Medical diagnostic ultrasound instrument with ECG module, authorization mechanism and methods of use

A system for performing electrocardiography comprising:

• a portable ultrasound device having a transducer, a beamformer, an image processor and one or more digital signal processors for signal filtering, detection and mapping;
• a portable electrocardiogram monitor and having at least three electrical leads for measuring electrical potential across a person's chest, a differential amplifier for amplifying the measured electrical potential, a plurality of signal filters and gain amplifiers, and a means for electronically isolating the measured signal from other electrical inputs and interferences;
• and
• a portable display module for simultaneously displaying an image from said ultrasound device and signals from said electrocardiogram monitor;
• wherein signal processing circuitry of the electrocardiogram monitor includes first amplification and filtering circuitry for signals from the leads and second amplification and filtering circuitry for processing signals from the first amplification and filtering circuitry for application to the ultrasound device, the first and second amplification and filtering circuitry being electrically isolated whereby a patient is electrically isolated from the ultrasound device.