ECG

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Re: ECG

مشاركةبواسطة دكتور كمال سيد » الجمعة نوفمبر 07, 2014 7:15 pm

Determining Heart Rate
http://www.learntheheart.com/ecg-review ... eart-rate/



There are two different rates that can be determined on ECGs. The atrial rate is indicated by the frequency of the P waves and the ventricular rate is indicated by the frequency of the QRS complexes.

Normally, the atrial rate should be the same as the ventricular rate in the absence of disease,
however certain conditions, such as third degree AV nodal block or ventricular tachycardia can alter this normal relationship causing “AV dissociation”.
In this setting, the atrial rate (P waves) and ventricular rate (QRS complexes) are at different heart rates.



: One quick and easy way to measure the ventricular rate is

to examine the RR interval (distance between two consecutive R waves) and use a standard scale to find the rate.
If two consecutive R waves are separated by only one large box, then the rate is 300 beats per minute.
i.e. 300 over the number of large boxes
If the R waves are separated by two large blocks, then the ventricular rate is 150 beats per minute.
i.e. 300 over 2 = 150
The scale continues down to show that if two consecutive R waves are separated by 8 large boxes, then the rate is 37 beats per minute.

: Another quick way to calculate the rate is based on the fact that the entire ECG is 10 seconds

So by counting the number of QRS complexes and multiplying by 6, the number per minute can be calculated (since 10 seconds times 6 is 60 seconds or 1 minute

This is a better method when the QRS complexes are irregular (such as during atrial fibrillation) which makes the first method less accurate, since the RR intervals may vary from beat to beat in this setting.

Below are some examples using each method.

: Example 1
Note that the QRS complexes are about five and a half large boxes apart
Referencing the above image it can be determined that the ventricular heart rate is between 50 and 60 beats per minute (300/5=60
This is a full 10 second rhythm strip. There are 9 QRS complexes total
Multiply the number of QRS complexes by 6 and the exact heart rate is 54 beats per minute
There is 1 P wave for each QRS complex and thus the atrial rate is the same

:Example 2
These QRS complexes are exactly three large boxes apart and thus the ventricular heart rate is 100 beats per minute. Now multiple the number of QRS complexes on this strip by 6. This would be 17 x 6 = 102. There is 1 P wave for each QRS complex and thus the atrial rate is the same.

:Example 3
These QRS complexes are less than 2 large boxes apart and thus the heart rate is between 150 and 300. Multiplying the number of QRS complexes by 6 would give 29 x 6 = 174 beats per minute. There is likely 1 P wave for each QRS complex (difficult to see on this strop) and thus the atrial rate is likely the same

Example 4: The below ECG strip shows the irregularly irregular QRS complexes present during atrial fibrillation. Using the first method to determine heart rate would NOT be accurate since the R-R intervals vary significantly. The best way to determine the ventricular heart rate would be to simply count the QRS complexes and multiple by 6 which would be 15 x 6 = 90 beats per minute. The P waves are not able to be identified in atrial fibrillation and it is assumed that the atrial rate is between 400-600 beats per minute.

: Example 5
This ECG strip shows "AV dissociation" meaning the P waves (indicating atrial activity) are at a different rate than the QRS complexes (indicating ventricular activity). This rhythm is actually an accelerated idioventricular rhythm (slow ventricular tachycardia
The atrial rate is indicated by the P waves. There are almost exactly 5 large boxes between P waves indicating an atrial rate of 60 beats per minute.
There are a total of 10 P waves on this strip (difficult to see some of them as they are intermittently buried in the QRS complexes) and 10 x 6 = 60 confirming the first method.
There are just more than 4 big boxes between each QRS complexes and thus the ventricular rate is between 60 and 75. Since there is a total of 11 QRS complexes in this full 10 second strip, the actual ventricular rate is 11 x 6 = 66 beats per minute.

http://www.learntheheart.com/ecg-review ... eart-rate/
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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » السبت نوفمبر 08, 2014 6:45 am

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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » السبت نوفمبر 08, 2014 7:11 am

Determining Rhythm
http://www.learntheheart.com/ecg-review ... ng-rhythm/

The rhythm is either sinus rhythm or not sinus rhythm
Sinus rhythm refers to the origination of the electrical activity coming from the sinus node (SA node or sinoatrial node). This results in an upright P wave in lead II on the ECG
Sinus rhythm means a normal heart beat, both with respect to the heart rate and rhythm. Heart rate will fall between 60 and 100 beats per minute. The shape of the electrocardiogram (EKG) tracing will exhibit certain key attributes to be considered normal, as discussed below.

If there is a P wave before every QRS complex and it has a "sinus morphology", then “normal sinus rhythm” or “NSR” is said to be present
A sinus morphology is an upright P wave in lead II and biphasic (up and down) in lead V1
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If the P wave has a different morphology than the typical sinus morphology, then it is termed "ectopic" simply meaning coming from somewhere other than the sinus node
Ectopic atrial rhythms (including atrial tachycardia), multifocal atrial tachycardia and junctional rhythms all have P waves that are not of sinus morphology and will be reviewed in detail later.

