The Role of Device Diagnostic Algorithms in the Assessment and Management of Patients with Systolic Heart Failure: A Review
Table 1
Device diagnostics parameters and algorithms from the Cardiac Compass report.
Device diagnostic parameter
Description
Algorithm
AF duration
Total amount of time spent during AF on a daily basis.
AF ≥ 6 h on ≥1 day in patients without persistent AF (7 consecutive days with ≥23 h AF).
Ventricular rate during AF
The daily average ventricular rate during AF.
AF = 24 h and the average ventricular rate ≥90 beats/min during AF on ≥1 day.
Fluid index (OptiVol)
The fluid index trend is the cumulative difference between the daily average and patient-specific reference intrathoracic impedance.
High fluid index on ≥1 day; thresholds included ≥60; ≥80; ≥.
Patient activity
Measures the total active time per day using a capacitive accelerometer. A minute is considered active if the count exceeds a threshold equivalent to walking 70 steps/min.
Average patient activity <1 h over 1 week.
Night heart rate
Measures the ventricular rate from midnight to 4 AM.
Average night heart rate > 85 beats/min for 7 consecutive days.
Heart rate variability (HRV)
HRV is assessed by the SDAAM (standard deviation of the 5-minute median atrial rate). HRV is not measured if atrial pacing occurs >80% of the time or if the patient is in AT/AF.
HRV < 60 ms everyday for 1 week (minimum 5 consecutive days).
Percentage of CRT pacing
Percentage of biventricular pacing on each day.
Biventricular pacing <90% for 5 of 7 days.
ICD shocks for VT or VF
Records if an ICD shock was delivered for episodes detected within the VT or VF zone; includes both appropriate and inappropriate shock(s).
