Cardiac Compass Trends Feature

In Medtronic ICD and CRT devices, Cardiac Compass™ Trends provide up to 14 months of clinically significant patient data, including trends in the frequency of arrhythmias, physical activity, heart rates, and device therapies. Medtronic pacemakers provide an atrial arrhythmia trend and a histogram of ventricular rate during atrial tachycardia or atrial fibrillation (AT/AF). Medtronic Insertable Cardiac Monitors (ICM) include trends in the occurrence of arrhythmias and symptoms, the amount of physical activity and heart rate variability.

The Cardiac Compass Trends are based on data and measurements collected daily. Data storage for Cardiac Compass Trends is automatic. No setup is required. The device begins storing data after the device is implanted. Each day thereafter, the device stores a set of Cardiac Compass Trend data. Storage continues until the 14-month storage capacity is filled. At that point, the oldest stored data is overwritten with new data. An analysis of clinical information collected over a long term can help clinicians follow changes in a patient’s condition and correlate these changes with variations in device programming, medication, patient activity, or symptoms.

This feature can be found in some Medtronic Pacemaker, ICD, CRT-P, CRT-D, and insertable cardiac monitor (ICM) devices. Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.

Cardiac Compass Trend data is available without any programming. For legacy ICD and CRT devices, the report is only available in a printed format. To print, select Reports -> Available Reports… -> Cardiac Compass Trends -> Print. For the Viva™ family of devices, the Cardiac Compass is also viewable on the programmer screen during a programmer session.

Additionally, in CRT devices you can access the Heart Failure trends by going to Reports -> Heart Failure Management Reports.

For Adapta™, Versa™ and Sensia™ pacemakers, the trends will automatically print in the Initial Interrogation Report (Reports -> Available Reports -> Initial Interrogation Report). They can also be viewed on the programmer from the Quick Look™ II screen by clicking the Quick Link next to AT/AF. For Advisa MRI™, Revo MRI™, and Enrhythm™ devices, the report is available to print by selecting Reports -> Available Reports...-> Cardiac Compass Trends -> Print. For Advisa DR MRI and SR MRI, the Cardiac Compass is also viewable on the programmer screen during a programmer session.

For Insertable Cardiac Monitors (ICM), the trends can be selected to print automatically with the Initial Interrogation Report. You may also print the Cardiac Compass Report by going to Reports -> Cardiac Compass Trends…

The Cardiac Compass Report is also viewable on the CareLink Network, under Trends via a remote transmission. For ICD, CRT and pacemakers, there are 2 viewable options; 90 day zoom or 14 month view. For Reveal LINQ™ ICM, there are 3 viewable options on CareLink; 30 day, 90 day or 14 month view.

Depending on the type of device you are interrogating, you will be able to view and print different trends. The following table shows the available trends that can be printed from different device types.

ICM Pacemaker ICD CRT-P CRT-D

AT/AF Total hours/day

V. rate during AT/AF

Ave. V. rate

Patient activity

Heart rate variability

Atrial arrhythmia trend

V. rate during atrial arrhythmias

AT/AF total hours/day*

V. rate during AT/AF*

% pacing/day**

Avg day/night V. rate**

Patient activity hours/day**

Heart rate variability**

Programming/interrogation events

One or more shocks/day

Treated VT/VF

V. rate during VT/VF

Non-sustained VT

AT/AF total hours/day°

V. rate during AT/AF°

% pacing/day

Avg day/night V. rate

Patient activity hours/day

Heart rate variability

OptiVol

Atrial arrhythmia trend

V. rate during atrial arrhythmias

OptiVol

AT/AF total hours/day*

V. rate during AT/AF*

% pacing/day*

Avg day/night V. rate*

Patient activity hours/day*

Heart rate variability*

OptiVol

Programming/interrogation events

One or more shocks/day

Treated VT/VF

V. rate during VT/VF

Non-sustained VT

AT/AF total hours/day

V. rate during AT/AF

% pacing/day

Avg day/night V. rate

Patient activity hours/day

Heart rate variability

OptiVol

* This trend is only available in Advisa DR MRI, Revo MRI, EnRhythm, Viva CRT-P, Consulta CRT-P and Syncra CRT-P.
** This trend is available in Advisa DR MRI, Advisa SR MRI, Revo MRI, EnRhythm, Viva CRT-P, Consulta CRT-P, Syncra CRT-P. 
† This trend is only available in the Cardiac Compass Report. 
‡ OptiVol is not available in all device models.
 °This trend is available in Visia AF devices


Each trend provides unique clinical information. Together, the trends provide a clinical picture of the patient’s disease state. The table below lists each of the trends and how the data is collected.

