Evaluating the imaging performance of ECG-less versus ECG-gated coronary CT angiography in patients with premature contractions.

OBJECTIVE: To compare the examination success rate, image quality, and diagnostic performance of coronary computed tomography angiography without versus with external electrocardiographic gating (ECG-less CCTA vs. ECG-gated CCTA) in patients with premature contractions (PCs). METHODS: This study included 416 patients with PCs who underwent both CCTA and invasive coronary angiography (ICA). The cohort consisted of 207 patients in the ECG-gated group and 209 in the ECG-less group. The groups were compared in terms of examination success rate, subjective image quality (5-point scale), and objective image quality metrics, including signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Diagnostic performance was evaluated against ICA (stenosis ≥ 50%) at patient, vessel, and segment levels. A chronological subgroup analysis was performed within the ECG-less group to assess potential temporal bias. RESULTS: Baseline characteristics were well balanced between the groups. The ECG-less group showed a significantly higher examination success rate (92.59% vs. 74.07%, p < 0.001) and superior subjective image quality (median score, 4.00 vs. 3.50; p < 0.001), whereas SNR and CNR were comparable between the groups. At the patient level, sensitivity, negative predictive value, and accuracy were significantly higher in the ECG-less group (93.71% vs. 84.97%, 71.05% vs. 42.22%, and 91.39% vs. 80.19%; p = 0.008, 0.009, and 0.001, respectively). Diagnostic performance at the vessel and segment-levels was also improved (all p < 0.017), except for vessel-level specificity (p = 0.061). The effective radiation dose was higher in the ECG-less group (5.33 mSv vs. 4.35 mSv, p < 0.001). Subgroup analysis revealed no significant temporal differences in the primary outcomes. CONCLUSION: In patients with PCs, ECG-less CCTA is a robust alternative that improves examination success and diagnostic accuracy by reducing arrhythmia-related artifacts without compromising overall image quality, providing a favorable benefit-risk profile despite a moderate increase in radiation dose.