ArrhythmiaArrhythmiaprebared by prebared by

Waleed SammodyWaleed SammodyMohammad MansourMohammad Mansour

Supervised bySupervised by Jehad Bani AodihJehad Bani Aodih

Basic FactsBasic FactsAn arrhythmia is an An arrhythmia is an abnormality or abnormality or disturbance in the rate disturbance in the rate or rhythm of the or rhythm of the heartbeat. heartbeat.

Arrhythmias are caused byArrhythmias are caused by

problems with the heart's electrical problems with the heart's electrical system, such as abnormal formation system, such as abnormal formation of the electrical impulses that begin of the electrical impulses that begin heartbeats or by a disruption of the heartbeats or by a disruption of the pattern of conduction of those pattern of conduction of those impulses.impulses.

Because the ventricles are Because the ventricles are primarily responsible for primarily responsible for moving blood through the moving blood through the body, ventricular body, ventricular arrhythmias are often arrhythmias are often more serious than other more serious than other arrhythmias. arrhythmias.

• CAUSES AND RISK FACTORSCAUSES AND RISK FACTORSCauses of ventricular arrhythmias Causes of ventricular arrhythmias include:include: 1- 1- Abnormal electrolyte (mineral, such as Abnormal electrolyte (mineral, such as potassium and magnesium) levels in the blood potassium and magnesium) levels in the blood

2- 2- ElectrocutionElectrocution

3-3- Heart attack (myocardial Heart attack (myocardial infarction)infarction)

4-4- Unstable angina (chest pain).Unstable angina (chest pain).

5-5- Scarring resulting from a heart attackScarring resulting from a heart attack

Ventricular arrhythmias includeVentricular arrhythmias include

Premature ventricular Premature ventricular complexes (PVCs), which complexes (PVCs), which are premature heartbeats; are premature heartbeats; Ventricular tachycardia, an Ventricular tachycardia, an abnormally fast heartbeat; abnormally fast heartbeat; and and Ventricular fibrillation, in Ventricular fibrillation, in which the heart quivers which the heart quivers rather than contracts. rather than contracts.

An electrocardiogram of an episode of sustained ventricular tachycardia.

Premature ventricular Premature ventricular contraction (PVC):contraction (PVC):

  The ventricles fire an early   The ventricles fire an early impulse which causes the impulse which causes the

heart to beat earlier causing heart to beat earlier causing irregularity in the heart irregularity in the heart

rhythmrhythm..

Premature ventricular Premature ventricular contractioncontraction

(PVC)(PVC)

Ventricular TachycardiaVentricular Tachycardia

This is a dangerous type of rapid heart rhythm This is a dangerous type of rapid heart rhythm because it is usually associated with poor because it is usually associated with poor cardiac output (amount of blood ejected out of cardiac output (amount of blood ejected out of the heart)the heart)

It results from abnormal tissues in the ventricles It results from abnormal tissues in the ventricles generating a rapid and irregular heart rhythm.generating a rapid and irregular heart rhythm.

Ventricular Tachycardia

  Rate Rhythm

Ventricular > 100 bpm Regular

Atrial None  

P-Wave Absent  

     

P-R Interval Absent  

QRS Complex> .10 seconds

 

Both ventricular tachycardia and ventricularBoth ventricular tachycardia and ventricularfibrillation are considered lethal arrhythmiasfibrillation are considered lethal arrhythmias

Only ventricular fibrillation, is linked to the Only ventricular fibrillation, is linked to the clinical term “sudden death.” This rhythm is clinical term “sudden death.” This rhythm is

not able to support life and will lead to not able to support life and will lead to clinical death if untreatedclinical death if untreated

Ventricular fibrillationAll output from the heart stops, blood

pressure falls rapidly, and the patient loses consciousness .

During ventricular fibrillation theDuring ventricular fibrillation the heart is electrically stimulated heart is electrically stimulated by multiple ectopic sites so that by multiple ectopic sites so that instead of contractinginstead of contracting rhythmically in one united wave rhythmically in one united wave of depolarization, the muscleof depolarization, the muscle actually fibrillates actually fibrillates

WHAT ARE THE SYMPTOMS?WHAT ARE THE SYMPTOMS?Diminished or irregular Diminished or irregular pulse;pulse;

Fatigue;Fatigue;

Shortness of breath;Shortness of breath;

Fainting (syncope); Fainting (syncope);

Palpitations (awareness Palpitations (awareness of one's own heartbeat);of one's own heartbeat);

Low blood pressureLow blood pressure;;

Chest pain; andChest pain; and

Cardiac arrest.Cardiac arrest.

Ventricular fibrillationVentricular fibrillation

An electrocardiogram reflecting the irregular, pulseless electrical activity of ventricular fibrillation

TREATMENT APPROACHTREATMENT APPROACH

●Many cases of arrhythmias may not Many cases of arrhythmias may not require treatment. Other arrhythmias require treatment. Other arrhythmias can be treated by treating any can be treated by treating any underlying heart disease. Treatments underlying heart disease. Treatments for ventricular arrhythmia includesfor ventricular arrhythmia includes

•DefibrillationDefibrillationMedication (beta-blockers Medication (beta-blockers and antiarrhythmic agents); and antiarrhythmic agents); Radiofrequency catheter Radiofrequency catheter ablation; ablation; Angioplasty; and Angioplasty; and Pacemaker implantation. Pacemaker implantation.

