NCLEX - AV Node Block, Sick Sinus Syndrome, & Bundle Branch Block

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Here are key facts for NCLEX from the AV Node Block, Sick Sinus Syndrome, & Bundle Branch Block tutorial, as well as points of interest at the end of this document that are not directly addressed in this tutorial but should help you prepare for the boards. See the tutorial notes for further details and relevant links.

VITAL FOR NCLEX

First-Degree AV Block

1. Assessment findings: Long PR interval on ECG (> 200 milliseconds); patient is typically asymptomatic. 2. Nursing implications: Usually no treatment required, but monitor for changes in cardiac rhythm. 3. Patient education: Teach patient about possible medication effects (channel blockers or digoxin). 4. Risk factor identification: Be aware of myocarditis, hypokalemia, hypomagnesium as potential causes.

Second-Degree AV Block

1. Assessment differentiation:

Mobitz Type 1: Recognize progressively longer PR intervals until ventricular contraction is skipped.
Mobitz Type 2: Identify consistent PR intervals with unexpected skipped ventricular depolarization.

2. Symptom assessment:

Type 1: Monitor for dizziness, fainting.
Type 2: Assess for chest pain, difficulty breathing, tiring easily, hypotension.

3. Nursing interventions:

Type 1: Monitor asymptomatic patients; review medications as potential causes.
Type 2: Prepare patient for pacemaker implantation; provide pre/post-procedure education.

Third-Degree AV Block

1. Critical assessment finding: AV dissociation with no relationship between P waves and QRS complexes. 2. Patient monitoring: Assess for fatigue/lethargy, dizziness, fainting, slow heart beat. 3. Priority intervention: Prepare for pacemaker implantation; monitor for signs of low cardiac output. 4. Risk factor identification: Recognize both congenital (maternal autoimmune conditions) and acquired causes (surgery complications, infections, medications).

HIGH YIELD

First-Degree AV Block

1. Special populations: Recognize as common in highly-trained athletes due to enlarged heart muscle. 2. Complication monitoring: Assess for increased risk of atrial fibrillation.

Second-Degree AV Block

1. Clinical significance:

Understand that Type 1 may be physiologic in healthy athletes.
Recognize that Type 2 is pathologic and requires intervention.

2. Etiology awareness:

Consider cardiac injury (fibrosis, sclerosis, scarring from heart attack).
Assess for history of Lyme disease (particularly Type 2).
Review medications: beta blockers, calcium channel blockers, digoxin, amiodarone.

3. Complication prevention: Monitor Type 2 for progression to complete heart block.

Third-Degree AV Block

1. Pathophysiologic understanding: Low cardiac output deprives organs of oxygen. 2. Medication review: Identify potentially causative medications (digoxin, calcium-channel blockers, beta blockers, tricyclic antidepressants, clonidine). 3. Health history assessment: Screen for radiotherapy, infection (diphtheria, rheumatic fever), hypertension, cancer.

Sick Sinus Syndrome

1. Key assessment findings: Episodes of bradycardia, sinus pauses or arrest, and junctional escape beats. 2. Etiology understanding: Caused by damage to the SA node, including age-related degeneration. 3. Patient education: Teach about the need for pacemaker implantation.

Bundle Branch Blocks

1. ECG interpretation:

QRS complex greater than 120 ms in complete bundle branch block.
RBBB: Identify rsR' "bunny ear" pattern in leads V1-V3; slurred S waves in I, aVL, V5 and V6.
LBBB: Recognize broad monophasic R wave and absent Q waves in I, V5, V6; ST and T wave displacement.

2. Clinical correlation:

RBBB may be present in otherwise healthy individuals.
LBBB is indicative of left heart disease requiring further assessment.

Beyond the Tutorial

Below is information not explicitly contained within the tutorial but important for NCLEX.

AV Blocks - Nursing Care

1. Fall prevention: Implementing safety measures for patients with symptomatic bradycardia. 2. Activity tolerance: Assessing and planning appropriate activity levels for patients with conduction disorders. 3. Medication administration: Understanding timing and significance of cardiac medications in patients with conduction disorders.

Sick Sinus Syndrome - Patient Care

1. Pacemaker care: Teaching patients about activity restrictions, electromagnetic interference, and follow-up after implantation. 2. Symptom management: Interventions for fatigue and activity intolerance related to bradycardia. 3. Monitoring parameters: Critical vital signs and symptoms requiring immediate reporting.

Bundle Branch Blocks - Nursing Implications

1. Cardiac monitoring: Interpretation of telemetry findings and appropriate nurse response. 2. Patient education: Explaining the significance of ECG findings and necessary follow-up. 3. Discharge planning: Resources and referrals for patients newly diagnosed with bundle branch blocks.