MRI-Ready Systems Manual

Introduction

This manual provides essential procedures and precautions for scanning patients implanted with a St. Jude Medical™™ MR Conditional system. It is crucial to read this information before conducting any MRI scan on such patients. For non-MRI related information, refer to the Merlin™™ Patient Care System (PCS) on-screen help or the appropriate device/lead user's manual.

A St. Jude Medical MR Conditional system comprises an MR Conditional device connected to one or more MR Conditional leads. Refer to the device/lead combination tables for specific tested combinations. The system remains MR Conditional when an unused port on the device header is fitted with a St. Jude Medical port plug.

Testing confirms that the St. Jude Medical MR Conditional system is conditionally safe for MRI environments when used as directed in this manual. Enabling MRI Settings activates a mode that allows safe scanning of patients with MR Conditional systems by MRI scanners, provided the instructions are followed.

CAUTION: MR Conditional product approval varies by country/region. Always consult St. Jude Medical or regulatory authorities to confirm MR Conditional certification before scanning.

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St. Jude Medical™™ MRI Safety Information

Personnel planning or performing an MRI scan on a patient with an MR Conditional system must adhere to the procedures and restrictions outlined in this manual. Failure to do so may result in serious harm to the device and patient.

NOTE: St. Jude Medical™™ MR Conditional systems can be scanned using 1.5 Tesla (1.5T) MRI scanners. Some systems are also compatible with 3.0 Tesla (3T) MRI scanners. Consult the following sections for specific MRI scanner types and scan parameters for MR Conditional device/lead combinations.

3T MRI Scan Parameters for St. Jude Medical™™ MR Conditional Systems

When performing a 3T MRI scan on a patient with a St. Jude Medical™™ MR Conditional system, the following scan parameters must be followed:

The above scan parameters apply to Full-body RF transmit coils with any receive coil.

CAUTION: For 3T MRI system RF excitation, ensure your scanner is operating as circularly polarized (CP) or quadrature (QD).

Multiple leads can connect to an MR Conditional device. Confirm each individual lead meets MRI conditions for use. Not all lead lengths are MR Conditional; refer to the device/lead combination tables for MR Conditional lead lengths.

3T MR Conditional Systems Device/Lead Combinations

Pacemakers

Pacemakers

1.5T MRI Scan Parameters for St. Jude Medical™™ MR Conditional Systems

When performing a 1.5T MRI scan on a patient with a St. Jude Medical™™ MR Conditional system, the following scan parameters must be followed:

The above scan parameters apply to the following RF coil types:

• Full-body RF transmit coil with any receive coil
• Local RF transmit-receive coil in Normal Operating Mode
• RF transmit-receive head coil (quadrature only)
• RF transmit-receive lower extremity coil (quadrature only)
• RF transmit-receive upper extremity coil (quadrature only)

WARNING: Do not place local RF transmit coils directly over the device, as this has not been tested.

CAUTION: Multiple leads can be connected to an MR Conditional device. Confirm that each individual lead meets MRI conditions for use. If the implantable system comprises leads with different scan parameters, use the most restrictive parameters for the entire system.

Not all lead lengths are MR Conditional. Device/lead combination tables list MR Conditional lead lengths.

1.5T MR Conditional Systems Device/Lead Combinations

Pacemakers

CRT-Ps

1.5T MR Conditional System Device/Lead Combinations for Quadra Allure™™ and Quadra Allure MP™ CRT-Ps

ICDs

1.5T MR Conditional System Device/Lead Combinations for Ellipse™™ ICDs

1.5T MR Conditional System Device/Lead Combinations for Fortify Assura™™ ICDs

CRT-Ds

1.5T MR Conditional System Device/Lead Combinations for Quadra Assura™™ and Quadra Assura MP™ CRT-Ds

Instructions for Cardiac Physicians and Clinicians

Cardiac physicians and clinicians are responsible for:

• Confirming the patient has an MR Conditional System.
• Confirming no adverse conditions to MRI scanning are present.
• Reviewing potential adverse events.
• Generating a report of the patient's permanently programmed parameters.
• Selecting and saving MRI settings.
• Reviewing the MRI checklist and programming MRI settings.
• Disabling MRI settings.