The second strip below shows an ectopic atrial rhythm. Note that the P wave is down in lead II and only up (not biphasic) in lead V1
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Sinus tachycardia
If there is sinus rhythm and the heart rate is greater than 100, then “sinus tachycardia” is present
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Sinus tachycardia (also colloquially known as sinus tach or sinus tachy) is a sinus rhythm with an elevated rate of impulses, defined as a rate greater than 100 beats/min (bpm) in an average adult. The normal resting heart rate in the average male adult ranges from 60–100 bpm and women 60-90bpm.
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Sinus Bradycardia ECG
Sinus bradycardia can be the result of many things including good physical fitness, medications, and some forms of heart block. "Sinus" refers to the sinus node, the heart's natural pacemaker which creates the normal regular heartbeat. "Bradycardia" means that the heart rate is slower than normal.
If the there is sinus rhythm and the heart rate is less than 60, then “sinus bradycardia” is present
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Sinus bradycardia is a sinus rhythm with a rate that is lower than normal. In humans, bradycardia is generally defined to be a rate of under 60 beats per minute.

If there are no P waves present or the P wave morphology is not normal, then the exact rhythm must be determined.
Multiple other arrhythmias exist and include atrial fibrillation, atrial flutter, and ventricular rhythms such as ventricular tachycardia or ventricular fibrillation. These are discussed in detail in the ECG criteria review sections.

Note that when “AV dissociation” is present as previously described (complete heart block or ventricular tachycardia), there may not be a P wave before every QRS complex, however as long as the P wave is upright in lead II, sinus rhythm is still said to be present.
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Re: ECG

مشاركةبواسطة دكتور كمال سيد » الأربعاء أكتوبر 31, 2018 7:39 pm

The Electrocardiogram (EKG or ECG) ANIMATION

image description
https://www.getbodysmart.com/circulatory-system/ekg
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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 7:39 pm

AXIS DEVIATION
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Hexaxial Reference System – relationship between QRS axis and frontal leads of the ECG.

Right Axis Deviation = QRS axis greater than +90°

Normal Axis = QRS axis between -30° and +90°
Left Axis Deviation = QRS axis less than -30°
Extreme Axis Deviation = QRS axis between -90° and 180° (AKA “Northwest Axis”)

How to recognise right axis deviation
Three Lead analysis

QRS is POSITIVE (dominant R wave) in Lead II, Lead III and aVF
QRS is NEGATIVE (dominant S wave) in Lead I
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RAD: leads II, III and aVF are POSITIVE; Leads I and aVL are NEGATIVE

Causes

Left posterior fascicular block
Lateral myocardial infarction
Right ventricular hypertrophy
Acute lung disease (e.g. Pulmonary Embolus)
Chronic lung disease (e.g. COPD)
Ventricular ectopy
Hyperkalaemia
Sodium-channel blocker toxicity
WPW syndrome
Normal in children or thin adults with a horizontally positioned heart
https://litfl.com/right-axis-deviation-rad-ecg-library/

Left Axis Deviation (LAD)
Left Axis Deviation = QRS axis less than -30°.

Normal Axis = QRS axis between -30° and +90°
Right Axis Deviation = QRS axis greater than +90°
Extreme Axis Deviation = QRS axis between -90° and 180° (AKA “Northwest Axis”)

How to recognise left axis deviation
Three Lead analysis

QRS is POSITIVE (dominant R wave) in Lead I
QRS is NEGATIVE (dominant S wave) in leads II, III and aVF
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Left Axis Deviation: leads I and aVL are positive; leads II and aVF are negative

Causes of LAD

Left anterior fascicular block
Left bundle branch block
Left ventricular hypertrophy
Inferior MI
Ventricular ectopy
Paced rhythm
Wolff-Parkinson White syndrome

https://litfl.com/left-axis-deviation-lad-ecg-library/


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Recall that the axis can be considered in terms of four quadrants, with lead I oriented at 0°, and aVF oriented at +90°. An ECG with the QRS axis oriented to the quadrant between 0° and 90° is said to be normal.
An ECG with the QRS axis oriented to the quadrant between -1° and -90° is said to have left axis deviation.
An ECG with the QRS oriented to the quadrant between +91° and 180° is said to have right axis deviation.
An ECG with the QRS oriented to the quadrant between -91° and -180° is said to have an indeterminate axis because one cannot tell if it represents right or left axis deviation
https://meds.queensu.ca/central/assets/ ... block.html
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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 9:47 pm

Bundle Branch Block

A bundle branch block can be diagnosed when the duration of the QRS complex on the ECG exceeds 120 ms.
A right bundle branch block typically causes prolongation of the last part of the QRS complex, and may shift the heart's electrical axis slightly to the right.

Bundle branch block is a condition in which there's a delay or blockage along the pathway that electrical impulses travel to make your heart beat. It sometimes makes it harder for your heart to pump blood efficiently through your body.
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The delay or blockage can occur on the pathway that sends electrical impulses either to the left or the right side of the bottom chambers (ventricles) of your heart.

Bundle branch block might not need treatment. When it does, treatment involves managing the health condition, such as heart disease, that caused bundle branch bloc

Symptoms

In most people, bundle branch block doesn't cause symptoms. Some people with the condition don't know they have a bundle branch block.

