Subjects in the experimental group (Physical Activity Promotion Telehealth Intervention) will receive messages on the study cell phone - approximately 2 to 3 messages every day. These messages will be tips to help them engage in physical activity and also to help them keep the physical activity appropriate. Walking will be primarily the suggested mode of activity.

Subjects in the attention control group will receive only general health messages on their study cell phone (not physical activity promoting messages). They also will receive any usual post-PCI procedure care that all get.

Subjects in the experimental group (Physical Activity Promotion Telehealth Intervention) will receive messages on the study cell phone - approximately 2 to 3 messages every day. Depending on the subject's responses to the questionnaires at baseline (stages and processes of change) they will be given tips to help them engage in physical activity (such as messages to increase their self-efficacy or confidence, walking with a friend or spouse, breaking up physical activity bouts into 10 minutes bouts, etc.) and also to help them keep the physical activity appropriate. Walking will be primarily the suggested mode of activity.

Evaluate the feasibility of each component of this pilot study, in order to refine the intervention for a larger clinical trial. This will include:

• Evaluate all aspects of implementation (numbers of subjects contacted, enrollment, attrition; problems and solutions identified using the telehealth platform, time for delivery; subject acceptance and perception).
• Evaluate feasibility of the data collection methods (time required for data collection, missing data, reliability estimates of outcomes).
• Estimate effect sizes for sample size determinations for a future, larger clinical trial.

Pilot test the impact of the Physical Activity Promotion Telehealth Intervention in post-PCI patients over time compared to patients receiving attention only, on the following outcomes:

• Movement through the stages of readiness for physical activity.
• Behavior change constructs (self efficacy for exercise, decisional balance, and use of processes for change).
• Amount of physical activity (estimated energy expenditure per day as measured by the actigraph accelerometer) and exercise (reported minutes exercising per day).