Introduction: Capturing cardiac electrical propagation or electrocardiographic images demands simultaneous, multidomain recordings of electrocardiographic signals with adequate spatial and temporal resolution. Available systems can be cost-prohibitive or lack the necessary technical specifications. We have designed and constructed a system that leverages affordable commercial products to create a complete, cardiac signal acquisition system that includes a flexible front end, analog signal conditioning, and defibrillation protection. The design specifications for this project were to (1) record up to 1024 channels simultaneously at a minimum of 1 kHz, (2) capture signals within the range of +/- 30mV with a resolution of 1 microV, and (3) provide a flexible interface for custom electrode inputs.
Methods: We developed and constructed such a system in collaboration with Itantech (CA, USA) using their existing 1024-channel neurological recording system, which had adequate sampling, but lacked the necessary range and signal conditioning for cardiac applications. We integrated their A/D conversion circuits to create a novel system that included signal attenuation, high-pass filtering suitable for cardiac applications, defibrillation protection, and a connector interface for our existing custom electrodes. The resulting system provides up to 1024 channels of +/- 33 mV input signal amplitude with cardiac signal conditioning and defibrillation protection. The system connects to a standard laptop computer under control of open-source software (Intantech).
Results: To evaluate the system, we recorded electrograms from within the myocardium, on the heart surface, and on the body surface simultaneously from a porcine experimental preparation. Noise levels were comparable to both our existing, custom acquisition system and a commercial competitor. The cost per channel was $32 USD, ($33,768 USD for a complete system).
Discussion: Our novel cardiac mapping system successfully recorded cardiac signals with a suitable sampling rate, bit resolution, and signal-to-noise at a cost substantially lower than contemporary systems.