Recording the evoked canine detrusor electromyogram

With increasing interest in detrusor disorders and possible detrusor myopat hies, a method for recording the detrusor electromyogram (detrusor-EMG) wou ld probably greatly assist the diagnosis of various bladder dysfunctions. T herefore, we investigated the electromyographic activity of the detrusor du ring sacral root stimulation and during spontaneous bladder contractions in six anesthetized dogs. In all experiments, a high correlation of detrusor-EMG recordings with blad der contraction was observed. Analysis in the time domain and power spectru m analysis revealed the most clear correlation of detrusor-EMG with intrave sical pressure rise in a frequency band above 3 Hz. The spike duration was 100 to 250 ms with an amplitude of 100 to 500 mu V. Low-frequency activity below 1 Hz was mainly presumed to be artifacts due to fluid movement under the electrode. Our trials indicate that smooth muscle EMG recordings from the detrusor smo oth musculature are possible. The exact physiological relevance of the sign al in the sub-Hertz domain (<1 Hz) is still uncertain. The presented animal model allows the pathophysiologic investigation of various pathologies of bladder dysfunction and detrusor myopathies. (C) 1999 Wiley-Liss, Inc.