1. Trending Heart Rate and Replaying a Data FileThis example demonstrates how you can use the transformation features of BioBench to determine heart rate (beats per minute) and heart rate variability from a standard ECG signal. By determining the time interval between peaks (QRS complexes), BioBench can calculate and plot heart rate (and heart rate variability) as a function of time.
Note: This example does not require external hardware. You "acquire" data from a BioBench playback file.
BioBench can trend and display rate information (for example, heart rate, respiration rate, or any other periodic signal) during data acquisition. In this example, BioBench determines heart rate from an ECG signal. In addition, this example illustrates how the Data Source option allows you to "acquire" or replay an example data file or any other data file previously collected by BioBench.
- Select Configure»Data Source and click on the radio button labeled Demonstration/Teaching Data Sets.
- Highlight the file A Demo File.bb and click on the OK button.
- Select View»2 Graph Acquisition from the View menu to display both the ECG and the corresponding arterial pressure signal.
- Click on the Setup button in the trending area to enable trending and configure the beat per minute (BPM) calculation parameters as shown in the following figure.
- Click on the signal pull-down list in the trending area to display the names of all the signals on the screen. Select the ECG signal.
- Select the trend type from the pull-down list in the Trending area in the data acquisition view. You can select Min, Max, Mean, or BPM. For this example, select the BPM option.
- Click on the GO button to begin acquiring data from the example file. You will observe that the numeric indicator (above the Trend Setup button) displays the heart rate over the last ten seconds. Watch this value change over time and then proceed to the next step to view this data graphically.
- Click on the Trend button in the Trending area to see the trend graph like the one in the following figure. Try viewing the Trend Graph at different times as the trend values change over time. For more information about trending, refer to Chapter 3, Acquiring Data, of the BioBench User Manual (linked below).
- Eventually, replay of the data file will end, or you can choose to click on the STOP button.
2. Using Alarms to Display Heart Beats During Data Acquisition
To use an alarm indicator to display each beat (in other words, each QRS complex), perform the following steps:
- Select Configure»Settings, then select the Alarms tab in the Configure Settings for Acquisition dialog box that appears.
- Enable alarms by selecting the Alarms Enabled? checkbox, as shown in the following figure.
- Highlight the ECG signal as shown in the following figure. The ECG monitor in this example provides a -5 to 5 VDC analog signal. Because the QRS complex for this lead configuration yields a positive deflection, BioBench detects a heart beat when the waveform exceeds 1.25 VDC. Set the Alarm Type to Above Max. Enter a Max value of 1.25 in the Max text box. Give the alarm a label by typing heart beat into the Label text box.
- Click on OK to accept your settings.
- Click on GO to begin acquiring data from the example file. The alarm LED labeled heart beat should flash each time the heart beat alarm condition is met.
BioBench User Manual