I. Confirm that the Patient has an MR Conditional System

1. Review the patient's ID card or Parameter report (from Merlin™™ PCS) for implanted lead/device model numbers.
2. Check these model numbers against the St. Jude Medical™™ MR Conditional Systems Device/Lead Combination tables (3T MRI tables page 3, or 1.5T MRI tables page 5).

NOTE: Not all lead lengths are MR Conditional. Check the device/lead combination tables for MR Conditional lead lengths. Untested lead lengths are not listed.

Patients are considered safe for MRI only if their implanted system consists of a St. Jude Medical MR Conditional device connected to appropriate MR Conditional leads.

II. Confirm that No Adverse Conditions to MRI Scanning are Present

Do not scan the patient if any condition makes MRI scanning unsafe. Such conditions include:

• Elevated body temperature or compromised thermoregulation, especially if the system includes specific leads (1944, 1948, 2088TC) or specific devices (Ellipse™™ ICD, Fortify Assura™™ ICD, Quadra Allure™™ CRT-P, Quadra Allure MP™™ CRT-P, Quadra Assura™™ CRT-D, or Quadra Assura MP™™ CRT-D).
• Device at End-of-Life.
• A combination of leads and a device not listed as MR Conditional in the device/lead combination tables.
• Broken or intermittently functioning St. Jude Medical™™ MR Conditional leads.
• Lead impedance measurements outside programmed limits.
• Additional hardware like lead extenders, adapters, or abandoned leads.
• System implanted in sites other than the left and right pectoral region. (See Figure 1: Correct locations for device implant, showing 1. Right-pectoral region, 2. Left-pectoral region).
• Patients with unstable capture thresholds.
• Patients with capture threshold values > 2.5 V (0.5 ms pulse width) for RA/RV leads or > 2.0 V (0.5 ms pulse width) for LV leads.
• Diaphragmatic stimulation at 5.0V or 7.5V (1.0 ms pulse width) when the device is programmed to asynchronous pacing mode during MRI Settings.
• For ICDs and CRT-Ds: Capacitor not prepared for the MRI scan (refer to Section VI).

NOTE: Lead fractures or damage can alter electrical properties, making the system unsafe for MRI. Patients with damaged leads may be harmed.

III. Review the Potential Adverse Events

St. Jude Medical™™ MR Conditional systems are designed to minimize adverse events. Potential events in the MRI environment include:

• Lead electrode heating and tissue damage, leading to loss of sensing or capture.
• Device heating causing tissue damage or patient discomfort.
• Induced currents on leads causing continuous capture, VT/VF, hemodynamic collapse, or all three.
• Damage to the device or leads, affecting detection or treatment of irregular heartbeats, or causing incorrect treatment.
• Damage to device functionality or mechanical integrity, preventing communication.
• Movement or vibration of the device or leads.
• Competitive pacing and potential VT/VF induction if asynchronous pacing is enabled with MRI Settings.
• Syncope due to loss of pacing if no pacing support is programmed with MRI Settings.
• For ICDs and CRT-Ds: Death due to untreated spontaneous arrhythmia if Tachy therapy is disabled during MRI Settings.

Potential interactions between the MRI scanner and the system include:

• Magnetic material in the implanted system can exert force, vibration, and torque due to static and gradient magnetic fields. These effects are minimal in St. Jude Medical™™ MR Conditional systems. Patients might feel a mild tugging or vibration at the implant site.
• Gradient magnetic and RF fields can potentially interact with the MR Conditional system, causing unintended heart stimulation. When all conditions are met, induced voltages and pulse widths on leads are limited to minimize heart capture potential.
• RF fields can induce voltages on implanted leads, causing electrode heating. This can damage surrounding tissue and compromise pacing/sensing thresholds. When all conditions are met, St. Jude Medical MR Conditional leads limit heating and minimize thermal damage.

IV. Generate a Report of the Patient's Permanently Programmed Parameters

CAUTION: Do not bring the Merlin™™ Patient Care System (PCS) Model 3650 or the SJM MRI Activator™™ handheld device Model EX4000 into Zone IV (MRI scanner magnet room), as defined by the American College of Radiology. Each device is MR Unsafe.

