50 study subjects scheduled for an EP procedure will have AleriTM sensors on subject's bicep, forearm, or wrist, to start data collection.

Measurements will be made from the subject for a period of approximately 1 hours prior to the EP procedure. . Measurements will continue as patient is moved to the operating room. Once the EP procedure is complete, the subject will be transferred from the operating room to a hospital room, where they will stay overnight. Measurements will be made for 3-5hours post-operation.Detailed analysis will investigate how does AleriTM data correlate with known measures such as saline volume/rate, urine production volume, USG, Blood osmolality and body weight;

AleriTM sensors are worn on the bicep or forearm and communicates through BLETM to a mobile App. The data is sent through the mobile App to web-based system processing where PHI is calculated and sent back to the mobile App.

The AleriTM sensor has a form factor similar to a conventional arm band, with a hockey puck shape of approximately 48mm in diameter and 15mm in thickness the AleriTM sensor is a non-significant risk (NSR) device as it does not meet the definition of significant risk device (21 CFR 812.3(m)) because it is: not an implant; is not purported or represented to support or sustain human life; its use is not of substantial importance in the diagnosis, cure, treatment, mitigation, or prevention of impairment of health; and it does not present a serious risk to the health, safety, or welfare of a subject.

Study team will compare the hydration status (changes in body water content) as predicted by the Aleri sensor to changes in volume according to the routinely reported volume exchanges. This will be a correlation study, and as such the purpose would be to use Pearsons' correlation between the device measurement and the interval changes in fluids ingested or excreted by the patient. There is no benchmark, but rather we will be looking for statistically significant correlation for any r>.5.