Effect of informed consent on anxiety in patients undergoing diagnostic electrophysiology studies

The process of informed consent has been suspected to raise patient anxiety, but this supposition has not been well studied or validated. The aim of this study was to evaluate the effect of a detailed informed consent protocol on patient anxiety. Fifty patients (36 men, 14 women, mean age 55 +/- 18 years) undergoing diagnostic cardiac electrophysiologic studies were enrolled. Patients were randomly assigned to receive either a consent that did not detail specific risks regarding the procedure (consent A) or one that detailed the risks (consent B). The Spielberger State-Trait Anxiety Inventory was administered before obtaining consent (state 1), immediately after the consent protocol (state 2), and after the electrophysiologic testing procedure, when the results of the test were known to the patient (state 3). Midazolam was administered during the procedure by staff who were blinded to the state/trait anxiety scores and the type of consent the patient had received. Patients receiving consent A had a significant decrease in state 2 anxiety compared with those who received consent B (adjusted mean difference 3.3; 95% confidence intervals 0.2 to 6.4). In the consent A group, 74% of patients received midazolam as opposed to 96% in the consent B group (p <0.02). Patients without inducible ventricular arrhythmias had a significant decrease in state 3 anxiety compared with those with inducible ventricular arrhythmias (adjusted mean difference 8.9; 95% confidence intervals 2.3 to 15.5). Thus detailed informed consent is associated with increased anxiety relative to a consent that does not detail specific risks. However, the difference in anxiety is mild and its clinical impact requires further exploration.