It is possible to determine second-by-second heart rate values using Interval mode in the Heart Rate Variability analysis application. Interval mode can be enabled by navigating to the HRV Calibration Settings tab and changing the Calculation Method to Interval Interval mode allows you to split a given segment into smaller “intervals”, for […]
All About Cardiac Impedance Part 5: Data Editing
Select analysis version to view the applicable content: Now that we have talked about meaningful statistics in impedance cardiography and how they are calculated, we need to take a step back and make sure the data are clean and free of artifact. There are two steps for editing in impedance cardiography – […]
All About Cardiac Impedance Part 4: Systolic Time Intervals & More
Welcome back to the series on Cardiac Impedance. This time, we will use the key points identified last time on the dZ/dt ensemble average to determine important systolic time intervals (PEP, LVET) which will lead directly into additional cardiac indices of interest (stroke volume, cardiac output, total peripheral resistance) calculated […]
All About Cardiac Impedance Part 3: dZ/dt Component Identification
Select analysis version to view the applicable content: Last time we talked about how an entire segment of data is distilled down to an average representation of the cardiac cycle using ensemble averaging. Using the ensemble average, three landmarks are identified on the dZ/dt waveform: B, Z, and X. All three […]
All About Cardiac Impedance Part 2: Ensemble Averaging
Last time we introduced the following depiction of the dZ/dt signal: What we are looking at here is a single cycle of dZ/dt. In the IMP Analysis application, we distill a series of cardiac cycles down to a single average cycle for a given time period. It is from this average waveform […]
All About Cardiac Impedance Part 1: Introduction to Cardiac Impedance
All About Cardiac Impedance Cardiac impedance is a measurement of the mechanical activation of the heart. By recording cardiac impedance in conjunction with the electrical activation of the heart, the electrocardiogram (ECG), we can gain insight into sympathetic nervous system influence through measures such as Pre-Ejection Period, Stroke Volume, and Cardiac […]
KB0067: Scaling Skin Temperature to Degrees
The typical skin temperature probe used with MindWare systems requires a modified Transducer BioNex module to use. As with all transducers, the data will initially be displayed in volts. To scale this data to degrees (Fahrenheit or Celsius) you need to apply a known scaling equation in either BioLab or the Basic […]
KB0066: Scaling Cardiac Impedance to Ohms
Cardiac impedance is typically measured in ohms. It’s derivative, dZ/dt, is measured in ohms per second. This article will discuss the various ways of scaling data from volts to these more appropriate units in BioLab and the IMP Analysis application. If you are acquiring data with a MindWare Mobile, this […]
KB0065: Selecting a dZ/dt Source in IMP Analysis Application
Only two signals are required for analysis in the Impedance Cardiography (IMP) analysis application – ECG and Zo. The third signal used in analysis, dZ/dt, is the inverted first derivative of the Zo signal and can be derived in hardware and sampled during acqusition or derived in software post-acquisition. The hardware-derivation […]
KB0064: MindWare Mobile Events
While acquiring data using a MW Mobile, pressing the A and B buttons on the Mobile will insert a time stamped event marker in the data file for use during analysis. Local Mode In local mode, these events will always be labeled as “A” or “B” depending on the […]