Download Isolated heart preparations have the advantage of being void of

Isolated heart preparations have the advantage of being void of confounding humoral and neuronal
input when studying the heart’s response to drugs or other interventions. Dynamic changes in left
ventricular pressure (LVP) and its derivatives, coronary flow and perfusion pressure, electrocardiogram
(ECG)-derived parameters, and other variables can be assessed over time. However, a reliable data
acquisition system (DAS) is critical to successfully conduct a meaningful experiment. Plug-and-play
DAS often have the disadvantage of limited flexibility because of proprietary software, limited
programmability and/or required specific signal conditioning systems. In contrast, LabVIEW allows
maximal user flexibility, but requires a significant amount of programming before use. We report the
design and operation of a LabVIEW-based Virtual Instrument (VI) for Langendorff-prepared isolated
heart experiments. All analog inputs from various signal conditioners are fed into an analog-digital
converter controlled by the VI’s DA assistant and sampled and displayed at 200 Hz. Thresholdcontrolled HR is calculated from ECG; systolic, diastolic and mean pressures are calculated from LVP;
for all less dynamic signals a running 3 sec average is calculated. Continuous or discontinuous data
recording can be initiated manually or by an internal or external trigger. Data read-out is continuously
appended into an Excel-compatible file. Thus, the described VI turns LabVIEW into an affordable
alternative to more rigid and expensive DAS while providing maximal flexibility for future adjustments