A smart-phone app under development for heart-failure patients allows them to keep track of the pressure inside their heart as measured by an implanted sensor. That data could help patients adjust their medication to maintain a healthy pressure, much as diabetics do with insulin and blood sugar readings.

Called Pam+ (for "patient advisory module"), the app is being developed by researchers at the University of Southern California in collaboration with medical device maker St. Jude Medical. The researchers hope it will help patients better manage their health and reduce hospitalizations, which are responsible for much of the $40 million in health-care costs linked to heart failure.

In congestive heart failure, pressure builds up in the circulatory system and the heart fails to pump blood adequately to the rest of the body. Fluid pressure changes by the day, and monitoring those fluctuations continuously is essential to treating heart failure effectively. A number of implanted devices are now under development to monitor this pressure, giving patients and doctors real time data.

The PAM+ app works in conjunction with an external device—developed by St. Jude and currently in clinical tests—that is placed over the heart, where it charges the implanted sensor and downloads data from it.

The data is forwarded to a server at St. Jude that analyzes it and returns, via the app, the latest readings and information about ongoing trends. A patient who has regularly monitored his or her heart pressure over a week will see a graph of pressure readings along with the message "Your heart thanks you." Users can easily share their data with their health-care team and family.

"We want patients to be able to access data but also to be rewarded and encouraged on a daily basis, so they don't feel like their whole life is a diet," says Leslie Saxon, a cardiologist and director of the Center for Body Computing at USC, who helped develop the device.

Previous research conducted by Saxon showed that remote monitoring can improve the health of heart-failure patients and lower health-care costs. She unveiled a prototype of the app at the Body Computing conference in Los Angeles today.

Users get points for monitoring their pressure—points that might eventually be tied to iTunes or Amazon credit. "Even a traditional payer would love to reward this type of behavior," says Saxon.

She believes an app like this can also change the nature of doctors' visits. Rather than a physician giving a patient the latest test results, taken at a few points in time, the patient can show the doctor measurements of heart pressure over weeks and months, and together they can discuss the trends these reveal.