Purpose <p>This study aims to evaluate the impact of different breath-holding techniques on the scanning length and radiation dose during coronary CT angiography (CCTA). </p> Materials and methods <p>A total of 210 patients with suspected coronary artery disease, who were scheduled for CCTA, were prospectively enrolled and randomly assigned to one of three breath-holding groups: Group A (end-inspiratory breath-hold), Group B (breath-holding during calm respiration), and Group C (end-expiratory breath-hold), with 70 patients in each group. The parameters recorded and analyzed included resting heart rate (during calm respiration), scanning heart rate (during breath-holding), scan length, heart rate variability, radiation dose metrics, and patient comfort levels. </p> Results <p>Four patients in the end-expiratory breath-hold group (Group C) were unable to maintain breath-hold during scanning, resulting in non-diagnostic images. The remaining 206 patients successfully completed the CCTA. Across all groups, the scanning heart rate was significantly lower than the resting heart rate (<i>P</i> &lt; 0.05). Follow-up assessments revealed that breath-holding during calm respiration provided the highest comfort level. Both the volume scan length and radiation dose were significantly lower in Groups B and C compared to Group A (<i>P</i> &lt; 0.05), with no significant differences observed between Groups B and C (<i>P</i> &gt; 0.05). The image quality in Group C was significantly lower compared to Group A and Group B (<i>P</i> &lt; 0.01).</p> Conclusion <p>Breath-holding during calm respiration in CCTA not only maintains the image quality, but also significantly lowers heart rate, scan length, and radiation dose, while simultaneously enhancing patient comfort and cooperation during the scan.</p>