BoNT/A is a common treatment in patients with NDO. Possible known side effects are urinary retention or increased post void residual. Systemic side effects seems to be rare. However this has not been investigated in detail. Although in very small amounts, BoNT/A can enter the systemic circulation during intradetrusor injections and might cause distant effects on other neuro-muscular systems, i.e. the heart. Aim of this trial is to asses potential systemic adverse effects of BoNT/A on the heart following intradetrusor injections for NDO. Potential effects on the cardiac autonomic function can be detected using HRV analysis. Patients without relevant preexisting disorders of cardiac function and proven NDO are included. During four separate visits, all subjects receive two ECG measurements before (Visit 1 and 2) and two ECG measurements following BoNT/A intradetrusor injections (Visit 3 and 4). We investigate three different groups: 1) patients not receiving BoNT/A intradetrusor injections (= control group), 2) patients receiving intradetrusor injections with 100 units BoNT/A, and 3) patients receiving intradetrusor injections with 300 units BoNT/A.