Reproducibility of the Adenosine‐5′‐Triphosphate Test in Vasovagal Syndrome

Vasovagal Syndrome: ATP Test Reproducibility. Introduction : Adenosine‐5′‐triphosphate (ATP) provokes negative chronotropic and dromotropic vagal effects. In vasovagal syndrome, ATP test (20‐mg IV bolus infusion) represents a promising technique for identifying patients at risk of severe cardioinhibitory response of vagal origin. The electrocardiographic and related symptom reproducibility of this descriptive test must be assessed. Methods and Results: In order to achieve this objective, ATP tests were performed twice in 80 patients (44 men, 36 women; mean age 72.3 ± 12.2 years) by using the recently published test procedure and criteria of positivity. The second test was repeated shortly after the initial test (mean: 7 days) in 43 patients and long‐term (mean: 3.7 years) in 37 patients. The initial ATP test provoked a cardiac pause > 10 seconds in 31 patients (39%) and a short cardiac pause (< 10 sec) or n pause in 49 patients (61%). The electrocardiographic outcome was reproduced during the second ATP test in 36 patients (84%) of the short‐term group and in 29 patients (78%) of the long‐term group. Similarly, symptoms were reproduced in 38 patients (88%) of the short‐term group and 29 patients (78%) of the long‐term group, reflecting the severity of the electrocardiographic outcome. Conclusion: The negative chronotropic and dromotropic vagal effect of ATP can he reproduced short term and long term in 84% and 78% of patients, respectively. Associated symptoms were related to the severity of the electrocardiographic outcome.