Re: Detrusor after-contraction on ambulatory urodynamics in symptomatic women I was very interested by the article of Veeratterapillay et al., 1 because it was published at the same time as an article written by my research team. 2 I agree with their finding that detrusor after-contraction (DAC) was probably associated with detrusor overactivity (DO). In our study, urodynamic diagnosis of DO was found in 54% of women without neurological disease or stage >2 prolapse; DO was phasic in 36%.However, there are some questions regarding the proposed conclusions.1 It is well known that ambulatory urodynamics results in a large occurrence of non-inhibited detrusor contractions during bladder filling (approximately twofold more than in conventional urodynamics, and it is also well known that in healthy volunteers approximately 10% of noninhibited detrusor contractions were found). 3,4 2 During ambulatory urodynamics, the bladder volume at onset of detrusor after contraction is not recorded. In our study, two criteria were imposed: post-void residual volume <30 mL, to avoid a possible resumption of the voiding process, and increase of detrusor pressure >10 cmH 2 O. I believe that the criterion of post-void residual volume is essential. DAC occurs in an almost empty bladder, and we cannot deny the concentration of stresses around the transducer. In their study, the authors found a lower voided volume; that result could be due to large post-void residual volume.3 The high prevalence of the association of DAC-DO in ambulatory urodynamics could be the consequence of artifacts due to the displacements of the probe during the movements of everyday life. To conclude, I believe that DAC is the result of local conditions perhaps favored by DO.
Franc ßoise A Valentini