1. Interrogate the device with the Merlin™™ PCS.
2. If necessary, perform capture, sense, and lead impedance tests.
3. From the FastPath™™ Summary screen, select "Print" to generate the Diagnostics and other relevant reports. The Merlin PCS prints to the default printer (internal, external, or PDF).

NOTE: Device diagnostic data may be suspended or cleared when MRI Settings are enabled. Refer to the table for system behavior.

It is recommended that the clinician perform a complete follow-up prior to the MRI procedure to save all diagnostic data.

V. Select and Save MRI Settings

NOTE: The Merlin™™ PCS must be operating with software version 23.1.2 or greater to interrogate an MR Conditional device.

MRI parameter settings are determined at the physician's discretion. Default MRI parameter settings are automatically stored in the St. Jude Medical™™ MR Conditional device.

If MRI Settings are modified from default values, save them in the device. Refer to the Merlin™™ PCS on-screen help for selecting, testing, and saving MRI parameter settings.

1. After interrogating the device with the Merlin PCS, select the "Parameters" button to open the Parameters window, then select the "MRI Settings" tab.
2. Modify default MRI parameters as needed for MRI Settings.
3. For ICDs and CRT-Ds, select the appropriate HV lead type (Dual Coil or Single Coil).
4. Optionally, test settings using the "Test MRI Settings" button to evaluate patient hemodynamic status. Use "Cancel Test" to return to permanent settings.
5. Select "Save MRI Settings" to save any changes.
6. Note: MRI Pacing Chamber defaults to RV only in CRT devices. Left Ventricular pacing is turned off when MRI Settings are programmed.
7. If using the SJM MRI Activator™™ handheld device, review the MRI Activator Checklist and enable pulse generator communication. (See "Enabling the Device to Communicate with the SJM MRI Activator handheld device").
8. Ensure the device can communicate with the handheld device.
9. When satisfied, select "Setup for MRI Now" to run system integrity tests.

CAUTION:

• Regardless of the programmed pacing mode, sensed events are ignored when MRI Settings are enabled. If pacing support is needed, set MRI Mode to an asynchronous mode (DOO, AOO, or VOO). If not needed, set to Pacing Off.
• Some patients may be susceptible to cardiac arrhythmia from competitive pacing. Select an appropriate MRI pacing rate to avoid this and minimize asynchronous pacing duration.
• In MR Conditional ICDs and CRT-Ds, tachycardia therapy is disabled when MRI Settings are programmed.

Enabling the Device to Communicate with the SJM MRI Activator™™ handheld device

To use the SJM MRI Activator™™ handheld device, enable pulse generator communication via the MRI Settings window on the Merlin™™ PCS.

NOTE: If using the SJM MRI Activator handheld device, program V. AutoCapture 'On' prior to enabling MRI Settings to provide a safety margin against increased pacing capture thresholds due to lead tip heating post-MRI. Obtain in-range bipolar pacing lead impedance measurements from the current programming session before enabling communication.

To enable pulse generator communication:

1. Determine appropriate MRI Settings.
2. From the MRI Settings window, select the "Setup MRI Activator" button.
3. The MRI Activator Checklist window opens. Review and check off all applicable conditions. The "Enable MRI Activator" button becomes available only when all boxes are checked.
4. Select the "Enable MRI Activator" button.

The device can now communicate with the handheld device.

VI. Review the MRI Checklist and Program MRI Settings

After selecting MRI Settings, from the MRI Settings window on the Merlin™™ PCS, select the "Setup for MRI Now" button.

After system test measurements, the MRI Checklist window opens. Review and check all applicable conditions. MRI Settings cannot be programmed until all checkboxes are checked.

The MRI software verifies that no device or lead issues compromise patient safety during an MRI scan. It ensures:

• Pacing lead impedance is within range.
• Defibrillation lead impedance is within range.
• Capacitor maintenance is postponed for ICDs and CRT-Ds.

If system integrity tests are incomplete, "Perform Test" will be displayed. Click to run the test before enabling MRI Settings.

Once the checklist is complete, select the "Program MRI Settings" button to enable MRI Settings.

