Background: The 12-lead electrocardiogram (ECG) is an extremely useful tool for analyzing cardiac arrhythmias and numerous ECG algorithms have been developed to predict the origin of right ventricular outflow tract (RVOT) arrhythmias. Aim: To determine if using complex, time-consuming analysis, and difficult-to-memorize ECG algorithms is feasible and preferable before the ablation procedure when compared with the use of multipolar mapping catheter use during the ablation procedure. Methods: 47 consecutive patients admitted for radiofrequency catheter ablation of idiopathic PVC were included prospectively in this study. Of the algorithms selected for comparison, three have a memorable design and easy applicability (Dixit, Joshi, Pytkowski) and the fourth has a complex, detailed design and is more difficult to memorize (Zhang). Results: The greatest accuracy was observed for the algorithms proposed by Dixit and Pytkowski – 92. 3%. However, when the algorithms were compared for their accuracy, specificity, and sensitivity, no significant differences were found (p=0. 96). Conclusions: 3-D guided mapping using a conventional ablation catheter in a narrower, precise area of interest in the RVOT, based on ECG algorithms is not inferior compared to the multielectrode catheter mapping in the whole RVOT, in terms of mapping time, total procedural time, and radiofrequency application time.
Coronary CT angiography (CCTA) is used as a triage test before invasive coronary angiography (ICA). In this study we assessed the level of agreement between the two methods in patients whose CCTA reported severe stenosis in the presence of a low coronary artery calcium (CAC) score. We retrospectively analyzed 124 patients selected from a total of 2,742 examinations who underwent both CCTA and ICA. A discordant group (n=33) had stenosis reported on CCTA together with a low CAC (<400 and <100 AU). Across the whole cohort, obstructive disease (≥50% in the left main coronary artery or ≥70% in the other segments) was present in 44.4% of patients. In the discordant subgroup, agreement between CCTA and ICA was markedly worse: ICA showed obstructive disease in only 6.1% of patients. These results suggest that, although CAC remains a stand-alone predictor of obstructive disease, its predictive value is limited in a population already selected by referral for catheterization. The substantial discrepancy observed in cases where CCTA reports severe disease in the presence of a low CAC score raises the possibility that CCTA overestimates stenosis severity. In patients showing this pattern of discordance, non-invasive functional testing before referral to ICA could therefore be useful.
