Ecg: Understanding Accelerated Conduction

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ECG: UNDERSTANDINGECG: UNDERSTANDING

ACCELERATEDACCELERATEDCONDUCTIONCONDUCTION

Dr. Krishnendu MaityDr. Krishnendu MaityBHMS [Calcutta] MD (Hom. Repertory)BHMS [Calcutta] MD (Hom. Repertory)

[Pune][Pune]

Associate Professor & HOD I/c, Dept. ofAssociate Professor & HOD I/c, Dept. of

MedicineMedicine

Teaching Medicine, Materia & RepertoryTeaching Medicine, Materia & Repertory

Lal Bahadur Shastri Homopathic MedicalLal Bahadur Shastri Homopathic Medical


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INTRODUCTIONINTRODUCTION

There are 02 types of accelerated conductions fromThere are 02 types of accelerated conductions from

the atrium to the ventricles; viz.the atrium to the ventricles; viz.

Wolff-Parkinson-White (WPW) Syndrome / Pre-Wolff-Parkinson-White (WPW) Syndrome / Pre-

excitation Syndrome.excitation Syndrome.

Lown-Ganong-Levine (LGL) Syndrome.Lown-Ganong-Levine (LGL) Syndrome.


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WPW SYNDROMEWPW SYNDROME

Bundle of Kent by-pass the AV node or byBundle of Kent by-pass the AV node or by

Mahaim fibes which goes from Bundle of His toMahaim fibes which goes from Bundle of His to

Ventricular Septum. The pre-excitation of Ventricular Septum. The pre-excitation of BundleBundle

of Kentof Kent is called WPW Syndrome. is called WPW Syndrome.

The atrial impulse passes through the normalThe atrial impulse passes through the normal

path of conduction and also through the anteriorpath of conduction and also through the anterior

intra-nodal fibre [Bachmanns fibre / Bundle ofintra-nodal fibre [Bachmanns fibre / Bundle of

Kent], simultaneously.Kent], simultaneously.


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CLASSIFICATION OFCLASSIFICATION OF

WPW SYNDROMEWPW SYNDROMEWPW Syndrome is ofWPW Syndrome is of0202 types ----types ----

Type ATy

pe A: where excitation travels along Left: where excitation travels along Left

accessory pathway giving rise to RVH / RBBB.accessory pathway giving rise to RVH / RBBB.Type BTy

pe B: where excitation travels along Right: where excitation travels along Right

lateral accessory pathways giving rise tolateral accessory pathways giving rise to

LBBB. If it is associated with Cyanotic CHD LBBB. If it is associated with Cyanotic CHD

Ebsteins Anomaly is diagnosed.Ebsteins Anomaly is diagnosed.


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ECG OF WPW SyndromeECG OF WPW Syndrome

Short P-R interval [less than 0.12 sec.].Short P-R interval [less than 0.12 sec.].

Wide QRS complex.Wide QRS complex.

Appearance ofAppearance of -wave / slurred upstroke of QRS.-wave / slurred upstroke of QRS.Normal P-wave axis.Normal P-wave axis.


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CAUSES OF WPWCAUSES OF WPWSyndromeSyndrome

Normal individuals.Normal individuals.

Myocardial Infarction.Myocardial Infarction.

Acute Rheumatic Fever.Acute Rheumatic Fever.

CHD Ebsteins Anomaly.CHD Ebsteins Anomaly.

Cardiac catheterization / SurgicalCardiac catheterization / Surgical

manipulation of Heart.manipulation of Heart.

Hypertrophic Sub-aortic Stenosis.Hypertrophic Sub-aortic Stenosis.Idiopathic Cardiomyopathy.Idiopathic Cardiomyopathy.

Thyrotoxicosis.Thyrotoxicosis.


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WPW SYNDROME WITHWPW SYNDROME WITH

ATRIAL FIBRILLATIONATRIAL FIBRILLATION

Irregularly irregular, wide complex tachycardia.Irregularly irregular, wide complex tachycardia.

Impulses from the atria are conducted to the ventricles viaImpulses from the atria are conducted to the ventricles viaeithereither

both the AV node and Accessory pathway producing aboth the AV node and Accessory pathway producing abroad fusion complex.broad fusion complex. or just AV node producing a narrow complex (withoutor just AV node producing a narrow complex (without --

wave).wave). or just Accessory pathway producing a very broad 'pure'or just Accessory pathway producing a very broad 'pure' --

wave.wave.

People who develop this rhythm and have very short R-RPeople who develop this rhythm and have very short R-Rintervals are at higher risk of VF.intervals are at higher risk of VF.


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LGL SyndromeLGL Syndrome

James Accesory Tract / Bundle of James by-pass the upperJames Accesory Tract / Bundle of James by-pass the upperpart of the AV node. The pre-excitation of the part of the AV node. The pre-excitation of the Bundle ofBundle of

JamesJames is called LGL Syndrome. is called LGL Syndrome.

The artrial impulse preferentially passes through theThe artrial impulse preferentially passes through the

posterior intra-nodal fibre [Thorels fibre / Bundle ofposterior intra-nodal fibre [Thorels fibre / Bundle ofJames] and conducted to His Bundle.James] and conducted to His Bundle.

Pateints of this syndrome are prone to develop Supra-Pateints of this syndrome are prone to develop Supra-

ventricular arrhythmias, ventricular tachycardia &ventricular arrhythmias, ventricular tachycardia &

Ventricular fibrillation.Ventricular fibrillation.


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ECG OF LGL SyndromeECG OF LGL Syndrome

Short P-R interval.Short P-R interval.

Normal QRS complex.Normal QRS complex.

Normal T-wave.Normal T-wave.

NoNo -wave.-wave.


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LGL SYNDROME WITHLGL SYNDROME WITH

ATRIAL FIBRILLATIONATRIAL FIBRILLATION

Short PR interval [less than 3 small squares].Short PR interval [less than 3 small squares].

NoNo -wave-wave..


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REFERENCESREFERENCES

1.1. Das, Dr. P. C. Textbook of Medicine [Reprint April,Das, Dr. P. C. Textbook of Medicine [Reprint April,

1995; Current Book International].1995; Current Book International].

2.2. Ganong, Dr. William F. Review of Medical PhysiologyGanong, Dr. William F. Review of Medical Physiology

(22(22NDND

edition, 2005; McGraw Hill).edition, 2005; McGraw Hill).

3.3. Mehta, Dr. P. J. Understanding ECG [Reprint 6Mehta, Dr. P. J. Understanding ECG [Reprint 6THTH

edition, 2008; The National Book Depot].edition, 2008; The National Book Depot].


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THANKS TO ALL ------THANKS TO ALL ------

Ecg: Understanding Accelerated Conduction

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