Wissenschaftliche Basis des SRA – Analyseverfahrens

Stroke-Risik-Analysis - SRAclinic® Version 03 20.11.2017 – All previous version are no longer valid Seite 1

SRAclinic®

Report

Identification from patients with atrial fibrillation or an increased risk for paroxysmal atrial fibrillation

apoplex medical technologies GmbH Delaware Ave. 1-3 66953 Pirmasens Tel. 06331 - 6989980 Fax. 06331 - 69899819 www.apoplexmedical.com [email protected]

mailto:[email protected]


Contents

General information about SRAclinic®

The SRAclinic® Report

Results of SRAclinic®

Interpretation of Results

Management of SRAclinic® (web platform)

Appendix

SRAclinic® for the detection of AF after a stroke

The Lorenz Plot

Notes on Signal Quality


General information about SRAclinic®

In the clinical routine, it is important to obtain clearly arranged and understandable

information for the often difficult creation of the risk profile of a patient to be able to set the

best possible individual treatment concept as quickly as possible.

Especially in patients after a cryptogenic stroke, it is particularly important to initiate effective

therapy to detect potential paroxysmal atrial fibrillation (AF).

Our goal with SRAclinic® is to enable fully automated risk analysis in the simplest and most

reliable way with very little work (especially compared to manual long-term ECG analysis)

over a long period of time.

In the study Rizos et al. in Stroke1, it could be shown that this objective has been achieved

with impressive results. Thanks to automated ECG monitoring during the stay of the patients

in the stroke unit, approx. 40% more patients with paroxysmal AF were detected than in the

previous routine with 24 hours long-term ECG and checking patient monitors. In comparison

to the 24 hour long-term ECG evaluation, an increase of 170% could even be achieved.

On one hand, the success of SRAclinic® is based on the fact that the maximum available

recording time of patient ECGs is used and on the other hand because the underlying

algorithm automatically detects patients with existing fibrillation episodes with a similar

quality as if a cardiologist were to analyze all of these ECGs. This results in a very high

detection rate of patients with manifestation of fibrillation episodes with very little work. In

addition, the algorithm examines the ECG for possible deviations in the sinus rhythm, which

indicate fibrillation episodes that occurred in the past (PLOS One Study2) and is noted as a

risk for paroxysmal atrial fibrillation in the report.

SRAclinic® is a web-based system required for analyzing a two channel, digital long-term

ECG. This is sent to the central SRAclinic® server via the Internet, evaluated completely

automatically, and the result of this risk analysis is documented in a report as PDF.

Afterwards, it is the sender as an attachment via email.

Because SRAclinic® is used primarily in an environment of clinical intensive care medicine,

the use of the ECG data from the patient monitoring system is an obvious option. At present,

there are interfaces for connecting the SRAclinic® application to systems of the

manufacturers Dräger, Philips and Nihon Kohden. For users who do not have one of these

systems in use, the ECG recordings can be made with conventional long-term ECG

recorders.

1 Timolaos Rizos, Janina Güntner, Ekkehart Jenetzky, Lars Marquardt, Christine Reichardt, Rüdiger Becker, Roland Reinhardt, Thomas Hepp,

Paulus Kirchhof, Elena Aleynichenko, Peter Ringleb, Werner Hacke and Roland Veltkamp; Continuous Stroke Unit Electrocardiographic

Monitoring Versus 24-Hour Holter Electrocardiography for Detection of Paroxysmal Atrial Fibrillation After Stroke. 2 Schaefer JR, Leussler D, Rosin L, Pittrow D, Hepp T (2014) Improved Detection of Paroxysmal Atrial Fibrillation Utilizing a Software-Assisted

Electrocardiogram Approach. PLoS ONE 9(2): e89328. doi:10.1371/journal.pone.0089328


The SRAclinic® Report in connection with:

Dräger and Nihon Kohden patient monitoring systems

In connection with the patient monitoring systems from Dräger and Nihon Kohden, the

SRAclinic® Reports are transmitted completely automatically once per day. In this case, you

receive the complete analysis of the previous day for all patients, for whom an identification

number has been entered on the monitoring system.

Philips patient monitoring system

In connection with a Philips patient monitoring system, the ECG data of the selected patient

are transmitted once every day. The time of the data transmission can be freely selected, but

it has been shown in practice that a transmission in the morning makes sense. You receive

SRAclinic® of the selected patient up to the previous 24 hours.

Long-term ECG recorder

SRAclinic® analyzes up to a maximum of 72 hours of ECG recordings in the case of the use

of long-term ECG recorders. After submission of the ECG, a SRAclinic® for the recorded

period is created and then transmitted immediately.