The "MRI Settings: Active" window confirms programmed changes. Use this window to print the MRI Summary report and end the session. MRI Settings can also be disabled here.

NOTE: If the programmer's Shock button is selected while MRI Settings are enabled, MRI Settings will be disabled, and the emergency shock dialog box will appear. Restore MRI Settings after an emergency shock before scanning.

Select "Print MRI Report" to print the report.

Select "End Session". The patient is now ready for the MR scan.

CAUTION: An ICD or CRT-D patient must be hemodynamically monitored while MRI Settings are programmed. An external defibrillator must be kept ready. Disable MRI Settings immediately after the MRI scan is complete.

VII. Disable MRI Settings

CAUTION: Do not bring the Merlin™™ Patient Care System (PCS) Model 3650 or the SJM MRI Activator™™ handheld device Model EX4000 into Zone IV (MRI scanner magnet room), as defined by the American College of Radiology. Each device is MR Unsafe.

Immediately following the MRI procedure, the patient's device management physician or clinician must:

1. Interrogate the device using the Merlin™™ PCS or the SJM MRI Activator handheld device.
2. If using the SJM MRI Activator handheld device, press the "MRI Settings Off" button.
3. If using the Merlin PCS, select the "Disable MRI Settings" button to restore permanently programmed settings.
• Confirm permanently programmed settings are appropriate.
• Perform a lead impedance test (Tests > Battery & Leads > Update leads) for accurate measurement.
• Check pacing capture thresholds after the scan to ensure adequate programming.

Refer to the Merlin PCS on-screen help for information on selecting and programming parameter settings.

NOTE: If the device performs an automatic lead impedance measurement during the procedure, the results may be inaccurate due to the MRI scanner's magnetic field.

Instructions for Radiologists and MRI Technologists

Radiologists and MRI technologists should refer to the "Instructions for Cardiac Physicians and Clinicians" (page 7).

Their role includes:

• Confirming the patient has an MR Conditional System.
• Confirming no adverse conditions to MRI scanning are present.
• Reviewing potential interactions.
• Selecting correct scan parameters.
• Checking MRI settings status.
• Performing the scan and monitoring the patient.
• Disabling MRI settings.

I. Confirm that the Patient has an MR Conditional System

1. Review the patient's ID card or MRI Summary Report (from Merlin™™ PCS) for implanted lead/device model numbers.
2. Check these model numbers against the St. Jude Medical™™ MR Conditional Systems Device/Lead Combination tables (3T MRI tables page 3, or 1.5T MRI tables page 5).

NOTE: Not all lead lengths are MR Conditional. Check the device/lead combination tables for MR Conditional lead lengths. Untested lead lengths are not listed.

Patients are considered safe for MRI only if their implanted system consists of a St. Jude Medical MR Conditional device connected to appropriate MR Conditional leads.

II. Confirm that No Adverse Conditions to MRI Scanning are Present

Do not scan the patient if any condition makes MRI scanning unsafe. Such conditions include:

• Elevated body temperature or compromised thermoregulation, especially if the system includes specific leads (1944, 1948, 2088TC) or specific devices (Ellipse™™ ICD, Fortify Assura™™ ICD, Quadra Allure™™ CRT-P, Quadra Allure MP™™ CRT-P, Quadra Assura™™ CRT-D, or Quadra Assura MP™™ CRT-D).
• A combination of leads and a device not listed as MR Conditional in the device/lead combination tables.
• Broken or intermittently functioning St. Jude Medical™™ MR Conditional leads.
• Additional hardware like lead extenders, adapters, or abandoned leads.
• System implanted in sites other than the left and right pectoral region. (See Figure 6: Correct locations for device implant, showing 1. Right-pectoral region, 2. Left-pectoral region).
• Prone or lateral recumbent patient positions, or positions where the patient's arm is raised above their head are excluded and have not been tested.

NOTE: Lead fractures or damage can alter electrical properties, making the system unsafe for MRI. Patients with damaged leads may be harmed.

