iPhone App Compared to Standard RR-measurement

Participants will be asked for consent at the University Hospital Basel at random based on availability. Recruitment is not limited to patients. After consenting patients will accompanied to a RR-measurement unit, positioned in a chair and kept at rest for 4 minutes. Then 7 blood pressure measurements at the same arm will be performed (Cuff/iPhone/Cuff/iPhone/Cuff/iPhone/Cuff). The Cuff measurement results will be documented in the source documents (mmHg) and transferred to a trial database. The iPhone data will be transferred with patient ID to "Preventicus" for calculation of the systolic blood pressure values (mmHg) based on the pulse waves recorded by transillumination of the index fingers of the participants. "Preventicus" will have NO access to the Cuff-measurement data. Then this data will be retransferred to the trial site and merged with help of the patient ID. Absolute and relative differences of the measured (Omron) and calculated (iPhone) systolic blood pressure values (mmHg) for will be calculated and published. A subgroup of 40 participants will be evaluated in a highly standardized fashion according the ESH (European Society Hypertension) guidelines for validation studies. These data will then be published separately for validation purposes.