Signs and symptoms in people who have them might include:

Fainting (syncope)
Feeling as if you're going to faint (presyncope)

Causes can include:
Left bundle branch block

Heart attacks (myocardial infarction)
Thickened, stiffened or weakened heart muscle (cardiomyopathy)
A viral or bacterial infection of the heart muscle (myocarditis)
High blood pressure (hypertension)

Right bundle branch block

A heart abnormality that's present at birth (congenital) — such as atrial septal defect, a hole in the wall separating the upper chambers of the heart
A heart attack (myocardial infarction)
A viral or bacterial infection of the heart muscle (myocarditis)
High blood pressure in the pulmonary arteries (pulmonary hypertension)
A blood clot in the lungs (pulmonary embolism)

Risk factors

Risk factors for bundle branch block include:

Increasing age. Bundle branch block is more common in older adults than in younger people.
Underlying health problems. Having high blood pressure or heart disease increases your risk of having bundle branch block.

Complications

The main complication of bundle branch block, right or left, is to progress to a complete block of the electric conduction from the upper chambers of the heart to the lower. This can slow your heart rate, which can cause fainting and lead to serious complications and abnormal heart rhythms.

People who have a heart attack and develop a left bundle branch block have a higher chance of complications, including sudden cardiac death, than do people who don't develop the condition after a heart attack.

Because bundle branch block affects the electrical activity of your heart, it can sometimes complicate the accurate diagnosis of other heart conditions, especially heart attacks, and lead to delays in proper management of those problems.
https://www.mayoclinic.org/diseases-con ... c-20370514
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Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 9:56 pm

Diagnosis

If you have a right bundle branch block and you're otherwise healthy, you might not need a full evaluation. If you have a left bundle branch block, you will need a full evaluation.

Tests that can be used to diagnose a bundle branch block or its causes include:

Electrocardiogram.
This records the electrical impulses in your heart through wires attached to the skin on your chest and other places on your body. Abnormalities might indicate a bundle branch block, as well as which side is being affected.
Echocardiogram.
This test uses sound waves to provide detailed images of the heart's structure and shows the thickness of your heart muscle and whether your heart valves are moving normally. It can pinpoint a condition that caused the bundle branch block.

Treatment

Most people with bundle branch block are symptom-free and don't need treatment.

However, if you have a heart condition causing bundle branch block, treatment might involve medications to reduce high blood pressure or lessen the effects of heart failure.

Additionally, depending on your symptoms and whether you have other heart problems, your doctor might recommend:

A pacemaker.
If you have bundle branch block and a history of fainting, your doctor might recommend a pacemaker. This compact device is implanted under the skin of your upper chest (internal pacemaker) with two wires that connect to the right side of your heart. The pacemaker provides electrical impulses when needed to keep your heart beating regularly.

Cardiac resynchronization therapy.
Also known as biventricular pacing, this procedure is similar to having a pacemaker implanted. However, with this procedure, there's a third wire that's connected to the left side of the heart so the device can keep both sides in proper rhythm.

This therapy, which is meant to improve the coordination of both lower chambers of the heart so that they contract at the same time, is used in people with low pumping function and a bundle branch block.

https://www.mayoclinic.org/diseases-con ... c-20370518
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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 10:07 pm

Left Bundle Branch Block (LBBB) ECG Review
https://www.healio.com/cardiology/learn ... bbb-review

The ECG criteria for a left bundle branch block include:

QRS duration greater than 120 milliseconds
Absence of Q wave in leads I, V5 and V6
Monomorphic R wave in I, V5 and V6
ST and T wave displacement opposite to the major deflection of the QRS complex

A simple way to diagnose a left bundle branch in an ECG with a widened QRS complex (> 120 ms) would be to look at lead V1.
If the QRS complex is widened and downwardly deflected in lead V1, a left bundle branch block is present.
If the QRS complex is widened and upwardly deflected in lead V1, a right bundle branch block is present.
The image below shows the typical findings of a left bundle branch block in the precordial ECG leads.
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Note: If the QRS duration is 100 to 119 ms with criteria 2, 3 and 4 of the above, an incomplete LBBB is present.

ECG Examples of LBBB
https://www.healio.com/cardiology/learn ... bbb-review
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اشترك في: الخميس إبريل 04, 2013 10:28 pm

Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 10:22 pm

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Re: ECG

مشاركةبواسطة دكتور كمال سيد » الاثنين نوفمبر 12, 2018 10:25 pm

Right bundle branch block
https://www.healio.com/cardiology/learn ... anch-block

The ECG criteria for a right bundle branch block include:

QRS duration of > 120 milliseconds
rsR' "bunny ear" pattern in precordial leads
Slurred S waves in leads I, V5, and V6.

Remember that T wave inversions and ST segment depression is normal in leads V1 - V3 in the presence of a RBBB, this technically myocardial ischemia can not be easily determined in these leads.
However, unlike in the presence of a left bundle branch block, myocardial ischemia and infarction can easily be detected on ECG when a RBBB is present (see anterior and inferior wall MI examples).
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