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Low-dose CT coronary angiography using prospective ECG-triggering: impact of mean heart rate and heart rate

Bernhard A Herzog1, Lars Husmann, Nina Burkhard

  • 1Cardiovascular Center, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland.

Academic Radiology
|December 10, 2008
PubMed

Insights

Low heart rate (HR) is crucial for high-quality low-dose computed tomographic coronary angiography (CTCA) with prospective electrocardiographic (ECG) triggering. While HR variability has minimal impact, maintaining a HR below 62 beats/min significantly improves diagnostic image quality.

Area of Science:

  • Cardiovascular Imaging
  • Radiology
  • Medical Technology

Background:

  • Low-dose computed tomographic coronary angiography (CTCA) utilizes prospective electrocardiographic (ECG) triggering for reduced radiation exposure.
  • Optimizing image quality in CTCA is essential for accurate diagnosis of coronary artery disease.
  • Heart rate (HR) and its variability are known factors influencing image acquisition in cardiac CT.

Purpose of the Study:

  • To assess the impact of mean heart rate (HR) and HR variability on image quality in low-dose CTCA with prospective ECG triggering.
  • To determine the optimal HR threshold for achieving diagnostic image quality.
  • To evaluate the role of HR control in enhancing CTCA efficacy.

Main Methods:

  • 129 patients underwent low-dose CTCA with prospective ECG triggering after HR optimization with beta-blockers.
  • Coronary segments were assessed for image quality on a 5-point scale by two independent readers.
  • Mean HR, HR variability, and radiation dose were recorded and analyzed in relation to image quality scores.

Main Results:

  • Mean HR during scanning was 58.4 ± 6.6 beats/min, with a mean effective radiation dose of 2.2 ± 0.7 mSv.
  • Mean HR, but not HR variability, significantly correlated with image quality (r = 0.49, P < .001).
  • A HR cutoff of 62 beats/min was identified, below which nondiagnostic segments were significantly less frequent (2% vs 14%, P < .001).

Conclusions:

  • Prospective ECG triggering enables low-dose CTCA, but requires strict HR control.
  • A low HR (< 62 beats/min) is critical for maximizing diagnostic image quality by prolonging the diastolic phase.
  • HR variability appears to have a negligible effect on image quality in this setting.
Abstract

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