Lead system of dynamic ecg
According to BORSAM Biomedical，The lead of dynamic electrocardiogram has been developed from 2 channel and 3 channel to 12 channel (18 channel system). 12 lead can help determine contracts before sexual period, ventricular tachycardia, and bypass, and no clear myocardial ischemia area but according to the American heart association and the Massachusetts institute of technology, the database and the years of clinical practice has proved that system of 12 lead Holter and failed to replace the 3 channel systems (especially in a foreign country), only two records each have emphasize particularly on the choice of mode and system, can complement each other in clinical application. At present, the guiding connections used in dynamic ecg recorder can be divided into the following categories.
Dynamic ecg 3 channel bipolar lead
(1) Frank lead system USES 7 electrodes to form the orthogonal lead X, Y and Z leads of ecg vector diagram. X lead: positive pole (A) 5th intercostal negative pole (I) 5th intercostal Y lead: positive pole (F) left lower limb negative pole (H) Z lead: positive pole (E) anterior midline 5th intercostal negative pole (M) posterior spine 5th intercostal C point: midpoint between A and E in the left anterior chest.
(2) currently, the most commonly used 7 electrodes are MX leads (vertical leads of sternal stalk): the 3 leads selected are CM5 leads (QRS group has the largest amplitude and is most sensitive to ST segment elevation and depression). CM1 lead (can show P wave more clearly); CMaVF leads (can show the ST segment elevation and depression caused by right coronary or left cyclotron vascular lesions), therefore, left ventricular surface + right ventricular surface + lower wall simulation leads have become the best combination of 3-channel bipolar leads most commonly used in dynamic electrocardiogram.
Article 25 the electrode (or 4) the EASI lead system consists of five electrode, lead is used for Frank E, A and I electrodes, plus the S point electrode. The position of point S is the upper central part of the sternum body, and the position of independent electrodes is the right costal arch or any other position (figure).
32 channel bipolar lead + pacing channel on the basis of 3 channel bipolar lead, 1 channel is used for dedicated pacing pulse channel.
Dynamic ecg 12 lead system
According to BORSAM Biomedical，(improved 12-lead) the 12-lead system applied in the dynamic electrocardiogram is derived from the 12-lead system. It USES mathematical derivation method to synthesize the 12-lead system from the ecg data recorded by a few leads, thus forming the derived 12-lead electrocardiogram. The derived ecg can be approximately but not completely equivalent to the standard 12-lead ecg. According to BORSAM Biomedical，EASI lead orthogonal system is the most commonly used in derivative of 12-lead electrocardiogram lead system, on the basis of Frank lead improved (1966 REMason and ILikar put forward the improvement of 12 lead).
The comparison between modified 12-lead and conventional 12-lead ecg is as follows:
(1) the QRS wave electric axis right (Ⅰ lead R/S (1) or less.
(2) Ⅱ, Ⅲ, R wave amplitude increase of aVF lead;
(3) Ⅰ, lead aVL R wave amplitude decreases, You can change both the ST segment and the T wave. In clinical medical application has been validated: EASI lead derivative of 12-lead electrocardiogram and standard 12-lead electrocardiogram between, there is the correlation value, using derivative of lead electrocardiogram detection standard lead electrocardiogram (ecg) in ST segment higher or lower, the average sensitivity and specificity were 89% and 99.5% respectively, but the time of diagnosis to identify breathing and the influence of the position).According to BORSAM Biomedical， By mathematical derivation, the 18-lead ecg can be synthesized from the ecg data recorded by the 12 leads, thus forming the derived 18-lead ecg (with the addition of the posterior wall and the right chest).