing
- HRA typically has 4 electrodes on ‘em
- Right atrial appendage
- HBE - His bundle electrode
- CS - coronary sinus
Intracardiac recordings
- Surface leads are at the top (12 lead)
- HRA is typically next
- High right atrial catheter
- HBE
- A - H - V
- H-V interval: Measure His bundle activation to LV
- Notice how the surface lead QRS is before the V on HBE. We use the surface V (QRS) to measure H-V interval, and not the local V (which tends to be after the surface V)
- CS
- RVA
Bursts of Atrial Tachycardia
- Rapid atrial beats and then have pauses
- Turns on/off - triggered activity (membrane instability, ↑ adrenergic tone), not re-entry
- Conversion pauses - the SA node is reset
- Overdriving the intrinsic activity → slows way down (“I don’t need to go b/c someone else is going right now” And then when it takes a while for the automaticity to pick back up)