Junctional Rhythms
This rhythm serves as a backup safety mechanism when the SA node fails, firing at its intrinsic rate of 40 to 60 beats per minute to prevent cardiac standstill
What is a Junctional Escape Rhythm?
Rather than a true block, this is a delay in the transmission of the electrical impulse at the AV node, detected by a PR interval longer than 0.20 seconds
What is a 1st Degree AV Block?
In a junctional rhythm, this waveform is often inverted in lead II due to the retrograde depolarization of the atria.
What is a P wave?
This condition, defined as a lack of adequate oxygen and blood flow to the AV junction, is the primary underlying cause of an accelerated junctional rhythm.
What is Ischemia? (Page 1109)
If a patient with a heart block or junctional rhythm is asymptomatic and has normal vital signs without signs of poor perfusion, this is the only treatment required in the field
What is observation?
It is a junctional rhythm with a heart rate of less than 40 beats per minute, which can significantly compromise cardiac output.
What is Junctional Bradycardia?
This more serious intermittent block drops beats without progressively lengthening the PR interval, and the PR interval remains constant for all conducted beats.
What is a Second Degree AV block Type 2?
If a P wave appears before the QRS complex in a junctional rhythm, the PR interval will consistently be less than this duration.
What is 0.12 Seconds or 120ms
The use of these three common lifestyle substances is a frequent etiology for premature junctional contractions (PJCs)
What are caffeine, tobacco, and alcohol?
For patients with symptomatic bradycardia (like a slow junctional rhythm), this parasympatholytic medication is given rapidly via IV push at a starting dose of 1 mg
What is atropine?
These early beats originate in the AV junction and can be triggered by lifestyle factors such as the use of caffeine, tobacco, or alcohol.
What are PJCs? (Premature Junctional Complex)
Also known as a Wenckebach block, this intermittent block produces a cyclic pattern where the PR interval becomes progressively longer until a QRS complex is completely dropped.
What is a Second Degree Type 1?
This three word title describes an early, extra heart beat that originates in the AV junction.
What is a premature junctional complex?
Medication toxicity is a frequent underlying cause for both AV blocks and PJCs; this is especially true for this specific medication prescribed for heart failure
What is digitalis (or Lanoxin)?
If Atropine is ineffective, contraindicated, or the patient has impending hemodynamic collapse, paramedics should immediately initiate this electrical therapy starting at a rate of 60 BPM
What is transcutaneous cardiac pacing (TCP)?
When the AV junction's automaticity increases enough to produce a rate exceeding 100 beats per minute, it is classified as this rhythm.
What is Junctional Tachycardia?
In this severe block, there is a total absence of conduction between the atria and the ventricles, causing them to pace the heart entirely independently of each other.
What is a 3rd Degree AV Block?
In a complete (third-degree) heart block, the atrial rate remains unaffected, but the ventricular rate is usually between this range if the escape pacemaker is located in the AV junction.
What is 40-60 (Page 1105)
In addition to increased vagal tone or a heart block, a junctional bradycardia can be caused by intrinsic disease of this specific cardiac structure
What is the AV node? pg 1108
If a symptomatic bradycardic patient does not respond to Atropine, medical control may order this inopressor drip, typically starting at an initial adult dose of 8 mcg/min
What is norepinephrine?
This rhythm has a rate between 60 and 100 beats per minute and occurs when the AV junction discharges faster than its intrinsic rate due to increased automaticity.
What is Accelerated Junctional?
This specific block is characterized by a set ratio where there are exactly two P waves for every one QRS complex.
What is a 2:1 AV block?
Because a premature junctional contraction (PJC) depolarizes the SA node and interrupts the heart's normal cadence, the pause that follows it is usually this type of pause.
What is a noncompensatory pause? (Page 1107)
zErhis condition—defined as a lack of adequate oxygen in the body or tissues—is a recognized clinical cause of premature junctional contractions
What is hypoxia? pg 1107
According to the drug protocols, Atropine is contraindicated and should not be given to patients suffering from these two specific high-grade AV blocks if they present with a wide QRS complex
What are Second-degree Mobitz Type II and Third-degree AV blocks?