Questions and Answers
What are junctional rhythms?
Rhythms that are initiated in the area of the AV junction - usually NOT life threatening.
Define retrograde.
Contrary (or opposite) to the normal expected path of movement.
What is the characteristic of the P wave in junctional rhythms?
The P wave may be absent, or after the QRS and inverted.
What is a premature junctional complex (PJC)?
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What is the rate and rhythm characteristic of a premature junctional complex (PJC)?
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Is a non-compensatory pause caused by the SA node being depolarized by the ectopic beat?
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In a compensatory pause, the SA node is affected.
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Which of the following can cause premature junctional contractions (PJCs)?
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What is called when the SA node fails to generate an impulse?
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What is an accelerated junctional rhythm?
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At what rate do junctional tachycardia rhythms exceed?
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Is it true that isolated occurrences of PJCs are not life-threatening?
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The intrinsic firing rate of the AV node is __________ BPM.
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Can myocardial ischemia precipitate PJCs?
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What is a pause that occurs after an ectopic beat called if the SA node is unaffected?
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Are PJCs often life-threatening?
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Study Notes
Junctional Rhythms
- Initiated in the AV junction area, junctional rhythms are typically not life-threatening.
- P wave in junctional rhythms may be absent, appear after the QRS complex, or be inverted due to retrograde movement of impulses.
Premature Junctional Complex (PJC)
- A PJC arises earlier than the next expected complex and can be identified within sinus rhythm by assessing the P wave characteristics.
- Characteristics of PJC: irregular rhythm, inverted or absent P wave, and a PR interval less than 0.12 seconds if the P wave is present.
Junctional Escape Rhythm
- Occurs when the SA node fails or its impulse generation is slower than that of the AV node, which takes over as the pacemaker.
- Often manifests as junctional bradycardia if the rate drops below 40 BPM.
Accelerated Junctional Rhythm
- Results from increased automaticity in the AV junction, leading to a discharge rate of 60-100 BPM.
Junctional Tachycardia
- Defined by a junctional firing rate exceeding 100 BPM, often requiring careful monitoring due to potential underlying issues.
Causes of PJCs and Junctional Rhythms
- Common triggers include fever, anxiety, exercise, electrolyte imbalances, heart failure, and substance use (e.g., caffeine, tobacco).
- Can also result from ischemic heart conditions, certain medications, or may be idiopathic.
Interpretation of Rhythms
- When examining P waves in junctional rhythms, they may be inverted, hidden in the QRS complex, or entirely absent.
- PJCs typically resemble premature atrial contractions (PACs) but are less common than PACs or PVCs.
Symptomatic vs. Asymptomatic
- Patients experiencing symptoms like shortness of breath or chest pain are considered symptomatic, necessitating more urgent interventions.
- Isolated PJCs are generally not life-threatening, making them manageable in most cases.
Distinguishing Features
- Junctional rhythms often exhibit a negative P wave deflection on the isoelectric line, indicating the retrograde nature of the electrical impulse.
- A pause can be classified as noncompensatory when it interrupts the underlying rhythm due to ectopic beats.
Treatment Considerations
- Management of junctional escape rhythms or junctional tachycardia focuses on addressing the underlying cause, particularly if the patient exhibits symptoms.
Key Identifiers in Evaluation
- The intrinsic firing rate of the AV node ranges from 40 to 60 BPM.
- In case of junctional escape beats, SA node disease, hypoxia, and certain cardiac drugs may contribute to the condition's onset.
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Test your knowledge of junctional rhythms and related concepts with these flashcards. This quiz includes key terms and definitions essential for understanding cardiovascular rhythms. Perfect for students studying cardiology or preparing for exams.
