ModifiedPremera BluecrossPolicy N/A

Mobile Cardiac Telemetry and Implantable Loop Recorders

Defines medical necessity criteria, documentation, site-of-service considerations, and coding for ILR implantation and MCOT use for ambulatory cardiac rhythm monitoring; intended for providers and applicable to Premera Blue Cross policyholders.

Policy Summary

PayerPremera Bluecross

PolicyMobile Cardiac Telemetry and Implantable Loop Recorders

Policy CodePolicy N/A

Change TypeMaterial revision — ILR addedMCOT criteria updatedcodes added

Effective DateMay 1, 2026

Next Review DateN/A

Key ActionObtain and document prior ≥14 days of non‑diagnostic external ambulatory monitoring before MCOT consideration; obtain prior authorization when required.

SourceLink

POLICY UPDATE CHANGES

Policy revised with an effective date of May 1, 2026 and last revised Apr. 14, 2026; changes also effective Aug. 7, 2026 referenced.

Title changed to Mobile Cardiac Telemetry and Implantable Loop Recorders and implantable loop recorders were added as medically necessary when criteria are met.

Added CPT code 33285 and HCPCS codes C1764, E0616; added Site of Service Ambulatory Service Center (ASC) guidance for implantable loop recorders.

14prior external monitoring (days)

48symptom frequency threshold (hrs)

33285, C1764, E0616codes added

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May 1, 2026effective date

1%MCOT emergent detections

Coverage and Medical Necessity Criteria

ILR and MCOT medical necessity criteria — distinct criteria for ILR (implantable) and MCOT (external) including patient-activated and auto-activated devices

Covered when ALL of the following are met:

ALL of the following

For implantable loop recorder (ILR) implantation (patient-activated or auto-activated): previous trial of other external ambulatory cardiac event monitoring was unsuccessful
Documentation must include results of prior external monitoring and reason for non-diagnostic or unsuccessful testing.
The individual has infrequent recurrent symptoms (e.g., palpitations, dizziness, presyncope, or syncope) such that symptom frequency is too low to be captured by short-term external monitoring
Clinical history must describe symptom frequency and correlation attempts.
Long-term monitoring is required for evaluation of atrial fibrillation (AF) or possible AF (for example, in evaluation of cryptogenic stroke) when indicated by clinical scenario and guideline recommendations
Document indication such as cryptogenic stroke or TIA and prior non-diagnostic shorter monitoring as applicable.

COVERAGE CRITERIA — Covered when ALL of the following are met (top-level ALL logic)

Covered when ALL of the following are met:

ALL of the following

An external ambulatory cardiac event monitoring trial of at least 14 continuous days was non-diagnostic>= 14 days
Record must show dates and type of external monitoring and non-diagnostic result.
AND one of the following clinical scenarios:
- The individual has symptoms of cardiac arrhythmia (recurrent presyncope, syncope, palpitations, or dizziness) occurring less frequently than once every 48 hours
  Symptom frequency should be documented in clinical notes.
- Evaluation of an individual with suspected atrial fibrillation as a cause of cryptogenic stroke or transient ischemic attack (TIA)
  Document prior stroke/TIA of undetermined cause and prior monitoring performed.

Coverage with criteria — clinical indications and device-selection guidance must be met and documentation of medical necessity required

Coverage with criteria — device-selection guidance and documentation requirements:

ALL of the following

Device choice should be guided by symptom frequency and clinical indication consistent with professional society recommendations (e.g., AHA/ACC/HRS). Shorter-term Holter or external monitors are preferred when events are anticipated within 48 hours; extended external monitoring (15–30 days) for events not daily; ILR reasonable for prolonged unexplained syncope or cryptogenic stroke evaluation
Reference professional society guidance in the medical record when applicable.
For MCOT (mobile cardiac outpatient telemetry): real-time monitoring is an enhancement but evidence is insufficient to show reduction in cardiac events; MCOT is considered medically necessary only when the policy clinical criteria are met (see prior 14-day external monitoring requirement and symptom or cryptogenic stroke indications)
Document why MCOT is selected over other external monitors and prior non-diagnostic monitoring.
For ILR: document prior external monitoring attempts, infrequent recurrent symptoms, or need for long-term AF detection; include office visit notes, relevant history and physical, and device implantation justification

