ECG: UNDERSTANDING ACCELERATED CONDUCTION

1
ECG UNDERSTANDING ACCELERATED CONDUCTION

• Dr. Krishnendu Maity
• BHMS Calcutta MD (Hom. Repertory) Pune
• Professor HOD, Dept. of Medicine
• Teaching Medicine, Materia Repertory
• Lal Bahadur Shastri Homœopathic Medical College,
  Bhopal 26 (MP)
• Email post.krishnendu2010_at_ymail.com

2
(No Transcript)
3
INTRODUCTION

• There are 02 types of accelerated conductions
  from the atrium to the ventricles viz.
• Wolff-Parkinson-White (WPW) Syndrome /
  Pre-excitation Syndrome.
• Lown-Ganong-Levine (LGL) Syndrome.

4
WPW SYNDROME

• Bundle of Kent by-pass the AV node or by Mahaim
  fibes which goes from Bundle of His to
  Ventricular Septum. The pre-excitation of Bundle
  of Kent is called WPW Syndrome.
• The atrial impulse passes through the normal path
  of conduction and also through the anterior
  intra-nodal fibre Bachmanns fibre / Bundle of
  Kent, simultaneously.

5
CLASSIFICATION OF WPW SYNDROME

• WPW Syndrome is of 02 types ----
  
• Type A where excitation travels along Left
  accessory pathway giving rise to RVH / RBBB.
• Type B where excitation travels along Right
  lateral accessory pathways giving rise to LBBB.
  If it is associated with Cyanotic CHD Ebsteins
  Anomaly is diagnosed.

6
ECG OF WPW Syndrome

• Short P-R interval less than 0.12 sec..
• Wide QRS complex.
• Appearance of ?-wave / slurred upstroke of QRS.
• Normal P-wave axis.

7
CAUSES OF WPW Syndrome

• Normal individuals.
• Myocardial Infarction.
• Acute Rheumatic Fever.
• CHD Ebsteins Anomaly.
• Cardiac catheterization / Surgical manipulation
  of Heart.
• Hypertrophic Sub-aortic Stenosis.
• Idiopathic Cardiomyopathy.
• Thyrotoxicosis.

8
WPW SYNDROME WITH ATRIAL
FIBRILLATION

• Irregularly irregular, wide complex tachycardia.
• Impulses from the atria are conducted to the
  ventricles via either
• both the AV node and Accessory pathway producing
  a broad fusion complex.
• or just AV node producing a narrow complex
  (without ?-wave).
• or just Accessory pathway producing a very broad
  'pure' ?- wave.
• People who develop this rhythm and have very
  short R-R intervals are at higher risk of VF.

9
LGL Syndrome

• James Accesory Tract / Bundle of James by-pass
  the upper part of the AV node. The pre-excitation
  of the Bundle of James is called LGL Syndrome.
• The artrial impulse preferentially passes through
  the posterior intra-nodal fibre Thorels fibre /
  Bundle of James and conducted to His Bundle.
• Pateints of this syndrome are prone to develop
  Supra-ventricular arrhythmias, ventricular
  tachycardia Ventricular fibrillation.

10
ECG OF LGL Syndrome

• Short P-R interval.
• Normal QRS complex.
• Normal T-wave.
• No ?-wave.

11
LGL SYNDROME WITH ATRIAL
FIBRILLATION

• Short PR interval less than 3 small squares.
• No ?-wave.

12
REFERENCES

• Das, Dr. P. C. Textbook of Medicine Reprint
  April, 1995 Current Book International.
• Ganong, Dr. William F. Review of Medical
  Physiology (22ND edition, 2005 McGraw Hill).
• Mehta, Dr. P. J. Understanding ECG Reprint 6TH
  edition, 2008 The National Book Depot.

13

• THANKS TO ALL ------