Is Tachy-Brady (Tachycardia-Bradycardia) syndrome a contraindication for Coronary Computed Tomography Angiography (CCTA)?

Tachy-Brady Syndrome is a Contraindication for CCTA

Tachy-Brady syndrome (fast irregular heart rate) is a contraindication for Coronary Computed Tomography Angiography (CCTA) as explicitly stated in the 2024 ESC guidelines. 1

Rationale for Contraindication

The 2024 European Society of Cardiology (ESC) guidelines for chronic coronary syndromes clearly state that CCTA is not recommended in patients with:

• Fast irregular heart rate (which includes tachy-brady syndrome)
• Severe renal failure (eGFR <30 mL/min/1.73 m²)
• Decompensated heart failure
• Extensive coronary calcifications
• Severe obesity
• Inability to cooperate with breath-hold commands
• Any other conditions that can make obtaining good imaging quality unlikely 1

This recommendation carries a Class III, Level C designation, meaning there is consensus that CCTA should not be performed in these situations.

Technical Challenges with Tachy-Brady Syndrome

The technical reasons for this contraindication include:

1. Image Quality Issues: Tachy-brady syndrome causes unpredictable heart rate variations, making it extremely difficult to time image acquisition properly 2

2. Motion Artifacts: The irregular rhythm creates motion artifacts that significantly degrade image quality, potentially leading to non-diagnostic studies or false interpretations 2

3. Gating Difficulties: CCTA requires precise ECG gating, which becomes unreliable with unpredictable heart rate changes 3

Alternative Diagnostic Approaches

For patients with tachy-brady syndrome requiring coronary assessment, the guidelines recommend:

1. Functional Imaging Tests:

   • Stress echocardiography (Class I, Level B recommendation) 1
   • Stress SPECT/PET myocardial perfusion imaging (Class I, Level B) 1
   • CMR perfusion imaging (Class I, Level B) 1

2. Invasive Coronary Angiography (ICA):

   • Should be considered for confirmation of diagnosis when non-invasive tests are uncertain (Class IIa, Level B) 1
   • Recommended as first diagnostic test after clinical assessment in patients with symptoms highly suggestive of obstructive CAD that occur at low level of exercise 1

Heart Rate Control Considerations

Some centers attempt heart rate control before CCTA, but this approach has limitations in tachy-brady syndrome:

• β-blockers (commonly used for CCTA heart rate control) may worsen bradycardia episodes in tachy-brady syndrome 4
• Ivabradine has been used as an alternative to β-blockers for heart rate control during CCTA, but its efficacy in tachy-brady syndrome is not established 5

Clinical Decision Algorithm

When evaluating a patient with tachy-brady syndrome who needs coronary assessment:

1. First choice: Functional imaging (stress echocardiography, SPECT/PET, or CMR)
2. If functional imaging is non-diagnostic: Consider ICA with invasive functional assessment
3. If patient has high pre-test probability and severe symptoms: Proceed directly to ICA
4. Avoid CCTA due to high likelihood of non-diagnostic study and potential need for repeat testing

Conclusion

Tachy-brady syndrome represents a clear contraindication to CCTA based on current guidelines. The irregular heart rhythm makes it technically challenging to obtain diagnostic-quality images, and alternative imaging modalities should be selected based on local expertise and patient characteristics.