Introduction The Autonomic Nervous System (ANS) is a complex network of nerves and ganglia which work to regulate a variety of sensory and motor systems without conscious effort (Berntson 2006). It is separated into two branches, the sympathetic and parasympathetic nervous systems. These two branches have very clear points of […]
Improving Data Quality: Cardiac Impedance
Before reading this article, check out these basic guidelines for ensuring good data collection which are universally applicable. Now we will get a bit more focused, and talk about signal specific data quality issues that can arise and how to deal with them. Disclaimer: Labeling data “good” or “bad” is […]
All About Cardiac Impedance Part 6: Deriving Respiration
Select analysis version to view the applicable content: For our final entry in the series on cardiac impedance, we are going to step back from analyzing the impedance signal directly and examine another way in which it can be used – to provide an index of respiration. Why this […]
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 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 […]