An exemplary SRAclinic® Report is shown in the next figure:

2

3

4

5

1

6

7


The SRAclinic® Report is composed of the following areas:

1. Address – can be changed via the personal area of the SRA® platform.

2. Date information – the date of report creation and exam date are displayed.

3. Patient data

The name of the patient can be entered in the Patient name field. *

The entered identification number is shown in the Patient number field.

4. Analysis results – The result of the analysis is displayed here.

5. Hour sections – Number of evaluable hour sections.

6. Lorenz plot – A reference to manifestation of atrial fibrillation on the Lorenz plot is

depicted here.

7. ECG- Start Viewer – All details of the original ECG recording can be accessed

simply and quickly with the SRAviewer®. Especially conspicuous segments from the

Lorenz plot can be attributed to the corresponding ECG data with a mouse click.

* For data protection reasons, no direct personal data are transmitted.


Results of SRAclinic®

The following results determined by SRAclinic®:

No risk for paroxysmal atrial fibrillation

Increase risk for paroxysmal atrial fibrillation

Signs of manifest atrial fibrillation

Not analysable

Interpretation of the risk levels

No risk for paroxysmal atrial fibrillation

No episode of manifest atrial fibrillation and no increased risk for paroxysmal atrial fibrillation was detect.

Increase risk for paroxysmal atrial fibrillation

An increased risk for paroxysmal atrial fibrillation was detected, altrough no fibrillation episodes occumed during the entire recording. In the evaluable ECG section no fibrillation episodes were detected. Due to the high sensitivity of the analysis, it is to be assumed that there is very probably no flickering episode. This result, how detects an increased risk for atrial fibrillation in absence from manifest atrial fibrillations, provides the diagnostician before the biggest challenge. The study results and existing literature show that a further search for paroxysmal AF will be much more successful than without preselection in this risk group. How much effort should be operated for advance (more SRA® investigations further long-term ECG, implantable loop recorder...), it also largely depends on many additional diagnostic parameters such as atrial size, mitral regurgitation, etc. from.

Signs of manifest atrial fibrillation

An arrhythmia which has typical characteristics of manifest atrial fibrillation , was detected. A particularly representative ECG section is shown and used for validation. Despite a high specificity , a false positive result can not be excluded. The pictured ECG section has to be checked by a doctor.

Not analysable

It could be performed no analysis due to a bad signal quality , a low voltage or

morphological changes of the QRS complex.


Notes:

SRAclinic® is based on the analysis of the rhythm (RR intervals). Further evaluations

such as pathological QRS complex, ST segment elevation, prolonged PR interval,

etc. are not carried out.

SRAclinic® results can be influenced by cardiac pacemakers, strong ventricular

extrasystoles and pharmacological cardioversions. No SRAclinic® analysis should be

conducted in these cases.

5 min. ECG segment:

If manifestation of one or more atrial fibrillation episodes is detected, the sides 2 (channel 1)

and 3 (channel 2) contain the ECG segment, which display it in a particularly illustrative and

representative way. No ECG segment is present during the recording, which displays this in

a more illustrative and representative way.

To ensure that the reliability of detecting atrial fibrillation episodes is at a high level, great

emphasis was placed on a very high sensitivity (even with short episodes) at the request of

many users. As a result, false positive results can also occur, but they are rare and can be

evaluated relatively easily by the supplied 5 min. ECG segment. Many users, cardiologists in

particular, confirmed this procedure to be beneficial.

If the 5 min. ECG segment is incorrectly positive, no atrial fibrillation episodes are in the rest

of the ECG either.

The 5 min. ECG segment is provided with sufficient resolution and can be enlarged up to

400% with a PDF reader without loss.

Example for a 5-minute ECG-Stripe with atrial fibrillation


Management of SRAclinic® (web platform)

The SRA® platform is available for access to the SRAclinic® Reports, which can be

accessed with user name and password via the homepage www.apoplexmedical.com. All

reports are stored in chronological order here and can be retrieved up to three months after

the evaluation. Starting the SRAviewers® to evaluate the ECG recordings is also possible

from here. The management of personal data (address, email, etc.) is also possible on the

platform as well as the installation of the transmission software if a conventional long-term

ECG recorder is used.

It is possible to access the data with a password from any computer workstation (with

Internet access).

Display of the individual hourly

Lorenz plots

Lorenz plots of the individual

hours in the order from left to right and from top to bottom.