Updated Medical Necessity Stance — policy updated to consider MCOT medically necessary under defined criteria and add ILR as medically necessary when criteria are met

Updated Medical Necessity Stance:

ALL of the following

MCOT is considered medically necessary when the specified criteria (including prior >=14-day non-diagnostic external monitoring and qualifying clinical scenarios) are met; MCOT is not medically necessary when these criteria are not met
This reflects policy update effective 04/08/2026 and 05/01/2026 editorial refinements.
Implantable loop recorders (ILR) are considered medically necessary when ILR-specific criteria are met (prior non-diagnostic external monitoring when applicable, infrequent recurrent symptoms, or need for prolonged AF detection such as after cryptogenic stroke)
ILR added as medically necessary when criteria are met per policy update effective 01/01/26 and finalized 05/01/26.

Coding and Procedure Codes

Covered CPT Codes (procedure)CPTCovered

33285

Insertion, subcutaneous cardiac rhythm monitor, including program.

Covered CPT Codes (monitoring)CPTCovered

93228

External mobile cardiovascular telemetry with electrocardiographic recording, concurrent computerized real-time data analysis and greater than 24 hours of accessible ECG data storage (retrievable with query) with ECG triggered and patient selected events transmitted to a remote attended surveillance center; review and interpretation with report.

Covered CPT Codes (monitoring)CPTCovered

93229

External mobile cardiovascular telemetry with electrocardiographic recording, concurrent computerized real time data analysis and greater than 24 hours of accessible ECG data storage (retrievable with query) with ECG triggered and patient selected events transmitted to a remote attended surveillance center for up to 30 days; technical support for connection and patient instructions for use, attended surveillance, analysis and transmission of daily and emergent data reports as prescribed by a physician or other qualified health care professional; review and interpretation with report.

HCPCS codes (implantable device)HCPCSCovered

C1764

Event recorder, cardiac (implantable).

HCPCS codes (device/equipment)HCPCSCovered

E0616

Implantable cardiac event recorder with memory, activator, and programmer.

FDA product codes mentionedmixed

DSH	FDA product code — ambulatory cardiac monitor category
DXH	FDA product code — ambulatory cardiac monitor category
DQK	FDA product code — ambulatory cardiac monitor category
DSI	FDA product code — ambulatory cardiac monitor category
MXD	FDA product code — ambulatory cardiac monitor category
MHX	FDA product code — ambulatory cardiac monitor category

Covered CPT Codes (added)CPTCovered

33285

CPT code for implantable loop recorder (as added to policy)

Covered HCPCS Codes (added)HCPCSCovered

C1764	HCPCS code added for device (as listed in policy)
E0616	HCPCS code added for device (as listed in policy)

inv-20: Symptom frequency threshold

Symptom frequency thresholdSymptoms occurring less frequently than once every 48 hours — symptoms < once every 48 hours indicate consideration of longer monitoring or ILR/MCOT per policy

Implication for monitoring selectionIf symptoms are less frequent than once every 48 hours, select extended ambulatory monitoring (patch/extended) or consider ILR when external monitoring is unsuccessful

Documentation requiredClinical notes must document symptom frequency (e.g., palpitations, presyncope, syncope, dizziness) to justify extended monitoring or ILR

inv-21: Prior external monitoring duration

Provider Responsibilities, Prior Authorization, and Documentation

Billing Rule

Billing and Coding

Codes associated with implantable loop recorder (ILR) and mobile cardiac outpatient telemetry (MCOT) services and billing guidance.

