Predictive Value of Ionized Calcium Level for Sinus Rhythm Conversion in Adenosine Treatment for Paroxysmal Supraventricular Tachycardia

Background: Paroxysmal supraventricular tachycardia (SVT) is a recurrent tachydysrhythmia that often leads to emergency department (ED) visits and is commonly treated with intravenous adenosine. Objective: The objective of this paper is to evaluate the relationship between the initial ionized calcium (iCa) level and the achievement of normal sinus rhythm following 6 mg adenosine administration in patients with SVT. Methods: This retrospective, single-center study was conducted in the ED from 2019 to 2023 and included consecutive adult patients diagnosed with SVT who received adenosine treatment. The patients were categorized into two groups based on their response to adenosine treatment. The receiver operating characteristic (ROC) curves were constructed to evaluate the effectiveness of iCa levels in predicting conversion to sinus rhythm. Results: A total of 326 patients were analyzed. The mean iCa level in patients who achieved a sinus rhythm after the initial 6-mg dose was 1.13 ± 0.08 mmol/L, as compared to 1.03 ± 0.11 mmol/L in those who did not respond to this dose, indicating a statistically significant difference (mean difference [95% confidence interval (CI)]: −0.101 [−0.12 to −0.07]). The area under the ROC curve was calculated to be 0.803 (95% CI: 0.752–0.854). An iCa cut-off value of 1.14 mmol/L was determined to be significant for the prediction of achieving sinus rhythm, with a sensitivity of 64.75% (95% CI: 55.6–73.2) and a specificity of 87.75% (95% CI: 83.6–92.7). Conclusion: Our study suggests that the iCa level may be a useful parameter for predicting the response to the 6 mg adenosine dose in patients with SVT.