Trend

Description

Programming and interrogation events

These events shows when the device was interrogated or programmed to allow possible correlations between device parameter changes and other clinical trends. When the patient is evaluated during an office visit, the report records an "I" for a day on which the device is interrogated and a "P" for a day on which any programmable parameter is changed (except for temporary changes). If the device is interrogated and programmed on the same day, only a "P" is displayed. When the patient is evaluated during a Medtronic CareLink® Monitor session, the report records an "I" with a line beneath it. Two vertical lines run through all the graphs to indicate the beginning of the current session and the beginning of the last session, if applicable. In addition, the ICM Cardiac Compass report may record an "S" when a patient marks a cardiac symptom by using a Patient Assistant during a symptomatic episode. If multiple events are recorded per day, one symbol is displayed per day according to system priorities.

One or more shocks per day

Any day on which the device delivered a high-voltage therapy is marked on this trend. Therapy includes an automatic defibrillation, cardioversion, or atrial shock therapy. Each annotation indicates delivery of one or more ventricular (V) or atrial (A) high-voltage therapies on a single day.

Treated VT/VF episodes per day

The history of ventricular tachyarrhythmias may be helpful in revealing correlations between clusters of episodes and other clinical trends. Each day, the device records the total number of spontaneous VT and VF episodes for which a therapy was started. This count may include therapies that were started and aborted. It does not include episodes that were only monitored.

Ventricular rate during VT/VF (bpm)

This trend may provide an indication of the effects of antiarrhythmic drugs on VT and VF rates and gives a better understanding of the safety margins for detection. The graph displays the median ventricular rate during spontaneous VT and VF episodes. Multiple points on one day represent multiple episodes with different median rates. The horizontal lines indicate the programmed VF, VT, and FVT detection rates, if applicable.

Non-sustained VT episodes per day

This trend may help you to correlate patient symptoms (such as palpitations) to non-sustained VT episodes and may indicate a need for further investigation of the status of the patient.

AT/AF total hours per day

This trend may help you to assess the need to adjust the patient’s device or drug-based therapies. This trend may also reveal the presence of asymptomatic episodes of AT/AF. The device records a daily total for the time the patient spent in atrial arrhythmia. The time in AT/AF is calculated from the point of AT/AF onset. This trend may be reported in hours (0 to 24) or minutes (0 to 60) per day depending on the maximum duration per day.

Ventricular rate during AT/AF (bpm)

You can use this trend to perform the following assessments:

  • Correlate patient symptoms to rapid ventricular responses to AT/AF.
  • Assess VT/VF detection safety margins and modify programming to avoid treating rapidly conducted AT/AF as VT/VF in the appropriate device.
  • Prescribe or titrate antiarrhythmic and rate control drugs.
  • Assess the efficacy of an AV node ablation procedure.

The graph plots average ventricular rates during episodes of atrial arrhythmia each day. The vertical lines show the difference between the average rate and the maximum sensed ventricular rate each day. The horizontal lines indicate the programmed VF, VT, and FVT detection rates, if applicable. Multiple points on one day represent multiple episodes with different median rates, if applicable.

Percent pacing per day

This trend provides a view of pacing over time that can help you to identify pacing changes and trends. The graph displays the percentage of all events occurring during each day that are atrial paces and ventricular paces. The percentages are calculated from the daily counts of AS-VS, AS-VP, AP-VS, and AP-VP event sequences. Atrial refractory events are excluded.

Percent CRT pacing per day

This trend displays the percentage of ventricular pacing per day and the percentage of effective CRT pacing per day. It is available in  Claria CRT-D devices. Review the EffectivCRT Diagnostic feature for more information.

Average ventricular rate (bpm)

The day and night heart rates provide information that may have the following clinical uses:

  • Objective data to correlate with patient symptoms
  • Indications of autonomic dysfunction or symptoms of heart failure
  • Information regarding diurnal variations

For this trend, “day” is defined as the 12-hour period between 8:00 am and 8:00 pm and “night” as the 4-hour period between midnight and 4:00 am (as indicated by the device clock).

Patient activity (hours/day)

The patient activity trend may provide the following information:

  • Information about a patient’s exercise regimen
  • An objective measurement of patient response to changes in therapy
  • An early indicator of progressive diseases like heart failure, which cause fatigue and a consequent reduction in activity

The patient activity trend is a 7-day average of data derived from the device rate response accelerometer. It is reported only after 14 days of data have been collected.

Heart rate variability (ms)

Reduced variability in the patient’s heart rate may help you to identify heart failure decompensation. The device measures each atrial interval or ventricular interval in the case of the ICM, and calculates the median atrial/ventricular interval every 5 min. It then calculates and plots a variability value (in ms) for each day.