Covered CPT codes: 33285 (insertion, subcutaneous cardiac rhythm monitor, including programming); 93228, 93229 (external mobile cardiovascular telemetry services)
Covered HCPCS codes: C1764 (event recorder, cardiac — implantable), E0616 (implantable cardiac event recorder with memory, activator, and programmer)
Note: CPT/HCPCS code descriptions are copyrighted by AMA/CMS.

Prior Authorization

Prior Authorization, Coding Updates, and Site-of-Service

Prior authorization and site-of-service considerations apply for ILR and ambulatory cardiac monitoring per plan requirements.

Background and Evidence Summary

Implantable loop recorders (ILRs) and mobile cardiac outpatient telemetry (MCOT) are outpatient cardiac rhythm monitoring technologies used to detect intermittent arrhythmias that are not captured during brief in‑office testing. An ILR is a subcutaneously implanted memory loop device that provides long‑term, automatic rhythm surveillance over months to years and is useful for infrequent recurrent symptoms or extended AF monitoring. MCOT is an external continuous monitoring system that transmits rhythm data to a remote monitoring center for near real‑time analysis and is intended for continuous ambulatory surveillance when the policy criteria are met.

Definitions of Devices and Monitors

inv-40: ILR — definition of Implantable Loop Recorder (insertable cardiac monitor)

DefinitionImplantable Loop Recorder (ILR): an implanted memory loop device placed subcutaneously in the precordial region that provides long-term, automatic rhythm surveillance over months to years for intermittent arrhythmia detection

Typical clinical useUsed for recurrent, infrequent, unexplained syncope or prolonged monitoring to detect occult atrial fibrillation after stroke/TIA

Comparison to external devicesILRs provide longer monitoring and higher arrhythmia detection rates than short-term external monitors

inv-41: MCOT — definition of Mobile Cardiac Outpatient Telemetry (external continuous monitoring system)

DefinitionMobile Cardiac Outpatient Telemetry (MCOT): an external continuous monitoring system that transmits heart rhythm data to remote monitoring centers for near–real-time analysis

Policy Revision History

2026-05-01effective_dateLatest

Policy effective date updated to May 1, 2026 with revisions approved April 14, 2026; literature review updated through Dec. 2, 2025 and minor clarifications to ILR criteria and site-of-service language added.

2026-04-08material_change_effective

Major policy changes became effective April 8, 2026 following 90-day provider notification: title changed to Mobile Cardiac Telemetry and Implantable Loop Recorders; ILRs added as medically necessary when criteria are met; CPT and HCPCS codes added; SOS ASC guidance added.

Policy Summary

PayerPremera Bluecross

PolicyMobile Cardiac Telemetry and Implantable Loop Recorders

Policy CodePolicy N/A

Change TypeMaterial revision — ILR addedMCOT criteria updatedcodes added

Effective DateMay 1, 2026

Next Review DateN/A

Key ActionObtain and document prior ≥14 days of non‑diagnostic external ambulatory monitoring before MCOT consideration; obtain prior authorization when required.

SourceLink

On This Page

All documentation submitted for review must support medical necessity criteria.

Minimum prior external monitoring duration

At least 14 continuous days of prior external ambulatory cardiac event monitoring must be non-diagnostic before MCOT may be considered

Role in stepwise evaluationPrior ≥14-day external monitoring is expected before escalating to MCOT; ILR may be considered when external monitoring has been unsuccessful for infrequent symptoms

Documentation requiredMedical records must document prior external monitoring duration and that it was non-diagnostic to support MCOT request

inv-22: Monitoring duration guidance

Holter monitorTypical duration: 24–72 hours (used when symptoms anticipated within 48 hours)

Patch/leadless adhesive monitorTypical duration: ≥14 days (long-term recording option with improved patient acceptance)

Continuous monitoringTypical duration: 1–14 days (for quantifying arrhythmia burden and patterns)

Extended ambulatory ECGTypical duration: 15–30 days (used when symptomatic events are not daily or are uncertain)

Ambulatory cardiac monitors (including MCOT) and ILR are covered when medical necessity is documented; obtain prior authorization where required by the member’s plan.
CPT 33285 and HCPCS C1764, E0616 were added to the coding set effective with recent policy updates. Verify current code lists before claim submission.
For ILR, Ambulatory Service Center (ASC) site-of-service guidance was added; verify member benefits and site-of-service coverage.

