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Total Anomaly Score (TAS) - User Guide

This article describes how to recognize and interpret the unique Cloud DX Cardiac Anomaly Scores. If you are a clinician interested in the scientific background and clinical applications of Cardiac Anomaly Scores, please request a white paper by emailing [email protected].

1. Overview

As part of its suite of results, Pulsewave reports on the Total Anomaly Score (TAS) of the pulse waveform. TAS indicates pulse characteristics found in the waveform and reports them in a statistical manner as a percentage of occurrences within the waveform. This information may be used by a professional as a screening aid in further diagnosing arrhythmia.

Arrhythmia is a cardiovascular condition in which the normal rhythm of the heartbeat is interrupted. Patients can be sent to take a costly ECG only to find that arrhythmia is not present. Pulsewave TAS helps by enabling a professional to make an informed decision on further testing.

2. TAS in Pulsewave results

During a Pulsewave reading it is very important to keep your arm still as this will provide the most accurate TAS analysis. TAS is reported with results in either the desktop client (Pulsewave PAS) or on pulsewavedx.com.  

 Image: Pulsewave PAS Dashboard showing TAS section from a most recent reading.

Dashboard

In the web client on www.pulsewavedx.com, you can see a general overview of your TAS results. Viewing the reading further will provide more information about the anomalies.

Image: Reading Summary view showing TAS for each reading.

Summary1

Clicking on one of the readings will allow you to view more information in the Reading Summary screen.  - there are colored vertical lines on the sphygmogram that indicate Anomalies - point these out with a box or arrow.

When the system detects an anomaly it displays colored vertical lines on the Pulse Waveform to report TAS.

Summary2

If you click on Details, you can further examine the results:

Details

Go even further still and examine the wave form with anomaly markers by clicking Pulse Waveform:

Pulse Waveform

3. TAS results in detail

TAS is broken down into classifications of anomalies. When reporting TAS, Pulsewave first gives an overall score, and then shows the components of that score. The definition and explanation of each result is as follows:

4. Total Anomaly Score (TAS)

TAS is the overall occurrences of pulse anomalies detected over the entire waveform. It is reported as a percentage and includes all of the sub-­scores below.

5. Duration Anomaly Score (DAS)

DAS is an aggregate score of all the pulse duration related anomaly scores. This is helpful to provide a high-­level indication of duration related anomalies. One can then observe specifically which duration related anomaly has taken place by observing:

a) Missing Pulse Score (MPS)

This is defined as the absence of a pulse where an otherwise regular pulse rate exists (i.e., if the missing pulse were inserted into the waveform, it would contain the underlying pulse rate). Many types of cardiac arrhythmias may present a missing pulse. Here is an example of a missing pulse indication:

Missing

b) Delayed Pulse Score (DPS)

This is defined as a pulse duration that is abnormally long. In contrast to a missing pulse, if a pulse were inserted during the delayed portion, it would not retain the underlying pulse rate. Many types of cardiac arrhythmias may present a delayed pulse.

Delayed

c) Premature Pulse Score (PPS)

This is defined as a pulse duration that is abnormally short, where the proceeding pulse may or may not have a compensatory delay. Many types of cardiac arrhythmias may present a premature pulse.

Premature

6. Amplitude Anomaly Score (AAS)

AAS is an aggregate score of all the pulse amplitude related anomaly scores. This is helpful to provide a high-­level indication of pulse amplitude related anomalies. One can then observe specifically which amplitude related anomaly has taken place by observing:

a) Low Amplitude Pulse Score (LPS)

This is defined as a pulse amplitude that is abnormally low (taking into account the oscillometric behavior of the pulse waveform). Low amplitude is typically observed together with a premature pulse. This decrease in relative amplitude of a pulse, especially when occurring during an arrhythmic event, is indicative of a change to the regular heartbeat.

b) High Amplitude Pulse Score (HPS)

This is defined as a pulse amplitude that is abnormally high (taking into account the oscillometric behavior of the pulse waveform). High amplitude is typically observed together with a delayed compensatory pulse occurring after a premature pulse. This increase in relative amplitude of a pulse, especially when occurring during an arrhythmic event, is indicative of a change to the regular heartbeat.

Here is an example of a pulse waveform that indicates DPS, PPS, LPS and HPS:

DPS, PPS, LPS and HPS

7. Other Cardiovascular Tools of Pulsewave

In addition to the TAS results, a professional can use the other cardiovascular results of Pulsewave to aid in the pre-­screening process of determining if further testing is required.

Pulse Rate (PRA)

Pulsewave will report the Pulse Rate Average as a result. This is the average rate of the pulses per minute as observed over the duration of the pulse waveform. Although Pulsewave does not specifically comment on the PRA, a professional can observe the result and draw conclusions based on the following:

Low Pulse Rate

This is defined as a regular pulse rate under 60 /min. If taken under normal conditions, this may suggest a form of bradycardia. Recall that the activation frequency of the SA node, which is the primary pacemaker, is normally 60 – 100/min.

High Pulse Rate

This is defined as a regular pulse rate over 100 /min. If taken under normal conditions, this may suggest one of the many forms of tachycardia.

Pulse Rate Variability (PRV)

Pulse Rate Variability is the percentage of change observed in the pulse rate as observed over the duration of the pulse waveform. It too does not report specifics about the result, but a professional can certainly use this value to draw conclusions based on the following:

Low Pulse Rate Variability

This is defined by highly constant pulse rates. If taken under normal conditions, this may suggest an AV block.

High Pulse Rate Variability

This is defined by highly variable pulse rates. Many types of cardiac arrhythmias may cause high pulse rate variability, for example, atrial fibrillation or a collateral effect of various other arrhythmias that result in premature, delayed, or missing pulses.

High Pulse Amplitude Variability

This is defined by highly variable pulse amplitudes (taking into account the oscillometric behavior of the pulse waveform). This may exist in the pulse following a missing, delayed, or premature pulse. It may also be a collateral effect of atrial fibrillation. This is because the amount of blood within the ventricles after atrial contraction is unpredictable, since the rate of atrial contraction itself is unpredictable. It may be a low volume of blood that may lead to an unusually low amplitude pulse, or a high volume of blood that may lead to an unusually high amplitude pulse.

Sudden Pulse Rate Change

This is defined as a sudden change between high and low pulse rates. If taken under normal conditions, this may suggest tachy-­brady syndrome. Sudden pulse rate changes should contain multiple delayed and/or premature pulses.