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8/8/2019 Basic EKG yong 69

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Basic EKGElectrical Physiology
http://history.go%28-1%29/http://history.go%28-1%29/


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EKG, Nerve conduction,BP&Aortic pressure


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AO = aortic valve opening;AC = aortic valve closing;LV = left ventricle;LA = left atrium;

RV = right ventricle;RA = right atrium; MO = mitral valve opening.The phases of the cardiac cycle are atrial systole (a), isometric contraction (b), maximal ejection (c),reduced ejection (d), protodiastolic phase (e), isometric relaxation (f), rapid inflow (g), and diastasis, or slow LV filling (h). For illustrative purposes, time intervals between valvular events have been modified,and the z point has been prolonged.

EKG


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Remark

....

PR interval

Normal QRS complex=

QT interval

RR interval

Basic EKG interpretation1.RateRegular rate

If Irregular rate

2.Rhythm Regular or Irregular

Arrhythmia


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Theory of Tachyarrhythmia-Abnormal impulse formation

-Enhance normal automaticity: auto phase 4 depolarizationSA,AV node,His Purkinje

** resting membrane potential,threshold potential,slope of phase 4 depol

-Abnormal automaticityMyocardial [Atrial &Ventricle] irritability generate impulse

-Trigger activity-Early after depolarization

ex. Torsade de point[Polymorphic ventricular tachycardia]Prolong QT syndrome,brady or phase dependent antiarrhythemic drug

-Delay after depolarizationex. digitalis toxicity

-Abnormal impulse conductionReentry

-Classical reentryslow conduction zone[unidirectional block]

-Random reentry:AFBradyarrhythmia

- SA block ,Sinus pause ,sinus arrest and Sickness Sinus Syndrome


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-AV block


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-Bundle branch block

3.Axis

Note


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4.Chamber enlagementAtrium

Note

Ventricle


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-InjuryST segment change

ST depressed & ST elevated

Note


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Schema of the shape of ST-segment elevation. (A),Concave type. (B), Straight type. (C) , Convex type.


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Reciprocal change=.

Region of ST Elevation Region of ST Depression Anterior (leads V1-V4) Inferior (true posterior)

Inferior (leads II, III, aVF) Anterior (leads V1-V3 or lateral lead 1.aVL)Lateral ( leads I, aVF, V5,

V6) Inferior ( leads II, III, aVF)

True Posterior Anterior (leads V1-V3)-IschemiaInverted T Ischemia is suggested by symmetric T wave inversion, especially when seen in

two or more leads of a group

-InfarctionQ wave pathological Q wave

1. Upsloping ST segment depression .2. ST segment convex depression .3. ST segment horizontal depression .

It should be measured at the Y point,

at 80 ms from the J point (J80).4. ST segment downward depression ..5. ST segment elevation . It should bemeasured at the Y point, at 40 ms fromthe J point (J40).


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Vascular supply of The Heart

Blood supply to Cardiac wall


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Anatomical relationship of leads

Inferior wall Leads II, III, and aVF Anteroseptal wall Leads V1 to V4 [Septal wall V1-V2,Anterior wall V3-

V4] Lateral wall Leads I, aVL, V5, and V6

Non-standard leads

Right ventricle Right sided chest leads V1R to V6RPosterior wall Leads V7 to V9


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. Posterior wall infarction Isolated posterior infarctionwith no associated inferior changes (note ST segmentdepression in leads V1 to V3)

The ECG does not have a lead that faces directly to the posterior wall of the

heart. However, abnormalities of depolarisation will cause reciprocal or mirror changes in the anterior leads. The important leads are V1,2,3 of which V2 isthe most important. The 3 classical changes to be sought are:

1.A tall and slightly wide R wave.2.There should be, in theory, elevation of the ST segment but in

practice it is usually very slight if at all.3.There must be a high T wave in V2. This is essential and without it the diagnosis is unsafe.

Ischemic pattern

Abnormal EKG Electrolyte imbalance


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