7. Evaluation of the ECG recordings

The Cardiax system gives you the possibility to evaluate the ECG recordings subsequently, independently from the taking of the recording.

The 12 lead ECG recordings, indicated 'Precordial' can be automatically evaluated. The automatic evaluation produces the averaged, the so called median beats from the recording, performs the rhythm and contour analysis, prepares the table of the parameters and gives a textual diagnosis proposal.

If the selected recording is incomplete (the ECG sign does not appear on a channel) or one of the leads is too noisy, an error message appears, and the program does not perform the automatic evaluation.

7.1 Manual evaluation in the 'ECG ruler'

The median calculation determines the most characteristic beat of the leads, the interpretation displays these medians in 12 channels, calculates the time and amplitude values necessary for the rhythm and contour analysis, draws the rhythm curve and displays a table of the diagnostically important parameters. On the basis of the rhythm and morphologic evaluation the program suggests the diagnosis for adults (over 15 years of age) and for children (2-14 years of age).

7.2 Median calculation

The upper table (on the right) shows the global parameters relating to the whole of the analysed curve, the lower table displays the more specific parameters relating to the selected lead. The first actual lead is 'I', modify it from the menu or click with the mouse on the appropriate median cell. The corresponding median curve will appear in the graphic part of the screen in magnification, with 20 mm/mV amplitude and in 200 mm/sec time resolution.

Markers show on the magnified median every place of the global calculation points, which are calculated with every projection of the ECG curve, therefore their place is unchanged on every lead:

• PB, PE - beginning, end of the P wave;
• B, J - beginning, end of the QRS complex;
• STE - end of the ST segment;
• TE - end of the T wave.

• STE - the middle point of the interval between the global cusp of the T wave and the J point
• J80 (J60) - 80 msec from the J point or in case of HR > 100, 60 msec.

7.3 Parameters and diagnosis

The Parameters item displays the parameters of every lead system in a comprehensive table. The upper part of the table contains the global parameters relating to the whole of the recording, the lower part contains the specific parameters of each lead system.

The Automatic diagnosis provides a suggested rhythm and clinical diagnosis based on the evaluation of the morphology of the recorded ECG, to assist in interpretation by the physician. ANY FINAL DIAGNOSIS MUST ALWAYS BE MADE BY A QUALIFIED PHYSICIAN. The physician’s diagnosis can be added by opening the Edit diagnosis item, where the suggested Automatic diagnosis text will be displayed.

Patient AGE must be entered by the user for the Automatic diagnosis function to operate: (children 1-15 years, adults 16+ years). Without an entry for patient AGE in the patient card, a warning appears.

The first statement of the diagnosis contains the length of the ECG recording used for analysis, the total number of the beats analyzed, and statements that refer to the normal (non-pathological) attributes of the ECG. Following this is a list of ECG alterations classified as pathological. This list also includes findings in which pathological ECG findings are present but in which ECG parameters do not reach threshold values to make a diagnosis. The diagnosis also lists non-characteristic deviations that cannot be clearly related to a pathological ECG alteration but which should be further evaluated.