ECG Necklace Monitors Cardiac Performance in Daily Life

A prototype electrocardiogram (ECG) necklace enables long-term monitoring of cardiac performance and allows patients to continue their routine daily activities while under observation.

Developed by researchers at the Interuniversity Microelectronics Center (IMEC, Leuven, Belgium) and its research affiliate the Holst Center (Eindhoven, The Netherlands), the ECG necklace is easy to use and characterized by a low power consumption, which ensures a full week of autonomy. It contains a proprietary ultra-low power analog readout application-specific integrated circuit (ASIC), and relies on a low power commercial radio microprocessor platform. A wavelet-based heart beat detection algorithm is embedded in the processor that ensures accurate computation of the instantaneous heart rate, even under a high level of ambient noise. A second ultra-low power microcontroller unit controls the wireless transmission of the ECG data to a computer within a range of 10 meters; an optional memory module enables data logging for applications in which the receiving computer is not nearby.

The embedded beat detection algorithm has been optimized for robust heart beat detection, and copes with baseline wander, electromyogram (EMG) and motion artifacts, and high and variable electrode impedance. Heartbeat is detected with just one sample resolution. The algorithm achieves best-in-class performances, with 99.8% sensitivity and 99.77% positive predictivity, and satisfactory performance is achieved down to a level of 0dB SNR (signal to noise ratio). The innovative necklace was presented at the IEEE Engineering in Medicine & Biology Conference (EMBC), held during September 2009, in Minneapolis (MN, USA).

Related Links:
Interuniversity Microelectronics Center
Holst Center