INDICATIONS, SAFETY, AND WARNINGS Visia AF and Visia AF MRI

The Visia AF™ and Visia AF MRI™ SureScan™ ICD systems automatically detect and record the occurrence of atrial fibrillation (AF) for diagnostic purposes. The AF Detection feature analyzes variability in the ventricular rate to determine whether the patient is currently experiencing atrial fibrillation. Evidence of atrial fibrillation is based on ventricular rate variability assessed via a Lorenz plot.

The Visia AF MRI SureScan ICD Models are MR Conditional and, as such are designed to allow patients to be safely scanned by an MRI machine when used according to the specified MRI conditions for use. When programmed to On, the MRI SureScan feature allows the patient to be safely scanned while the device continues to provide appropriate pacing.


Indications for Use

The Visia AF and Visia AF MRI SureScan ICD systems are indicated to provide ventricular antitachycardia pacing and ventricular defibrillation for automated treatment of life-threatening ventricular arrhythmias.

A complete Visia AF MRI SureScan defibrillation system is required for use in the MR environment. A complete Visia AF MRI SureScan defibrillation system includes a Visia AF MRI VR SureScan ICD device with a SureScan defibrillation lead. When a single coil SureScan defibrillation lead is used, a Medtronic DF-1 pin plug must be secured in the SVC port to make a complete SureScan DF-1 defibrillation system. To verify that components are part of a SureScan system, visit mrisurescan.com. Any other combination may result in a hazard to the patient during an MRI scan.


Contraindications

The Visia AF and Visia AF MRI ICDs are contraindicated for patients experiencing tachyarrhythmias with transient or reversible causes including, but not limited to, the following: acute myocardial infarction, drug intoxication, drowning, electric shock, electrolyte imbalance, hypoxia, or sepsis; patients who have a unipolar pacemaker implanted, patients with incessant VT or VF, and patients whose primary disorder is atrial tachyarrhythmia.


Warnings and Precautions

Changes in patient’s disease and/or medications may alter the efficacy of the device’s programmed parameters. Patients should avoid sources of magnetic and electromagnetic radiation to avoid possible underdetection, inappropriate sensing and/or therapy delivery, tissue damage, induction of an arrhythmia, device electrical reset, or device damage. Do not place transthoracic defibrillation paddles directly over the device.

For Visia AF MRI System only:

Patients and their implanted systems must be screened to meet the following requirements for MRI: no implanted lead extenders, lead adaptors, or abandoned leads; no broken leads or leads with intermittent electrical contact as confirmed by lead impedance history; a SureScan defibrillation system implanted in the left or right pectoral region; pacing capture thresholds of ≤ 2.0 V at a pulse width of 0.4 ms; no diaphragmatic stimulation at a pacing output of 5.0 V and at a pulse width of 1.0 ms in patients whose device will be programmed to an asynchronous pacing mode when MRI SureScan is programmed to On.

Patients may be scanned using a horizontal field, cylindrical bore, clinical 1.5T or 3T MRI system for hydrogen proton imaging, maximum spatial gradient ≤ 20 T/m, and maximum gradient slew rate performance per axis ≤ 200 T/m/s.  1.5T scanners must be operated in Normal Operating Mode (whole body averaged specific absorption rate (SAR) ≤ 2.0 W/kg, head SAR ≤ 3.2 W/kg).  3T scanners must be operated in First Level Controlled Operating Mode or Normal Operating Mode.   B1+RMS must be ≤ 2.8 μT when the isocenter (center of the bore) is inferior to the C7 vertebra.  Scans can be performed without B1+RMS restriction when the isocenter is at or superior to the C7 vertebra.

Continuous patient monitoring is required while MRI SureScan is programmed to On. While MRI SureScan is programmed to On, arrhythmia detection and therapies are suspended, leaving the patient at risk of death from untreated spontaneous tachyarrhythmia. In addition, if the device is programmed to an asynchronous pacing mode, arrhythmia risk may be increased.


Potential Complications

Potential complications include, but are not limited to, rejection phenomena, erosion through the skin, muscle or nerve stimulation, oversensing, failure to detect and/or terminate tachyarrhythmia episodes, acceleration of ventricular tachycardia, and surgical complications such as hematoma, infection, inflammation, and thrombosis. Other potential complications related to the lead may include lead dislodgement, lead conductor fracture, insulation failure, threshold elevation, or exit block.

Potential MRI complications for the Visia AF MRI SureScan system include, but are not limited to, lead electrode heating and tissue damage resulting in loss of sensing or capture or both, or induced currents on leads resulting in continuous capture, VT/VF, and/or hemodynamic collapse; spontaneous tachyarrhythmia occurring during the scan that is not detected and treated because tachyarrhythmia detection is suspended while MRI SureScan is programmed to On; potential for VT/VF induction when the patient is programmed to an asynchronous pacing mode during MRI SureScan; device heating resulting in tissue damage in the implant pocket or patient discomfort or both; or damage to the functionality or mechanical integrity of the device resulting in the inability of the device to communicate with the programmer.

See the Device Manual for detailed information regarding the implant procedure, indications, contraindications, warnings, precautions, and potential complications/adverse events for all Visia AF devices and the MRI SureScan Technical Manual before performing an MRI Scan on patients with a Visia AF MRI system. For further information, please call Medtronic at 
1-800-328-2518 and/or consult the Medtronic website at
 medtronic.com or  mrisurescan.com.

Caution: Federal law (USA) restricts this device to sale by or on the order of a physician.