Yes, CTA is Safe in Patients with Cardiac Monitoring Devices
CT angiography can be safely performed in patients with cardiac implantable electronic devices (CIEDs) including pacemakers, ICDs, loop recorders, and wearable monitors without requiring additional device interrogation or monitoring for modern devices 1, 2.
Safety Profile
The safety of CT imaging with cardiac devices is well-established:
Modern CIEDs are confirmed safe during chest CT scans, with electromagnetic interference occurring only in a few obsolete models (InSync 8040, InSync III Marquis, and Kappa), and even these resulted in no adverse events 2.
A large observational study of 2,362 chest CT scans across all device types (pacemakers, CRT devices, ICDs) demonstrated no deaths, bradycardia/tachycardia requiring scan termination, inappropriate shocks, or device malfunctions 2.
An extensive analysis of 516 CT scans with direct radiation exposure to CRMs showed zero instances of the composite safety endpoint (death, arrhythmias requiring intervention, device reprogramming, or replacement) 3.
Serial device interrogations revealed no differences in battery voltage or lead parameters between radiation-exposed devices and controls 3.
Image Quality Considerations
While CT is safe, the device itself may affect image quality through metal artifacts 1:
- Pacemaker and ICD leads cause beam hardening and streak artifacts, particularly around lead tips, which can impair assessment of coronary arteries 4.
- Artifacts are more frequent with unipolar leads and shock coils, primarily affecting the right coronary artery (RCA) 4.
- Left ventricular leads from CRT systems tend to affect the left circumflex artery (LCX) assessment 4.
- LVADs and some defibrillators create dense streaks that may partially obscure imaging 1.
Practical Recommendations
The presence of a cardiac device should not delay or result in cancellation of clinically indicated CT imaging 3. However, optimize the study as follows:
Protocol Adjustments
- Tailor the contrast protocol to the clinical question: use standard coronary CTA protocols for left-sided disease 1.
- For right-sided disease or lead endocarditis evaluation, perform a delayed venous phase acquisition to achieve more homogeneous right heart enhancement 1.
- Extend the z-axis range to include the entire chest when a pacemaker is present 1.
ECG Gating Challenges
- Unipolar pacing systems may cause problems with ECG gating due to difficulty differentiating R waves from pacing spikes 5.
- Bipolar leads working in bipolar mode are preferable for ECG-gated studies 5.
- Device reprogramming may be necessary in approximately 25% of cases to obtain diagnostic quality images 5.
- Manual ECG gating correction can salvage some studies when automatic gating fails 5.
Image Quality Enhancement
- Use dual-energy CT and postprocessing algorithms to reduce metal artifact impact 4.
- Maintain heart rate control when feasible, though beta blockers should be used cautiously in hemodynamically unstable patients 1.
Common Pitfalls to Avoid
- Do not withhold CT imaging based on outdated FDA advisory concerns from 2008, which were not supported by subsequent evidence 3.
- Do not routinely require device interrogation before or after CT in modern devices 2.
- Be aware that artifact occurrence cannot be reliably predicted before the scan, but diagnostic quality can be achieved in most cases with appropriate techniques 4.
The evidence consistently demonstrates that CT imaging, including CTA, poses no safety risk to patients with cardiac devices and should be performed when clinically indicated, with attention paid to optimizing image quality through appropriate protocols.