Table 3.
Sensor-monitored force-frequency relation in normal and diseased hearts
| Clinical status | Force-Frequency Relation (FFR) | Diastolic time-frequency relation | S2-frequency relation |
| Normal | Upsloping FFR | systolic/diastolic time ratio < 1 | Normal upsloping |
| Normal recovery | Normal recovery | Recovery undershoot | |
| Acute ischemia | Acute biphasic FFR | Acute systolic/diastolic time ratio > 1 | Acute S2 blunting |
| Recovery overshoot | Recovery overshoot | Recovery overshoot | |
| CHF worsening ↓ | 1- Blunted FFR slope | ||
| ↓↓ | 2- From upsloping to biphasic FFR | Systolic/diastolic time ratio > 1 at lower HR | S2 blunting |
| ↓↓↓ | 3- Lower critical HR in biphasic FFR | ||
| - Recovery overshoot | Recovery overshoot | ||
| CHF improving ↑↑↑ | 3- Upsloping FFR | ||
| ↑↑ | 2- From biphasic to upsloping FFR | Systolic/diastolic time ratio > 1 at higher HR | Upsloping S2 |
| ↑ | 1- Higher critical HR in biphasic FFR | ||
| - Normal recovery | Upsloping S2 | ||
| Hypertension/diastolic failure | Blunted FFR | Systolic/diastolic time ratio > 1 at lower HR | Steeper S2 curve |
| Recovery overshoot | Recovery overshoot | Recovery overshoot | |
| Atrial fibrillation | Preceding and pre-preceding interval FFR dependence | Systolic/diastolic time ratio scattering | S2 scattering |
S2 = Second heart sound peak amplitude vibrations; HR = Heart Rate; FFR recovery overshoot = a relative increase in recovery FFR of more than 10% with respect to the exercise value