EffectivCRT Diagnostic Feature
Optimal CRT therapy requires a high percentage of effective biventricular (Bi-V) or LV-only pacing. However, device counters that indicate the percentage of Bi-V or LV-only pacing do not indicate whether the pacing was effective at successfully capturing the heart. Ineffective CRT pacing can be caused by several factors, such as the presence of AT/AF, AV intervals that are too long, inadequate LV pacing output, delayed LV activation, LV/RV electrode proximity, or atrial or right ventricular undersensing.
The EffectivCRT™ Diagnostic feature determines the percentage of effective CRT pacing by evaluating the morphology of the LV pacing cathode to RVcoil EGM. It provides data about the effectiveness of CRT pacing on the Quick Look™ II screen, Rate Histograms, Cardiac Compass™ Trends, and EffectivCRT™ Episodes. Visit the EffectivCRT™ During AF feature for more information.
- the EffectivCRT™ device check, which evaluates the ability of the device to detect effective CRT pacing under ideal conditions, was successful at least once since implant
- the device check is run 30 minutes after implant and then daily at 01:00
- the LV Amplitude is less than 8.00 V
- the V. Pacing is LV→RV or LV, or AdaptivCRT is enable
- the LV Amplitude was not increased and LV Pace Polarity or LV Pulse Width was not changed since the last successful EffectivCRT™ daily device check
- 8 consecutive ventricular events are sensed beats, safety paces, VSR paces, LV-only paces or bi-ventricular paces without effective CRT pacing
- at least 5 of those events are LV-only or biventricular paces without effective CRT pacing
- the date and time of the episode (note that data collection begins 25 min after the hour)
- the median atrial and ventricular beats per minute at the time of the episode
- an indication of whether an atrial tachyarrhythmia or atrial fibrillation (AT/AF) was present
- a 10 s strip chart of EGM
- event markers
- an indication of whether each ventricular pace, excluding Ventricular Safety Pacing (VSP) and Ventricular Sense Response (VSR) paces, was effective (Y) or ineffective (N)
- Hernandez-Madrid A, et al. Device Pacing Diagnostics Overestimate Effective Cardiac Resynchronization Therapy Pacing Results of the hOLter for Efficacy analysis of Cardiac Resynchronization Therapy Study (OLÉ Cardiac Resynchronization Therapy Study). Presented at CardioStim 2016 (Abstract 99-06).
Sources: Medtronic Claria MRI™/Claria MRI™ Quad CRT-Ds Reference Manual