OptiVol™ 2.0 fluid index

A decrease in thoracic impedance may be an early indicator of fluid accumulation associated with heart failure. The OptiVol 2.0 fluid index trend displays the accumulated difference between the measured daily thoracic impedance and the reference impedance, adjusted for individual patient variation. If the daily impedance is less than the reference impedance, this may indicate that the patient’s thoracic fluid has increased. The horizontal line shows the programmed value of the OptiVol threshold. The OptiVol fluid monitoring feature provides an additional source of information for patient management and does not replace assessments that are part of standard clinical practice.

Thoracic impedance

The thoracic impedance trend allows you to compare the daily average measured thoracic impedance to the reference impedance values. The reference impedance changes slightly from day to day to adapt slowly to the daily impedance.

 

The following is an example of patient with a recently implanted Claria MRI™ Quad CRT-D device.  Notice that % CRT Pacing/day is below 100% and % Effective CRT Pacing is approximately 75%. Review the EffectivCRT Diagnostic feature to learn more about effective CRT pacing. Other points of clinical interest are the short episodes of AT/AF/day with V. rates greater than 100 bpm.  In addition, there were to non-sustained VT episodes. The Cardiac Compass report provides a clear picture of the trends in order to assist in clinical diagnosis. After medical intervention, the report can be used to monitor arrhythmia, heart rate, pacing effectiveness in CRT patients, and fluid status.

ICM – Reveal LINQ Example

Below is an example of a Reveal LINQ, Cardiac Compass Report, 90 day view. The patient has had some atrial fibrillation which is noted in the AT/AF total hours/day trend. Other points of clinical interest are the relatively high heart rate that occurs while the patient is in AF (viewable via the V. rate during AT/AF trend). The patient's activity fluctuates with some dips below 1 hour/day mark. The patient's heart rate variability also fluctuates. The patient has several symptom indicated episodes as indicated by the multiple "S" annotations towards the later part of the 90 days. The Cardiac Compass report provides a clear picture of these trends and symptom annotations, in order to assist in clinical diagnosis. After medical intervention, the report can be used to monitor arrhythmia, heart rate and symptom correlation.

Since the Cardiac Compass report provides multiple pieces of clinical diagnostic data, this section will not review the extensive research available on the use of those individual diagnostics in device patients with varying device indications. However, one study in particular that looked at the combined utility of these diagnostics in the heart failure population is the PARTNERS HF trial.1 This study was a prospective, multicenter observational study in patients receiving CRT devices. A combined HF diagnostics algorithm was defined as positive if a patient had two of the criteria listed in Table 1 or if they only had a very high fluid index (≥ 100).

Table 1: Cardiac Compass Parameters and PARTNERS HF Criteria

Parameter Criterion
Fluid index ≥ 60
Fluid index ≥ 100
AT/AF duration ≥ 6 hours & not persistent AT/AF
V. rate during AT/AF AT/AF ≥ 24 hrs & V. ≥ 90 bpm
Patient activity Avg. < 1 hr over 1 week
Night heart rate ≥ 85 bpm for 7 consecutive days
HRV < 60 ms for 7 consecutive days
CRT % pacing < 90% for 5 of 7 days
Shock(s) 1 or more shocks


Clinical data from all patients with a positive combined diagnostic (assessed by reviewing the Cardiac Compass report) were analyzed using data from a 30-day window to predict the risk of HF hospitalization for the subsequent 30 days. Patients meeting any two of the listed criteria in the previous 30 days were considered to have a positive diagnostic. HF events were independently adjudicated.

The analysis concluded that patients with positive combined HF device diagnostics had a 5.5-fold increased risk of HF hospitalization with pulmonary signs or symptoms within the next month, and the risk remained high after adjusting for clinical variables. Based on this result, monthly reviews of HF device diagnostics can identify patients at a higher risk of HF hospitalizations within subsequent months.

Percentage of Monthly Evaluations 
With a Subsequent HF Hospitalization

References

  1. Whellan DJ, PARTNERS HF study. JACC. April 27, 2010;55(17):1803-1810.

Sources: Medtronic Adapta/Versa/Sensia Reference Guide; Medtronic Consulta CRT-P Clinician Manual;Medtronic Protecta XT DR Clinician Manual; Medtronic Claria MRI™/Claria MRI™ Quad CRT-Ds Reference ManualMedtronic Protecta XT CRT-D Clinician Manual; REVEAL LINQ™ Clinician Manual.

Last updated: 
21 Apr 2017