Cardiac Dysrhythmias Lecture

Overview

• Focus on basic facts about dysrhythmias and their treatment.
• EKG interpretation is covered in a separate resource.
• A quiz will be provided at the end to test key facts.

Sinus Dysrhythmias

Sinus Tachycardia

• Definition: Regular cardiac rhythm, heart rate > 100 bpm.
• Causes: Physical activity, anxiety, fever, pain, anemia, decreased BP or cardiac output.
• Treatment: Address underlying cause (e.g., manage pain).

Sinus Bradycardia

• Definition: Regular cardiac rhythm, heart rate < 60 bpm.
• Causes: Excess vagal stimulation, cardiovascular disease, hypoxia, certain medications.
• Athletic Consideration: Often normal in athletes (e.g., resting HR around 50 bpm).
• Treatment: If symptomatic (e.g., SOB, fatigue), use atropine or pacemaker; no treatment needed if asymptomatic.

Sinus Arrhythmia

• Definition: Normal variant where HR increases with inspiration and decreases with expiration.
• Common In: Children; usually resolves with age.
• Treatment: None needed.

Atrial Dysrhythmias

Atrial Fibrillation (AFib)

• Definition: Rapid, disorganized atrial depolarization leading to quivering.
• Risk: Increased risk of blood clots.
• Interventions: Anticoagulants, cardioversion, antiarrhythmics.
• EKG: Irregular bumps between QRS complexes.

Atrial Flutter

• Definition: Abnormal electrical circuit causing rapid atrial depolarization (250-350/min).
• EKG: Sawtooth F waves.
• Treatment: Antiarrhythmics, cardioversion.

Ventricular Dysrhythmias

Ventricular Tachycardia (V-tach)

• Definition: Rapid ventricular rhythm, > 100 bpm, wide QRS, no P waves.
• Cause: Ischemic heart disease.
• Treatment:
  • With pulse: Cardioversion, antiarrhythmics, address electrolyte imbalances.
  • Without pulse: Defibrillation.
• Progression: Can lead to V-fib.

Ventricular Fibrillation (V-fib)

• Definition: Rapid, ineffective ventricular quivering.
• EKG: No distinct P waves or QRS complexes.
• Treatment: Defibrillation ("D-fib, V-fib").

Asystole

• Definition: Absence of ventricular rhythm.
• EKG: Flat line.
• Treatment: CPR.
• Note: Defibrillation is ineffective.

AV Blocks (Atrioventricular Blocks)

First-degree AV Block

• Definition: Prolonged conduction time (long PR interval).
• Treatment: None typically required.

Second-degree Type 1 AV Block

• Definition: Progressive increase in conduction time until one impulse is blocked.
• EKG: Gradually lengthening PR interval until QRS drop.
• Treatment: Usually not needed.

Second-degree Type 2 AV Block

• Definition: Sudden impulse failure with consistent PR interval.
• EKG: Consistent PR interval with unexpected QRS drop.
• Treatment: Often requires pacemaker.

Third-degree AV Block

• Definition: Complete atrial-ventricular conduction failure.
• EKG: No association between P waves and QRS complexes.
• Treatment: Pacemaker required.

Quiz

1. Dysrhythmia associated with increased clot risk: Atrial Fibrillation.
2. Treatment for V-tach without pulse: Defibrillation.
3. Treatment for V-fib: Defibrillation.

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