Magnetocardiography on an isolated animal heart with a room-temperature optically pumped magnetometer

TL;DR

This study demonstrates a room-temperature optically pumped magnetometer capable of detecting detailed magnetocardiograms from an isolated animal heart, offering a non-invasive, high-resolution tool for biomedical research and diagnostics.

Contribution

The paper introduces a highly sensitive, miniature optically pumped magnetometer optimized for biological signals, capable of real-time cardiac magnetic field detection at room temperature.

Findings

Detected heartbeat signals with P-wave, QRS, and T-wave in real-time.

Measured cardiac intervals such as RR and QT, including drug-induced prolongation.

Operates at room temperature and can be placed close to biological tissues.

Abstract

Optically pumped magnetometers are becoming a promising alternative to cryogenically-cooled superconducting magnetometers for detecting and imaging biomagnetic fields. Magnetic field detection is a completely non-invasive method, which allows one to study the function of excitable human organs with a sensor placed outside the human body. For instance, magnetometers can be used to detect brain activity or to study the activity of the heart. We have developed a highly sensitive miniature optically pumped magnetometer based on cesium atomic vapor kept in a paraffin-coated glass container. The magnetometer is optimized for detection of biological signals and has high temporal and spatial resolution. It is operated at room- or human body temperature and can be placed in contact with or at a mm-distance from a biological object. With this magnetometer, we detected the heartbeat of an isolated guinea-pig heart, which is an animal widely used in biomedical studies. In our recordings of the magnetocardiogram, we can in real-time observe the P-wave, QRS-complex and T-wave associated with the cardiac cycle. We also demonstrate that our device is capable of measuring the cardiac electrographic intervals, such as the RR- and QT-interval, and detecting drug-induced prolongation of the QT-interval, which is important for medical diagnostics.