New Chip Detects Intracardiac Ventricular Fibrillation

The integrated circuit features three power-efficient, intracardiac electrocardiogram (ECG) signal readout channels; each of the three channels is equipped with a precision ECG signal readout circuit with very low-power consumption and an analog signal processor to extract the features of signal for detection of ventricular fibrillation.

The feature extractor achieves only 2 ms latency to facilitate responsive CRT. The chip also includes features that improve the functionality of CRT devices, such as a low-power accelerometer readout channel that enables rate adaptive pacing, and a 16-level digital sinusoidal current generator to handle intra-thoracic fluid analysis. The generator provides 82 db wide dynamic range bioimpedance measurement, in the range of 0.1–4.4 kΩ with 35 mΩ resolution, achieving over 97% accuracy. The chip was presented at the International Solid State Circuits Conference (ISSCC), held during February 2013 in San Francisco (CA, USA).

Robust and accurate heart rate monitoring of the right and left ventricles and right atrium is essential for CRT implantable devices. Accurate motion sensor and thoracic impedance measurements to analyze intra-thoracic fluid are critical for improving clinical research and analysis of the intracardiac rhythm. Moreover, extreme low-power consumption is required to further reduce the size of cardiac implants and improve the patient's quality of life.

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