Table 1.
Description of Study Parameters
| Metric | Description | Unit | |
|---|---|---|---|
| Electrogram morphology | EV | Peak-to-peak bipolar voltage at longest extrastimulus coupling interval | mV |
| ΔEV | Change in EV per unit change in extrastimulus coupling interval | mV/s | |
| ED | Time interval between first and last sharp electrogram components at longest extrastimulus coupling interval | ms | |
| ΔED | Maximal increase in ED at short extrastimulus coupling interval compared to baseline ED | ms | |
| Conduction | S1S2delay | The shortest S1S2 coupling interval conducting to the left atrium with S1S2 = A1A2 | ms |
| S1S2block | The shortest S1S2 coupling interval that conducts from pacing site to left atrium | ms | |
| ADT | Longest LA activation time (measured at shortest S1S2 coupling interval) minus shortest LA activation time (measured at longest S1S2 coupling interval) | ms | |
| Refractoriness | ERP | The longest S1S2 coupling interval at which S2 failed to produce local capture | ms |
ADT = activation dispersion time; ΔED = rate dependence of electrogram duration; ED = electrogram duration; ERP = effective refractory period; ΔEV = rate dependence of electrogram voltage; EV = electrogram voltage; LA = left atrial.