CARDIA's recording modules record instantaneous heart rate and/or systolic and diastolic blood pressures on a beat-to-beat basis for over 40.000 beats, together with up to seven channels of behavioral protocol. On-line display provides direct feedback to the experimenter. These modules, running under MS-DOS, perform reliably even on the lab's out-of-date XT- and AT-compatible computers. Recording module version 4 is designed for use with PhysioTel (Data Sciences International) implantable transmitters for blood pressure or combined ECG / body temperature measurement and requires an AT-compatible. It presents an oscilloscope-type display of the live signal, in addition to the time plot of heart rate, blood pressures or temperature, and behavior. It connects directly to the output of the receiver via its serial (COM) port and does not require additional hardware. Behavior can be protocollated via the keyboard. Presently, the built-in detection algorithms for systolic and diastolic pressure points and the ECG R-wave are specifically tuned to the rat. The previous version 3 employed a 10 kHz timer plug-in card, an A/D converter card in case an analog blood pressure transducer was used, and/or an external R-wave trigger circuit if an ECG was available, and an external protocollator unit (all hardware was built by our Electronics department). This version accommodated any animal species.

CARDIA's analysis module (version 3) offers flexible display options and calculates a number of cardiovascular statistics, per behavioral channel and pooled over all channels. Measures of heart rate variability include long-term variability (standard deviation of instantaneous heart rate and inter-beat intervals) as well as short-term variability (root-mean-square of successive differences). The analysis module includes an editing facility for data files. It can export data and analysis results in plain text or spreadsheet-readable formats. Hard copies of screen displays can be made on a Star-compatible matrix printer or an HP-compatible laser or ink jet printer, either during analysis or in batch mode.