Electronic Design

Wireless Technologies Work Together To Cheat Death

The Grim Reaper isn't a happy fellow these days as technology and medicine continue to keep people around. When you usually hear about someone coming back from the dead and getting a second chance at life, you assume it was dreamt up in Hollywood. Yet thanks to technology from Boston Scientific, people like my friend Tim can continue ticking for the foreseeable future.

Diagnosed with congestive heart failure (CHF) many years ago, Tim has had several heart attacks. In fact, he was declared clinically dead when he saw his cardiologist a little over a year ago because his heart wasn't sending the proper electrical signals to beat in a normal rhythm. This left Tim with two choices: imminent death or a chance for life with new technology.

Tim is one of the more than 1500 CHF patients who qualified for the Contak Renewal 3RF cardiac resynchronization therapy defibrillator (CRT-D). This device is implanted in the pectoral region of the chest with gold contacts placed in three of the heart's four chambers (Fig. 1).

The CRT-D primarily functions as a pacemaker. But it also can stop and restart a heart using a 41- Joule burst of energy when the pulse is too high or low. Additionally, it includes RF communication capabilities via the industrial scientific and medical (ISM) band in the 902- to 928-MHz range.

The CRT-D works with the Internetconnected Latitude Communicator (Fig. 2). The Latitude device sits under Tim's bed and continuously monitors and awaits data from the CRT-D at times specified by his physician during the CRT-D's original programming. (The CRT-D normally is programmed when it is implanted.)

A Bluetooth-enabled scale and a sphygmomanometer monitor Tim's weight and blood pressure daily. Subsequent to each reading, the data is transmitted to the Latitude device. When the system finds a pulse, weight, or blood pressure anomaly, it lets the patient know. In fact, Tim heard from the machine after a particularly stressful night.

"The next morning, out of the blue, a female voice says, 'You have questions to answer,'" Tim explained. The voice startled him until he realized it was the Latitude device, which continued to ask questions such as "How bad is your vision on a scale of one to four?" and "How many pillows did you use last night?"

Cardiologists working with Boston Scientific developed this set of quality- of-life inquiries based on the kinds of questions physicians would ask patients who are feeling uncomfortable and go to the doctor's office for a diagnostic visit.

"In the recent ACC/AHA guidelines for heart failure, close monitoring of a patient's weight and activities of daily living are a Class I recommendation. There is ample evidence that this type of approach can result in fewer hospitalizations for heart failure patients," said Greg Ewald, MD.

Each day, the Latitude device takes the information it collects and sends it via modem to a secure server accessible through the Latitude Web site. The combined technologies not only keep Tim and similar patients alive longer, they also keep physicians informed. Doctors can use the data to more quickly react to anomalies that may indicate an impending crisis - and prevent a visit from Mr. Reaper.

Boston Scientific www.bostonscientific.com

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