In this Prestudy which will be followed by the multicentral GEx- main-trial, the feasibility of a new cardiac rehabilitation device (GEx system) is proved with coronary heart disease patients who participate in cardiac rehabilitation training exercise at the rehabilitation clinic (phase II) and subsequently at home (phase III). The GEx system consists of a easy-to-wear vest with integrated electrodes to measure electrocardiogram (ECG), respiration and activity, furthermore of a PDA to collect and store the monitored data and a cradle to charge the batteries. Several physiological parameters are extracted from thes measured vital signs like heart rate, breathing rate, ECG and activity. In this pretrial first the GEx sensor system is validated during guided exercise of the patients in the rehabilitation clinic (phase II). Subsequently at home (phase III) the practicability of the vest and sensors and possible technical problems in real- life use are proved. This means after moderate training like walking, cycling or running at home for 3 weeks patients will report the feasibility of usage. The ECG data and breathing- frequency data will be analyzed to see if data are recorded and transmitted well in regard to technical problems.

During the rehabilitation process (phase II) of patients with coronary heart disease (CAD) 30 patients are recruited and are made familiar with the new Guided Exercise (GEx) training system during exercise training; they are supervised and provided with training instructions by a medicine for 3 times a week 3 weeks long. At the beginning and at the end of the study the patient has to undergo several tests of the clinical routine such as a cardiopulmonary test (CPX), echocardiography and lactate measurement;additionally, this test will be registered by the system to obtain information about the detection of heart rate rise for example. Data will be analyzed for quality of heart rate measurement and data acquisition by the device.

In a second step the GEx system is handed to these 30 patients when they leave in-patient cardiac rehabilitation (CR). The pre-trial serves to gather information about the practicability and technical problem during real-life use. Therefore at home these 30 patients will continue with moderate endurance training like walking, cycling or running while wearing the GEx system three times a week for 3 weeks. After three weeks patients will come back to the clinic to undergo the end examination and to report the feasibility of usage. The ECG data and breathing frequency data will be analyzed to see if data are recorded and transmitted well in regard to technical problems.

If accurate and safe data are received the following GEx- main- trial (ID 11-020) will investigate the GEx- system for CAD patients in regard to improvement of physical capacities obtained in long term adherence to home based rehabilitation programs (phase III) including feedback to patients compared to national standard rehabilitation.

Inclusion Criteria:

• Patients suffering from CAD and presenting after an acute myocardial infarction or elective coronary intervention
• Patients willing to exercise
• With a preference for walking/ cycling/ running
• Eligible for the normal local rehabilitation program
• Contractually capable and mentally able to understand and follow the instructions of the study personnel
• Able to give informed consent

Exclusion Criteria:

• Ejection Fraction at discharge from hospital < 30%
• Unwillingness or lack of capability to handle the device
• Unable to perform exercise
• Severe congestive heart failure NYHA III/IV
• Severe valve disease without replacement
• Slow healing wounds
• Women who are pregnant or breastfeeding
• Refusal of device