ECG: UNDERSTANDING ECG: UNDERSTANDING ACCELERATED ACCELERATED CONDUCTIONCONDUCTION

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

[Pune][Pune]Professor & HOD, Dept. of MedicineProfessor & HOD, Dept. of Medicine

Teaching Medicine, Materia & RepertoryTeaching Medicine, Materia & Repertory

Lal Bahadur Shastri Homœopathic Medical Lal Bahadur Shastri Homœopathic Medical College, Bhopal – 26 (MP)College, Bhopal – 26 (MP)

EmailEmail: post.krishnendu2010@ymail.com: post.krishnendu2010@ymail.com

INTRODUCTIONINTRODUCTION

There are 02 types of accelerated There are 02 types of accelerated

conductions from the atrium to the conductions from the atrium to the

ventricles; viz.ventricles; viz.

Wolff-Parkinson-White (WPW) Wolff-Parkinson-White (WPW)

Syndrome / Pre-excitation Syndrome.Syndrome / Pre-excitation Syndrome.

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

WPW SYNDROMEWPW SYNDROME

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

Mahaim fibes – which goes from Bundle of Mahaim fibes – which goes from Bundle of

His to Ventricular Septum. The pre-His to Ventricular Septum. The pre-

excitation of ‘excitation of ‘Bundle of KentBundle of Kent’ is called WPW ’ is called WPW

Syndrome.Syndrome.

The atrial impulse passes through the The atrial impulse passes through the

normal path of conduction and also through normal path of conduction and also through

the anterior intra-nodal fibre [Bachmann’s the anterior intra-nodal fibre [Bachmann’s

fibre / Bundle of Kent], simultaneously.fibre / Bundle of Kent], simultaneously.

CLASSIFICATION OF CLASSIFICATION OF WPW SYNDROMEWPW SYNDROME

WPW Syndrome is of WPW Syndrome is of 0202 types ---- types ----

Type AType A: where excitation travels along : where excitation travels along Left accessory pathway – giving rise to Left accessory pathway – giving rise to RVH / RBBB. RVH / RBBB.

Type BType B: where excitation travels along : where excitation travels along Right lateral accessory pathways – giving Right lateral accessory pathways – giving rise to LBBB. If it is associated with rise to LBBB. If it is associated with Cyanotic CHD – Ebstein’s Anomaly is Cyanotic CHD – Ebstein’s Anomaly is diagnosed.diagnosed.

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 of Appearance of -wave / slurred upstroke of QRS.-wave / slurred upstroke of QRS.

Normal P-wave axis.Normal P-wave axis.

CAUSES OF WPW CAUSES OF WPW SyndromeSyndrome

Normal individuals.Normal individuals.

Myocardial Infarction.Myocardial Infarction.

Acute Rheumatic Fever.Acute Rheumatic Fever.

CHD – Ebstein’s Anomaly.CHD – Ebstein’s Anomaly.

Cardiac catheterization / Surgical Cardiac catheterization / Surgical manipulation of Heart.manipulation of Heart.

Hypertrophic Sub-aortic Stenosis.Hypertrophic Sub-aortic Stenosis.

Idiopathic Cardiomyopathy.Idiopathic Cardiomyopathy.

Thyrotoxicosis.Thyrotoxicosis.

WPW SYNDROME WITH WPW SYNDROME WITH ATRIAL FIBRILLATION ATRIAL FIBRILLATION

Irregularly irregular, wide complex tachycardia.Irregularly irregular, wide complex tachycardia.Impulses from the atria are conducted to the ventricles via Impulses from the atria are conducted to the ventricles via either either

both the AV node and Accessory pathway producing a both the AV node and Accessory pathway producing a broad fusion complex.broad fusion complex.

or just AV node producing a narrow complex (without or 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-R People who develop this rhythm and have very short R-R intervals are at higher risk of VF.intervals are at higher risk of VF.

LGL SyndromeLGL Syndrome

James Accesory Tract / Bundle of James by-pass James Accesory Tract / Bundle of James by-pass

the upper part of the AV node. The pre-the upper part of the AV node. The pre-

excitation of the ‘excitation of the ‘Bundle of JamesBundle of James’ is called LGL ’ is called LGL

Syndrome.Syndrome.

The artrial impulse preferentially passes The artrial impulse preferentially passes

through the posterior intra-nodal fibre [Thorel’s through the posterior intra-nodal fibre [Thorel’s

fibre / Bundle of James] and conducted to His fibre / Bundle of James] and conducted to His

Bundle.Bundle.

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

Supra-ventricular arrhythmias, ventricular Supra-ventricular arrhythmias, ventricular

tachycardia & Ventricular fibrillation.tachycardia & Ventricular fibrillation.

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.

No No -wave.-wave.

LGL SYNDROME WITH LGL SYNDROME WITH ATRIAL FIBRILLATIONATRIAL FIBRILLATION

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

No No -wave-wave..

REFERENCESREFERENCES

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

April, 1995; Current Book International].April, 1995; Current Book International].

2.2. Ganong, Dr. William F. – Review of Medical Ganong, Dr. William F. – Review of Medical

Physiology (22Physiology (22NDND edition, 2005; McGraw Hill). edition, 2005; McGraw Hill).

3.3. Mehta, Dr. P. J. – Understanding ECG Mehta, Dr. P. J. – Understanding ECG

[Reprint 6[Reprint 6THTH edition, 2008; The National Book edition, 2008; The National Book

Depot].Depot].

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