CRT Algorithms Flashcards

Question

When does Adaptiv Bi-V Occur

Answer 1

A

The Adaptive Bi-V and LV setting can be summarized as a three step algorithm:

Step 1: The device assesses intrinsic conduction to determine if a patient’s AV interval is normal or prolonged.

Step 2: The device determines the pacing method to be either Adaptive LV or Adaptive Bi-V.

Step 3: The device optimizes the timing of the AV and V-V delays, and pacing configuration.

Answer 2

A

Intrathoracic impedance measurements are made at 20-minute intervals between 12:00 pm and 5:00 pm using the RV Coil to Can pathway (RV pace sense tip to Can in Consulta™ CRT-P), which passes through the tissue within the thoracic cavity. After all of the impedance measurements for a day have been made, the average impedance value is calculated for that day. The thoracic impedance graph, which is the lower graph, plots the average daily impedance value trend data. This daily impedance value is used to update a slowly adapting trend known as the reference impedance, which is calculated by the device. In this way, a control value for each individual patient is calculated. The device uses this control value to assess impedance variations.

If the daily impedance falls below the reference impedance, this may indicate that fluid is accumulating in the patient’s thoracic cavity. If the daily impedance remains below the reference impedance, the difference between the daily impedance and reference impedance values, adjusted for individual patient variation, is added to the OptiVol fluid index. While there is a difference between the daily impedance and the reference impedance, the fluid index may continue to increase. If the daily impedance begins to rise, this may be an indication that the thoracic fluid accumulation is resolving and the fluid index may decrease. When the daily impedance returns to the reference impedance, the fluid event is considered to have ended and the OptiVol fluid index resets to 0.