Documentation Required

Medical Necessity Documentation Required

Document medical necessity thoroughly in the medical record to support coverage decisions.

Medical records must document the indication (e.g., symptomatic transient arrhythmias, unexplained syncope, suspected AF) and how the patient meets policy criteria.
Include office visit notes with relevant history and physical exam and documentation of symptom frequency, description, and timing.
For MCOT: document at least one of the policy-specified criteria (see MCOT criteria) and that a ≥14‑day prior external ambulatory cardiac monitor was non-diagnostic when required.
For ILR: document previous external ambulatory monitoring was unsuccessful and that symptoms are infrequent (examples: palpitations, presyncope, syncope) or there is a requirement for long-term monitoring for AF/possible AF.

Documentation Required

Document Arrhythmia Detection and Management

Document arrhythmia detection results and any subsequent management actions.

If AF is detected, document duration, correlation with symptoms, and resulting management (e.g., initiation of anticoagulation) as in published cohorts where AF detection led to treatment changes.
Record whether detected events were symptomatic or asymptomatic and any emergent interventions prompted by MCOT/telemetry findings.
Retain monitoring reports, transmissions, and physician interpretation in the chart to support clinical decision-making and claims.

Documentation Required

External Monitoring Before ILR

External ambulatory monitoring should generally be attempted before ILR when symptoms are more frequent; ILR is appropriate when prior external monitoring is unsuccessful or symptoms are infrequent.

For ILR: prior trial of external ambulatory cardiac monitoring should be documented as unsuccessful (non-diagnostic) before proceeding to implantable monitoring, unless clinical circumstances justify ILR without prior external monitoring.
MCOT may be considered medically necessary when prior external monitoring of ≥14 continuous days was non-diagnostic and other MCOT criteria are met.
Provide documentation of duration and results of prior external monitoring (type of monitor, dates, non-diagnostic findings).

Note

Monitor Selection by Symptom Frequency

Select the type of cardiac monitor based on symptom frequency and nature, consistent with guideline recommendations.

Use Holter monitoring when symptomatic events are anticipated within 48 hours.
Use extended ambulatory ECG (15–30 days) or patch monitoring when symptomatic events are not daily or are uncertain.
Consider MCOT for less-frequent events where real-time monitoring is clinically useful (MCOT is effective at detecting infrequent arrhythmias and may be preferred over standard event monitors when criteria are met).
Consider ILR for infrequent, unexplained syncope or recurrent infrequent symptoms when longer-term continuous monitoring is needed and prior external monitoring was non-diagnostic.

Continuously records or autotriggered memory loop data and transmits events to a central recording station with real-time monitoring

Typical useUsed when real-time/continuous monitoring and attended surveillance are desired for improved detection and rapid notification

inv-42: Holter monitor — definition and typical duration (24–72 hours)

DefinitionHolter monitor: a continuously worn device that records cardiac electrical activity throughout the recording period

Typical durationRecords continuously for 24 to 72 hours (commonly used when symptoms are expected within 48 hours)

ChannelsTraditionally 3-channel; some Holter monitors have up to 12 channels

inv-43: MCOT — expanded definition: continuously recording or autotriggered memory loop devices with remote transmission

Expanded definitionMCOT devices are continuously recording or autotriggered memory loop devices that transmit ECG data to a central recording station for real-time monitoring and analysis

CapabilitiesMay provide multilead monitoring, autodetection and autosend of events, immediate alarm generation, and attended surveillance

ExamplesDevice examples include CardioNet MCOT, LifeStar Mobile Cardiac Telemetry, Zio AT

inv-44: ILR — definition: implanted memory loop devices placed subcutaneously for prolonged monitoring

