ECGJUNCTIONAL & VENTRICULAR

ARRHYTHMIAS

MARYAM JAMILAH BINTI ABDUL HAMID082013100002IMS BANGALORE

INTRODUCTION

Student should be able to understand what is junctional and ventricular arrhythmias

Students should be able to identify these two arrhythmias through electrocardiograph

Student should know the classification that comes below these two arrhythmias

CLASSIFICATIONS

JUNCTIONAL ARRHYTHMIA

VENTRICULARARRHYTHMIA

Junctional Rhythm

AV Nodal Reentrant Tachycardia

Ventricular fibrillation

Ventricular tachycardia

Premature Ventricular Contraction

JUNCTIONAL ARRHYTHMIAAV Nodal Reentrant Tachycardia

-A type of supraventricular tachycardia (SVT); above thebundle of His-Reentry circuit forms within or just next to the AV node-Slow pathway is located inferior and slightly posterior to

theAV node, often following the anterior margin of the coronarysinus.-The fast pathway is usually located just superior andposterior to the AV node

-common AVNRT; anterograde conduction is via the

slow pathway and the retrograde conduction is via

the fast pathway

-uncommon AVNRT; anterograde conduction is via

the fast pathway and the retrograde conduction is

via the slow pathway

ECG- P wave that falls after the QRS complex

Junctional Rhythm-Abnormal heart rhythm resulting from impulses

coming from a locus of tissue in the area of

the AV node

-AV node as the pacemaker

-Retrograde conduction

ECG

- Without a P wave or with an inverted P wave. 

- Retrograde P waves refers to the depolarization from the AV node back towards the SA node

VENTRICULAR ARRHYTHMIACause:1. Sudden electrical shock of the heart 2. Ischemia of the heart muscle, of its

specialized conducting system3. Both

Normal person:After electrical impulses reach the

ventricles, they dieoff Because all the ventricular muscle is in

refractory phase

Types of Ventricular Arrhythmias

Premature Ventricular Contraction Ventricular Tachycardia

Up to 200 bpm Ventricular Flutter

200-350 bpm Ventricular Fibrillation

350-500 bpm

Premature Ventricular Contraction

Heartbeat is initiated by Purkinje fibres

in the ventricles rather than by the SA

node

Ventricles contract first and before the

atria have optimally filled the ventricles

with blood, which means that circulation

is inefficient

ECG

Ventricular Tachycardia

Ventricular Flutter

Ventricular Fibrillation

-ventricular QRS complexes are highly polymorphic analogous to the ventricular extra systoles

-Retrograde conduction to the atria is almost always blocked; thus, undisturbed atrial activity is scattered with P waves without any relation to QRS complexes.

-ECG shows large

oscillation; main

and terminal

deflections can no

longer be

differentiated

ECG-fast-small potential fluctuations in rate-rhythm-amplitude-appearance

*a fatal condition

CIRCUS MOVEMENTS AS THE BASIS FOR VENTRICULAR FIBRILLATION

Define circus movements:‘Re-entry’ of the impulse into muscle that has already been excited

Why? Pathway around the circle is too long; dilated heart Velocity of conduction becomes decreased; blockage of Purkinje

system, ischemia of the muscle or high blood potassium levels Refractory period of the muscle might become greatly

shortened; drugs (epinephrine) or after repetitive electrical stimulation

CONCLUSION

Junctional arrhythmia; AV nodal reentrant tachycardia Junctional Rhythm

Ventricular arrhythmia; Premature Ventricular Contraction Ventricular Tachycardia Ventricular Flutter Ventricular Fibrillation

REFERENCES1. AK JAIN Medical Physiology, 3rd edition2. Davidson's Principles and Practice of Medicine, 21st Edition3. http://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia4. http://en.wikipedia.org/wiki/Premature_ventricular_contraction5. American Heart Association. (2012, September 05).Ventricular

fibrillation. Retrieved from http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Ventricular-Fibrillation_UCM_324063_Article.jsp

6. Mayo Clinic Staff. (2011, November 01). Diseases and conditions ventricular fibrillation. Retrieved from http://www.mayoclinic.org/diseases-conditions/ventricular-fibrillation/basics/definition/CON-20034473

7. American Heart Association. (n.d.). Arrhythmias (ventricular fibrillation). Retrieved from http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt

8. http://www.drsegal.com/medstud/ecg/junction.htm9. http://en.wikipedia.org/wiki/Junctional_rhythm