Methodology to establish non-invasive synchronous heart rate and heart rate variability measurement during uroflowmetry

Heart rate (HR) and heart rate variability (HRV) are established measures related to cardiovascular disease (CVD), a known risk factor correlated with lower urinary tract symptoms (LUTS) and overactive bladder (OAB). However, no standardized methodology exists to relate HR and HRV changes to uroflowmetry, the gold-standard evaluation for LUTS. Objective: to test the feasibility of methodology for synchronous, noninvasive measurement of HR and HRV, detrusor activity and uroflowmetry. Equipment: wireless continuous wave near-infrared spectroscopy (NIRS) instruments Poralite/Portamon (Artinis Medical Systems) with 3 wavelengths (785, 808, 830nm), spatially resolved configuration, and raw optical data collection at 25 to 100Hz. Protocol: Study subjects with and without LUTS provided data on voiding symptoms (validated International Consultation on Incontinence Questionnaire). Blood pressure and body mass index measurements allowed calculation of WHO cardiovascular disease risk. Subjects then wore the Portalite over the frontal cortex (HR and HRV monitoring) and the Portamon suprapubically (detrusor oxygenation monitoring). Device recording was linked synchronously to a wireless uroflow scale. Subjects were monitored for a 1-minute pre-void baseline, during voiding, and a 1-minute post-void baseline. Bladder scans confirmed bladder volume >150cc pre-baseline and measured post-void residual volume. N=40 (17 controls, 23 cases) completed the protocol. NIRS accurately monitored HR, HRV, detrusor oxygenation, and uroflowmetry in all cases. Synchronous, wireless monitoring to record the relationship between HR, HRV, detrusor activity, and uroflowmetry using non-invasive NIRS is feasible and generates reproducible results. This method will allow for larger scale studies analyzing the pathophysiology of CVD related to LUTS and OAB.