III. Review the Potential Interactions

Potential interactions between the MRI scanner and the system include:

• Magnetic material in the implanted system can exert force, vibration, and torque due to static and gradient magnetic fields. These effects are minimal in St. Jude Medical™™ MR Conditional systems. Patients might feel a mild tugging or vibration at the implant site.
• Gradient magnetic and RF fields can potentially interact with the MR Conditional system, causing unintended heart stimulation. When all conditions are met, induced voltages and pulse widths on leads are limited to minimize heart capture potential.
• RF fields can induce voltages on implanted leads, causing electrode heating. This can damage surrounding tissue and compromise pacing/sensing thresholds. When all conditions are met, St. Jude Medical MR Conditional leads limit heating and minimize thermal damage.

IV. Select the Correct Scan Parameters

1. Refer to the MRI scan parameters tables (3T MRI table page 2 or 1.5T MRI table page 4) for applicable scan parameter settings for approved MR Conditional device/lead combinations.
2. Refer to the St. Jude Medical™™ MR Conditional Systems Device/Lead Combinations sections (3T MRI tables page 3 or 1.5T MRI tables page 5) for RF Power (SAR) and scan region settings.
3. Identify the specific combination of device and lead(s) to select correct settings.
4. If the system uses leads with different scan parameters, use the most restrictive parameters for the entire system.

V. Check MRI Settings Status

CAUTION: Do not bring the Merlin™™ Patient Care System (PCS) Model 3650 or the SJM MRI Activator™™ handheld device Model EX4000 into Zone IV (MRI scanner magnet room), as defined by the American College of Radiology. Each device is MR Unsafe.

If you do not have an SJM MRI Activator™™ handheld device, see "Check MRI Setting Status without the SJM MRI Activator™™ Handheld Device" (page 16).

If you have an SJM MRI Activator™™ handheld device, see "Check MRI Settings Status with the SJM MRI Activator™™ Handheld Device" (page 16).

Check MRI Settings Status without the SJM MRI Activator™™ Handheld Device

1. Refer to the MRI Summary Report generated by the Merlin™™ PCS.
2. Confirm these settings with the device management physician or clinician.

The currently programmed settings should include:

Check MRI Settings Status with the SJM MRI Activator™™ Handheld Device

To check the status of MRI Settings:

1. Refer to the table to determine if the device can communicate with the handheld device.
2. Place the handheld device over the implanted device (directly over the implanted pulse generator).
3. Press the "MR Status" button.

MR Status: MRI Settings Enabled. Green LEDs illuminate continuously for 5 seconds. MRI Settings Disabled. Red LEDs illuminate continuously for 5 seconds.

VI. Perform the Scan and Monitor the Patient

Proper patient monitoring is essential during the MRI scan. This includes continuous monitoring of hemodynamic function. As the MR environment may interfere with monitoring systems, use multiple systems (e.g., electrocardiography, pulse oximetry, noninvasive blood pressure).

If the patient's hemodynamic function is compromised, discontinue the MRI scan and take corrective measures.

Verbal communication with the patient during the MRI scan is recommended.

Keep an external defibrillator available during the MRI scan.

CAUTION: In MR Conditional ICDs and CRT-Ds, tachycardia therapy is disabled when MRI Settings are programmed.

CAUTION: An ICD or CRT-D patient must be hemodynamically monitored while MRI Settings are programmed, and an external defibrillator must be kept constantly ready. Be sure to disable MRI Settings as soon as the MRI scan is complete.

St. Jude Medical™™ MR Conditional leads have demonstrated minimal image distortion around implanted leads when the device is out of the field of view. Significant image distortion can occur when the device is within the field of view. Consider image artifacts and distortion when selecting the field of view and imaging parameters, and when interpreting MRI images.

VII. Disable MRI Settings

If using the SJM MRI Activator™™ handheld device, place it over the implanted device.

Press the "MRI Settings Off" button.

Red LEDs illuminate continuously for 5 seconds.

If not using the handheld device, MRI Settings must be disabled by the patient's device management physician or clinician using the Merlin PCS programmer.

Technical Support

St. Jude Medical maintains 24-hour phone lines for technical questions and support:

• 1 818 362 6822
• 1 800 722 3774 (toll-free within North America)
• + 46 8 474 4147 (Sweden)
• + 61 2 9936 1200 (Australia)

Website: manuals.sjm.com

For additional assistance, contact your local St. Jude Medical representative.