Discrimination of P and T Waves With Linq and Holter

Pilot Study of 20 prospective cardiology patients with loop recorders currently implanted for standard clinical indications. Eligible Subjects will be brought into the office of John Wilson, MD or Marshall Winner, MD. After informed consent is obtained from Hatton Research Staff the following will be performed: * subjects will have an initial loop recorder download to USB flash drive * 12 lead EKG * Annotated QT intervals on a 30 second rhythm strip * 24 hour Holter monitor placed by Hatton Research Staff in order to confirm the loop recorder data. * Subjects will be instructed on the Holter monitors care and use. * Subjects will be scheduled to come back to the office after 24 hours to return the Holter monitor and have a final loop recorder download completed. * Data from the loop recorder, Holter monitor, 12 lead EKG, and 30 second rhythm strip will be downloaded and de-identified per Hatton Research Staff. * All de-identified data from the initial loop recorder download, 12 lead EKG, 30 second rhythm strip, final loop recorder download, and Holter monitor will be sent to Medtronic for algorithm development. Independent Variables: These variables include age and race Dependent Variables: These variables include the data from the loop recorder, 12 lead EKG, Holter monitor and 30 second rhythm strip. Intervention or experimental aspect of the study Subjects will have a 12 lead EKG performed with 30 second rhythm strip Subjects will complete a period of 24 hours in which they will wear a Holter monitor applied by Hatton Research Staff. Statistical Analysis * Descriptive statistics (mean, standard deviation) will be calculated for all continuous variables. Continuous variables will be compared using Student's - T test or ANOVA as appropriate. * Frequency and percentages will be calculated for all categorical variables. * Categorical data will be compared using chi square or Fisher's Exact Test as appropriate * Data variables will be assessed by Hatton Research Specialist