The hour and the signal quality

are given under each plot.

Empty coordinate systems are a sign for non-evaluable ECG data, e.g., due to poor signal quality. Hour sections without contents (no coordinate system) at the end of the overview mean that the ECG recording was stopped.

http://www.apoplexmedical.com/


Appendix


SRAclinic® for the detection of AF after a stroke


The Lorenz Plot

The Lorenz plot provides an excellent method for the visualization of the dynamics of the

heartbeat, often also called the Poincaré Plot. The times between two QRS complexes (RR

interval) are displayed in such a way that an interval is drawn against the next one in a

coordinate system. This can be done in two dimensions (x,y) as shown in the next figure.

Example:

RRn 0

RRn 0

RRn+1

Please note:

The analysis is based on many different

mathematical parameters. Properties of

the Lorenz plots are only a part of these

parameters. Consequently, the result of

the analysis cannot be derived solely from

the Lorenz plot.

The Lorenz plot also provides you with

the possibility of obtaining visual

information about the variability of the

heart rate.


The signal quality has decisive influence on the analysis of the data. Please be sure to

follow the instructions for performing good ECG recording.

The display of the signal quality in the SRAclinic® Report allows you to check the recording

quality. The following signal qualities are displayed:

1 - Excellent

2 - Good

3 - Satisfactory

4 - Sufficient – please repeat recording if necessary.

6 - Not evaluable

Note: SRAclinic® is carried out fully automatically and in particular can occasionally lead to

a faulty detection of QRS complexes (R waves) and the detection of ventricular extrasystoles

(VES), which can affect the risk assessment in connection with bad signal quality .

It may happen that SRAclinic® cannot always reliably distinguish between errors and VES or

does not detect all RR intervals. Errors are often manifested in randomly distributed points in

the Lorenz plot (Fig. 1). Missing R waves are indicated by other clubs with double distance in

x and y directions (Fig. 2).

The detection of VES is based on a check of the morphology of the QRS complexes. This

can be influenced by faults in the signal, position of the electrodes, position type of the heart

or by strongly widened QRS complexes with atrial beats (e.g., in the case of thigh

blockades). With strongly widened QRS complexes and signs of manifestation of fibrillation,

no VES detection is carried out. If there is poor signal quality (especially in the case of signal

4) or in case of doubt concerning the QRS detection (conspicuous features in the Lorenz

plot), you should check R wave detection via the ECG Viewer for plausibility and repeat the

recording if needed.

1 2

Note: If signal is not evaluable, you receive a corresponding note in the report. Please repeat

the recording.

http://th2808ho.dynalias.com/APX_UA/static/signal_quality


Repetition of an SRAclinic® examination due to poor signal quality

In order not to create incorrect results, the analysis is canceled in case of insufficient data quality. This

can be happen for different reasons.

Too many artifacts, and consequently not enough R waves for an adequate calculation.

Too small amplitude of the R waves and insufficient detection of the R waves as a result.

The examination, i.e., the ECG recording, must be repeated for all of these ECGs sent in with poor

quality. There are no additional costs but the additional work for reattaching the electrodes, waiting

time for the patients, etc. can be avoided in most cases.

Generally, all recorders on the market fulfill the necessary standards for a good ECG signal. The

problems mostly arise during attachment of the electrodes. There are two basic rules here, which

almost guarantee a good signal when they are followed.

Skin preparation

Only you can ensure good skin preparation on site; a leaflet from apoplexy medical technologies is

provided to help you in this matter.

Electrodes

In tests, we found that different electrodes under the same conditions otherwise produce significantly

different results in ECG quality. Consequently, the quality of the electrode has a measurable impact on

the signal quality.

To give you an idea of the different quality, we employed a cheap disposable electrode on one

channel and a high-quality disposable electrode on the other channel during the same recording.

Example 1:

Fig. 1 Channel 1

Fig. 2 Channel 2 You can see here that it is very difficult on channel 1 to carry out automatic R wave detection, whereas

channel 2 displays a clean QRS complex.


Example 2:

Fig. 3 Channel 1

Fig. 4 Channel 2 In this example you can see very clearly that occurring and not always avoidable movement

interference impact the ECG signal differently depending on the electrode quality. You can clearly see

that the signal at the cheap electrode is much more susceptible to interference than at the higher

quality electrode.

While you can tolerate longer phases with poor signal quality in conventional long-term ECG

evaluation, SRAclinic® is dependent on automatically detecting the greatest number possible of R

waves in ECG data.

Wissenschaftliche Basis des SRA – Analyseverfahrens

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