Podcast Beta
Questions and Answers
What is the most common cause of atrioventricular (AV) block?
Which of the following statements best describes First Degree AV Block?
Which characteristic differentiates Mobitz type I from Mobitz type II Second Degree AV Block?
What does third-degree AV block signify?
Signup and view all the answers
In Mobitz type II Second Degree AV Block, how does the PR interval behave?
Signup and view all the answers
What is a characteristic finding in Mobitz type I AV Block regarding QRS complexes?
Signup and view all the answers
What is the typical heart rate observed in First Degree AV Block?
Signup and view all the answers
Which of the following medications is NOT commonly associated with AV block?
Signup and view all the answers
Study Notes
Atrioventricular (AV) Block
- AV block is an interruption of electrical impulses traveling from atria to ventricles
Causes of AV Block
- Idiopathic fibrosis & sclerosis of conduction system (50% of patients)
- Ischemic heart disease (40%)
- Medications (beta-blockers, calcium channel blockers, digoxin, amiodarone)
- Increased vagal tone
- Valvulopathy
- Congenital heart disease, genetic, or other disorders
First Degree AV Block
- All normal "P" waves are followed by "QRS" complexes
- PR interval is longer than normal, greater than 0.20 seconds
- Rate: 60 bpm
- Rhythm: Regular
- P wave: Normal
- PR interval: 0.32 sec
- QRS: 0.08 sec
Second Degree AV Block
- Some "P" waves are followed by "QRS" complexes, while others are not
- Divided into Mobitz Type I and Mobitz Type II
Mobitz Type I
- PR interval progressively lengthens with each beat until atrial impulse is not conducted and "QRS" complex is dropped
- Also called Wenckebach phenomenon
- AV nodal conduction resumes with the next beat, and the sequence repeats
- Rate: 60 bpm
- Rhythm: Regularly irregular
- P wave: Present, 1-2 before "QRS"
- PR interval: 0.2-0.36 sec (progressively lengthens)
- QRS: 0.08 sec, skipped every after 3 beats
Mobitz Type II
- PR interval is constant
- Beats are intermittently nonconducted and "QRS" complexes dropped, usually in a repeating cycle of every 3rd (3:1 block) or 4th (4:1 block) "P" wave
- Rate: 60 bpm
- Rhythm: Regularly irregular
- P wave: Normal, present
- PR interval: 0.12 sec
- QRS: 0.08 sec, skipped every after 3 beats
Third-Degree AV Block
- Complete heart block with no electrical communication between atria and ventricles
- No relationship between "P" waves and "QRS" complexes (AV dissociation)
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the concept of Atrioventricular (AV) block, including its causes, types, and characteristics. You will explore First Degree and Second Degree AV blocks, along with their specific features such as PR intervals and rhythms. Test your knowledge on this essential topic in cardiology!
