ECG types


source from http://thehealthgurus.info/

• The electrodes carry information of the heart top, bottom and lateral side of the heart
• Eithoven Triangle:
• First lead: 1 2 3
• The heart is an organ tridimencionall
• ECG quick painless and noninvasive tool
• A shunt is formed by two electrodes

HEART LEADS

2 types: Standard and precordial

THE 12-lead ECG standard is explained as follows:

1. Limb leads (classical) total 6,

3 bipolar (I II III) and

the pole. (AVR AVF and AVL)

2. Or precordial chest leads (V1-V2-V3-V4-V5-V6)

STANDARD LEADS

These only evaluate the frontal plane of the heart

To the extent that action potentials in the heart come to a positive electrode give positive vibes. As will move in the opposite direction negative waves.

BIPOLAR: D1, D2, D3

Eithoven leave the triangle (above)

They have two poles + and -

UNIPOLAR

Emmanuel Goldberg introduced the augmented leads of the extremities. Bone the unipolar

The low voltage unipolar Captan then came to the voltage increase

Referrals are also known as unipolar or expanded

AVR voltage amplitude = right arm

AVF = ampllitud voltage standing arm

AVL = voltage amplitude right arm

HEX SHAFT AXIAL

This axis is the sum of all the voltages of the standard leads, sum that will give us the direction that target the summation of action potentials that pass through the heart (vector in the direction of force)

The heart is the center of the standard leads

• All vectors that hexa graphing the axial axis between -30 and 110 is normal.
• All that plot between – 30 and -90 will have an orientation to the left and will be negative
• All that is between 110 and (+ -) 180 is positive, being in the right quadrant or right orientation will have
• All that is between -90 and (+ -) 180 on the dial will be indeterminate

Precordial

They are so called because they are in the precordium, on the heart

The precordial leads are V1, V2 V3 V4 V5 V6

• V1 and V2-voltage measure right heart
• V3 and V4-measure voltage or septum septum
• V5 and V6-voltage measured left heart

In this picture we see the 12-lead:

Use of ECG for Diagnostic Purposes



diagnostic information can be obtained from the ECG waveform, by analysis of the amplitude and relative timing of the various segments. In general, cardiac muscle damage, or infarcts, are correlated with loss of amplitude. Abnormal heart rates (arrhythmias) can be observed and treated; for examples slow rhythms (bradycardia) can be treated with stimulants or a pacemaker whilst in the case of fast (tachycardia) depressants can be prescribed. Ectopic beats are beats which originate from a region of the heart other than the SA node. An ectopic beat in the ventricle causes an extra R−wave, indicative of a premature ventricular contraction (PVC).

These abnormal conditions are usually identified by one of two means:

• Ambulatory monitoring for up to 24 hours of patients who have been identified as being at risk of heart attacks. Data compression techniques (eg beat−to−beat interval histograms) are often used although advances in memory technology is reducing the need for these.

•  Exercise stress ECGs in which the patient is taken close to maximum heart rate by exercising, for example on a tread mill. Changes in the ECG waveform during this process give the cardiologist indications as to the efficiency and capacity of the heart’s pumping action. PVCs may only occur when the body is under physical stress, as this makes demands for higher cardiac output. Exercise testing can also be used to assess the effectiveness of therapeutic and surgical treatments.

A more specialised application of ECG analysis is the detection of foetal distress prior to and during labour. An additional problem here is the separation of the maternal and foetal ECGs (adaptive filtering techniques are usually required in addition to careful positioning of the ecletrodes).

All the above applications involve the analysis of the ECG waveform and the extraction of

various features of the waveform. In each case, the heart rate provides information of value

and needs to be calculated. There are two types of heart rate meters (also known as

cardiotachometers):

• the averaging heart rate meter which calculates the average heart rate from a count or estimate of the number of beats over a period of time.

• the beat−to−beat heart rate meter which computes the reciprocal of the time interval between two consecutive heart beats and updates the information with each heart beat.( this method will be use in this project )

ECG

The heart is one of the most vital organs within the human body. It acts as a pump that circulates oxygen and nutrient carrying blood around the body in order to keep it functioning. The circulated blood also removes waste products generated from the body to the kidneys. When the body is exerted the rate at which the heart beats will vary proportional to the amount of effort being exerted. By detecting the voltage created by the beating of the heart, its rate can be easily observed and used for a number of health purposes.An electrocardiogram (ECG) is a graphical trace of the voltage produced by the heart. A sample trace of a typical ECG output for a single beat is shown below. There are 5 identifiable features in an ECG trace which corresponds to different polarization stages that makes up a heartbeat. These deflections are denoted by the letters P, Q, R, S and T.