Atrioventricular Blocks - Adult Nursing Care I

A condition where there is partial or complete interruption of impulse transmission from the atria to the ventricles.

Atrioventricular (AV) block

Atrioventricular blocks happen when the ___________ node is not functioning correctly or the communication between the AV node and Bundle of His is blocked.

The AV node

What is the rhythm regular or irregular in first degree AV block?

Regular

What is the PR interval in first degree AV block?

The PR interval is prolonged (>20 seconds) BUT CONSTANT

What 2 things set first degree AV blocks apart from other rhythms?

1. Rhythm regular

2. The PR interval is prolonged (>20 seconds) BUT CONSTANT

In a first degree AV block what type of abnormality causes this node to hold the impulse for longer than is normal, causing the PR interval to be

prolonged (>0.20 seconds)?

AV abnormality

True or false first degree AV block may be normal for some

True

All of these factors can cause this type of abnormal rhythm:

- Aging

- Acute MI

- Ischemia or injury to AV node due to MI

- Severe calcification of aortic or mitral

First degree AV block because they all essentially cause the AV node to hold onto the electrical impulse longer than normal, prolonging the PR interval

What type of electrolyte imbalance can cause first degree AV block due to the heart resting too much and thus impairing stimulation (depolarization) of the atria and ventricles.

Hyperkalemia

What type of medications are used to treat first degree AV block?

- Amiodarone (slows down electrical impulses)

- Digoxin

- Beta blockers

- Ca+ channel blockers

What type of abnormal rhythm should be monitored for progression to 2nd or 3rd degree HB?

First degree AV block

This type of abnormal rhythm is common among athletes and most people are asymptomatic

First degree AV block

In second degree AV block type 1 what is the atrial rhythm regular or irregular?

Atrial rhythm regular (P waves plot through on time)

In second degree AV block type 1 what is the ventricular rhythm regular or irregular?

Ventricular rhythm irregular

In second degree AV block type 1 is the atrial or ventricular rate great?

The atrial rate is greater

In second degree AV block type 1 what are the P waves like?

Some P waves are not followed by a QRS complex

In second degree AV block type 1 what is the PR interval like?

The PR interval lengthens with each cycle until a P wave appears without a QRS complex

This type of abnormal rhythm occurs when some, but not all, atrial impulses are blocked from reaching the ventricles

Second degree AV block type 1

This type of abnormal rhythm has more P waves than QRS complexes.

Second degree AV block type 1

This type of abnormal rhythm is where the AV node is similarly malfunctioning. This

time, the AV node is holding the impulse received from the SA node for an increasingly prolonged duration, until eventually it drops the impulse entirely for one beat. Then the cycle usually repeats, starting at a normal or nearly-normal PR interval, increasing over the process of one or more depolarizations, then dropping.

When the depolarizations are allowed through, the QRS complex is normal in appearance because the bundle of His and purkinje fibers are functioning normally.

Second degree AV block type 1

What 3 things set second degree AV block type 1 apart from other rhythms?

1. Ventricular irregular, atrial regular

2. Some P waves are not followed by a QRS complex

3. The PR interval lengthens with each cycle until a P wave appears without a QRS complex

In second degree AV block type 1 & 2 and third degree AV block you would want to monitor this vital sign because their cardiac output is decreased and as a result causes poor blood circulation

Monitor O2

In second degree AV block type 1 & 2 and third degree AV block since you need to monitor their O2 if their level goes too low you may need to apply?

Oxygen if indicated

All of these are ways to treat these 2 types of abnormal rhythms:

- Establish IV access

- Obtain ECG

- Monitor for increasing AV block

- Check medications

Second degree AV block type 1 & 2 and third degree block

If a patient who has second degree AV block type 1 & 2 their heart rate is low what medication should be given to increase it?

Atropine

In second degree AV block type 1 & 2 a treatment option is to do a procedure that uses a catheter to deliver an electric shock to the heart to restore a normal heart rate. What is this called?

External or transvenous pacing

If a patient who has second degree AV block type 1 & 2 and third degree AV block and their BP is low what medication should be given to increase it?

Vasopressors

In second degree AV block type 2 is the atrial rhythm regular or irregular?

The atrial rhythm is regular

In second degree AV block type 2 is the ventricular rhythm regular or irregular?

The ventricular rhythm is irregular

In second degree AV block type 2 is the atrial or ventricular rate greater?

The atrial rate is greater

In second degree AV block type 2 what are the P waves like?

Some P waves are not followed by a QRS complex (sometimes the P waves may be hidden within the T wave)

In second degree AV block type 2 what is the PR interval like?

The PR interval is within normal limits or prolonged BUT CONSTANT

Type of AV block in which the AV node does not CONSISTENTLY allow the electrical impulse from the SA node through

Second degree AV block type 2

What's the main difference between second degree AV block type 1 and type 2?

Type 1's PR interval gets lengthens with each cycle and type 2's PR interval stays constant

What 3 things set second degree AV block type 2 apart from other rhythms?

1. Ventricular irregular, atrial regular

2. Some P waves are not followed by a QRS complex (sometimes the P waves may be hidden within the T wave)

3. The PR interval is within normal limits or prolonged BUT CONSTANT

In third degree AV block is the atrial rhythm regular or irregular?

The atrial rhythm is regular

In third degree AV block is the ventricular rhythm regular or irregular?

The ventricular rhythm is regular

In third degree AV block the ventricular rate is determined by the origin of the _______________?

Escape pacemaker

In third degree AV block what are the P waves like?

Some P waves are not followed by a QRS complex, there are more P waves than QRS complexes (note the P waves do sometimes get "lost" in QRS complexes)

In third degree AV block what is the PR interval like?

There is NO PR interval because the atria and ventricles beat independently of each other

What type of AV block has this? The P waves all march out, QRS complexes all march out; no association between rhythm of P waves and QRS complexes.

Third degree AV block

What type of AV block is this? The SA node is usually functioning normally with this. The AV node, which normally functions as the gatekeeper between the atria and the

ventricles, is NOT transmitting any electricity between the two. As a result, the ventricles are not stimulated to depolarize. The ventricles become irritable, and one or more areas of the ventricles will start to depolarize and take over as the pacemaker for the ventricles.

Third degree AV block

What 4 things set third degree AV block apart from other rhythms?

1. Ventricular rhythm regular, atrial rhythm regular (P waves plot through)

2. The ventricular rate is determined by the origin of the escape pacemaker

3. Some P waves are not followed by a QRS complex, there are more P waves than QRS complexes (note the P waves do sometimes get "lost" in QRS complexes)

4. There is NO PR interval because the atria and ventricles beat independently of each other

What is the main treatment option for third degree AV block?

Temporary pacing (a procedure that uses electrical stimulation to treat an irregular heart rhythm) or permanent pacing (a treatment that involves implanting a battery-powered device in the chest to regulate the heart's electrical activity)

Note client can go into asystole (heart stops) with little or no warning