Development and Validation of a Nomogram Model Affecting the ACT Targeting Rate During Radiofrequency Ablation of Atrial Fibrillation in China.

Context: A nomogram model affecting the activated clotting time (ACT) targeting rate during radiofrequency ablation of atrial fibrillation (RFCA) in China.

Purpose: The aim of this study is to develop and validate a nomogram model for predicting the activated clotting time targeting rate after the initial bolus heparin dosages during the radiofrequency catheter ablation of atrial fibrillation in China.

Methods and results: A retrospective observational study was conducted on the data of 465 patients with atrial fibrillation who underwent radiofrequency catheter ablation (RFCA) from October 2019 to June 2022. All patients were randomized into a training cohort (70%; n = 325) and a validation cohort (30%; n = 140). Independent risk factors were identified using univariate and multifactorial logistic regression analysis. The predictive nomogram model was established using R software. The nomogram was developed and evaluated based on differentiation, calibration, and clinical efficacy using concordance statistic (C-statistic), calibration plots, and decision curve analysis (DCA), respectively. The nomogram was established using three variables, including sex (OR 1.01, 95% CI 0.29-1.76, P = 0.007), heparin dose (OR 0.04; 95%CI 0.02-0.05, P < 0.001), and the baseline ACT (OR 0.03; 95%CI 0.02-0.04, P < 0.001). The C-statistic of the nomogram was 0.736 (95%CI 0.675-0.732) in the training cohort and 0.700 (95%CI 0.622-0.721) in the validation cohort. The calibration plots showed good agreement between the predictions and observations in the training and validation cohorts. The clinical decision curve also proves that the map is useful in clinical settings.

Conclusion: The nomogram model has good discrimination and accuracy, which can screen attainment groups intuitively and individually, and has a certain predictive value for the probability of ACT reaching the target after the adequate dosage of initial heparin in Chinese patients with atrial fibrillation.