Heart block, also called Heart block, also called atrioventricular block or A-V block, is atrioventricular block or A-V block, is an abnormality of the spread or flow an abnormality of the spread or flow of electrical activity from the upper of electrical activity from the upper heart chambers, the atria, to the heart chambers, the atria, to the lower chambers of the heart, the lower chambers of the heart, the ventricles. ventricles.

Atrioventricular block (AVB):  the sinus Atrioventricular block (AVB):  the sinus node may be generating heart beats node may be generating heart beats

causing the atria to contract at a normal causing the atria to contract at a normal rate, however not every electrical rate, however not every electrical

impulse coming from the atria is being impulse coming from the atria is being passed down to the ventricles by the passed down to the ventricles by the atrioventricular node due to a block in atrioventricular node due to a block in

conduction.  There are various types of conduction.  There are various types of AV block depending upon the AV block depending upon the

mechanism of block.mechanism of block.

Classify heart block based on the length the

delay

First-degree heart blockFirst-degree heart block

Heart beat impulses are delayed in the Heart beat impulses are delayed in the A-V node, but ultimately reach the A-V node, but ultimately reach the ventricles. Sometimes, first-degree ventricles. Sometimes, first-degree heart block can eventually lead to other heart block can eventually lead to other forms of heart block. forms of heart block.

.

In first-degree heart block, the In first-degree heart block, the ECG shows one QRS wave for ECG shows one QRS wave for every P wave, but the pause is every P wave, but the pause is

greater than normalgreater than normal

Second-degree heart blockSecond-degree heart block

Heart beat impulses are delayed or blocked in Heart beat impulses are delayed or blocked in or around the A-V node, and some of the or around the A-V node, and some of the impulses fail to reach the ventricles; Second-impulses fail to reach the ventricles; Second-degree heart block is further divided into two degree heart block is further divided into two sub-types: sub-types:

Type I second-degree heart blockType I second-degree heart block, also called , also called Mobitz Type I heart block or the Wenckebach Mobitz Type I heart block or the Wenckebach phenomenon. phenomenon. Type II second-degree heart blockType II second-degree heart block, also called , also called Mobitz Type II blockMobitz Type II block . .

second degree block referred to as second degree block referred to as Mobitz I or WenckebachMobitz I or Wenckebach

Occasionally sinus impulses will pass Occasionally sinus impulses will pass through the AV node at slower and through the AV node at slower and slower rates until excitation is actually slower rates until excitation is actually blockedblocked After that the cycle of delay-delay-After that the cycle of delay-delay-block repeats itselfblock repeats itself

This phenomenon is a form of second This phenomenon is a form of second degree block referred to as Mobitz I or degree block referred to as Mobitz I or Wenckebach.Wenckebach.

Second-Degree Heart Block: Mobitz I

Mobitz II is another form of second-Mobitz II is another form of second-degree blockdegree block

Mobitz II occurs within the context of a basic Mobitz II occurs within the context of a basic rhythm when a P wave occurs but is not rhythm when a P wave occurs but is not followed by a QRS. This is a more serious form followed by a QRS. This is a more serious form of second-degree block as it occurs without of second-degree block as it occurs without warningwarning

The basic rhythm would be regular except The basic rhythm would be regular except for the periods of the block. These occur most for the periods of the block. These occur most often because there is block below the bundle often because there is block below the bundle of Hisof His

The P to P interval is once again regular. The P to P interval is once again regular. The QRS response, because of the The QRS response, because of the ““dropped beat,dropped beat,”” will appear irregular will appear irregular

In second-degree type II block, In second-degree type II block, notice that the P wave (4th bump) notice that the P wave (4th bump) isn't followed by the QRS wave, isn't followed by the QRS wave, because the ventricles weren't because the ventricles weren't

activated. activated.

Third-degree heart blockThird-degree heart blockAlso called complete heart block, each Also called complete heart block, each sinus node impulse is completely sinus node impulse is completely interrupted in the A-V node or beyond, interrupted in the A-V node or beyond, and the ventricles must generate their and the ventricles must generate their own impulse to contract. Depending on own impulse to contract. Depending on its cause, third-degree block may be its cause, third-degree block may be transient (temporary) or permanent.transient (temporary) or permanent.

When no impulses from the atria excite the When no impulses from the atria excite the ventricle, a situation of complete block existsventricle, a situation of complete block exists

Clearly this is the most serious form of heart Clearly this is the most serious form of heart block as the ventricles are now left on their block as the ventricles are now left on their own to beatown to beat

Because they are capable of self-Because they are capable of self-automaticity, a ventricular rhythm is presentautomaticity, a ventricular rhythm is present

However, at a rate inherent to the However, at a rate inherent to the ventricles the patientventricles the patient’’s rhythm will s rhythm will significantly slowsignificantly slow

In addition, the effect of In addition, the effect of atrial kick is lostatrial kick is lost

Third-degree heart blockThird-degree heart block