DefinitionILR: implanted memory loop devices (individual- or autotriggered) placed subcutaneously in the precordial region for prolonged monitoring

Monitoring durationProvides extended monitoring over months to years with automatic or patient-activated event capture

Clinical advantageAssociated with higher arrhythmia detection rates compared with short-term external monitoring

inv-45: Patch ECG monitor — leadless adhesive monitor for long-term recording (≥14 days)

DefinitionPatch ECG monitor: a leadless adhesive monitor that provides long-term recording (≥14 days) and improved patient acceptance

LimitationsTypically single-lead recording with potential variable signal quality and limited localization of arrhythmia origin

Use caseUseful when longer continuous recording is needed but implantation is not indicated

inv-46: Implantable cardiac monitor (insertable loop recorder) — subcutaneous device for extended monitoring for unexplained syncope etc.

DefinitionImplantable cardiac monitor (insertable loop recorder): a subcutaneous device for extended monitoring used for recurrent, infrequent, unexplained syncope or prolonged monitoring to detect occult atrial fibrillation

Evidence basisRCTs and observational studies report higher arrhythmia detection rates than short-term monitoring and support progression from external monitoring to ILR when longer monitoring is needed

Typical indicationsRecurrent infrequent syncope, cryptogenic stroke/TIA AF evaluation, and long-term post-ablation AF surveillance

inv-47: Mobile Cardiac Telemetry (MCOT) — historical note about investigational status and later policy acceptance

Historical statusMCOT was previously considered investigational in earlier policy iterations (e.g., 2016) but was reclassified in later updates

Policy transitionInterim and annual reviews document movement from investigational to medically necessary for defined criteria beginning in 2024 updates

ImplicationHistorical investigational status is noted but current policy permits MCOT when criteria are met

inv-48: Implantable Loop Recorder (ILR) — ILR added to policy as medically necessary when criteria met; references to CPT and HCPCS additions

Policy additionImplantable Loop Recorder (ILR) was added to the policy as medically necessary when specified criteria are met

Coding updatesCPT code 33285 and HCPCS codes C1764 and E0616 were added to the policy for ILR services and device billing

Site-of-service guidanceSite-of-service Ambulatory Service Center (ASC) guidance for ILR procedures was added to related policies section

Interim review approved January 9, 2024: MCOT criteria updated so MCOT is considered medically necessary rather than investigational.

2016-08-09policy_inception

New policy added to Cardiology section; at that time use of MCOT was considered investigational (policy effective date subsequently revised in 2017 iterations).

2016-08-09created

Policy created and added to Cardiology section; initial designation considered MCOT investigational.

2017-03-31effective_date_revision

Multiple effective date revisions in 2017 with final effective date adjustments through March 2017 as noted in the history log.

2016-08-01annual_review

Annual review entries recorded in subsequent years (2017–2023) with literature updates; policy statements remained largely unchanged through 2023.

2024-02-01interim_review

Interim review (approved January 9, 2024) added criteria making MCOT medically necessary rather than investigational.

2026-04-08major_revision_effective

Major changes effective April 8, 2026 after 90-day provider notification: title changed to Mobile Cardiac Telemetry and Implantable Loop Recorders; ILRs added as medically necessary when criteria met; CPT 33285 and HCPCS C1764, E0616 added; SOS ASC guidance added.

2026-05-01policy_effective_dateLatest

Policy header lists May 1, 2026 as the effective date for the revised document; last revised Apr. 14, 2026.

2026-04-08coding_additionLatest

CPT code 33285 and HCPCS codes C1764 and E0616 were added to the policy effective April 8, 2026 to describe ILR procedures and devices.

2026-05-01coding_confirmation

Policy revision effective May 1, 2026 (last revised Apr. 14, 2026) confirms addition of CPT 33285 and HCPCS C1764, E0616 and includes site-of-service guidance for ILR.