1-8
Introduction to MR Conditional Pacing
Conditions for Scanning
Table 1–4. Cardiology Conditions/Patient Conditions (continued)
Condition for Scanning
(Rationale)
Actions If Condition is Not Met
Potential Clinical
Consequences
Risk is Highest for
for patients with a pacing
threshold ≤ 2.0 V plus an
additional 1.0 V to counteract
gradient-induced pace pulse
offsets.
threshold testing results for
each chamber when MRI
Protection Mode is
programmed and provides an
attention message on the PRM
screen if > 2.0 V.
9. No abandoned leads or pulse
generators.
The presence of abandoned
leads or pulse generators may
significantly reduce the
effectiveness of the
ImageReady MR Conditional
Pacing System in reducing risks
of MRI scanning.
• Check patient records.
• Confirm with physician
responsible for managing
the patient's Pacing
System.
• Check X-rays.
• Arrhythmia induction
• Clinically significant pacing
threshold changes and
sensing changes as a
result of heating at the
lead/tissue interface
• Damage to pulse
generator, lead, or
connection
• Pocket discomfort due to
pulse generator heating
• Pacing-dependent patients
• Patients prone to sustained
arrhythmias
• Patients with high capture
thresholds
10. No evidence of a fractured
lead or compromised pulse
generator-lead system integrity.
Lead impedance values within
the programmed normal range.
No record or evidence of
damage to pulse generator seal
plug and front lead sealing
rings.
Abnormal lead impedance
values may indicate a short or
open circuit in the lead system.
This could result in abnormal
conductive trajectories and
induced voltages. Broken
conductors in the lead system
could result in increased
potential for heating at the lead
tip. A damaged seal plug or
front lead sealing ring could
promote an alternate current
flow path during MRI scanning.
• Check patient records for
most recent lead
impedance values.
• Review Daily
Measurements on the
Leads Status Summary
Screen to verify stability
over time of pace
impedance, pace
threshold, and intrinsic
amplitude values.
• Check patient records from
implant procedure.
• Check patient records for a
history of noise on EGMs.
The device measures lead
impedances upon user request
to enter MRI Protection Mode
and provides an attention
message on the PRM screen if
the values are out of the
programmed normal range.
A history of noise on EGMs
could be indicative of a
damaged seal plug or front lead
sealing rings.
• Arrhythmia induction
• Clinically significant pacing
threshold changes and
sensing changes as a
result of heating at the
lead/tissue interface
• Inappropriate pacing,
inhibition of pacing, or
irregular intermittent
capture or pacing, possibly
resulting in pre-syncope or
syncope
• Pacing-dependent patients
• Patients prone to sustained
arrhythmias
• Patients with high capture
thresholds
Table 1–5 Radiology Conditions on page 1-8 summarizes the Radiology-related Conditions of
Use that must be met in order for an MR Conditional MRI scan to be performed. For each
condition or requirement, actions to determine eligibility, the potential clinical consequences of
failing to meet the condition(s), and the patient population most impacted by failure to meet the
condition(s) are listed.
Table 1–5. Radiology Conditions
Condition for Scanning (Rationale) Actions If Condition is Not Met
Potential Clinical
Consequences
Risk is Highest for
1. MRI magnet strength of 1.5 T or 3 T (see a and b below).
1a.
MRI magnet strength of 1.5 T:
• Check technical
specifications of MRI
scanner.
• Arrhythmia induction • Pacing-dependent
patients
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