Heart Blocks Flashcards
AV blocks are caused by
A blockage of the AV node
If the Rs are far from P
Then you have a first degree
Longer, Longer, Longer, Drop!
Then you have a Wenckebach
If some Ps don’t get through
Then you have a Mobitz 2
If Rs and Ps don’t agree
Then you have a 3rd degree
1st degree heart blocks are distinguished by
A PR interval of greater than 0.2 seconds
A 2nd degree type I heart block or “Wenckebach” is distinguished by
A PR interval that gets longer until it drops a QRS complex
A 2nd degree type II or Mobitz II is distinguished by
An irregular RR interval that is caused by occasional P waves that don’t generate QRS complexes
A 3rd degree heart block is distinguished by
A constant RR interval that Occurs indecently of Constant P waves
A high-grade 2nd degree heart block has
2 or more consecutive dropped beats
An un-typable heart block is
A 2nd degree with a 2:1 conduction rate
1st degree etiology
- Sympatholytics (beta blockers, Ca2+Channel Blockers)
- Parasympathomimetics
- Increased Vagal Tone
- Hyperkalemia-Hyperkalemia
- Rheumatic Fever-Myocarditis
- Aging (degeneration of conduction pathways)
- Digitalis-Idiopathic
- Inferior MI (Right Coronary Artery feeds inferior wall AND supplies AV node)
2nd degree type I etiology
- Sympatholytics (beta blockers, Ca2+Channel Blockers)
- Parasympathomemetics-Increased Vagal Tone
- Hyperkalemia
- Hyperkalemia
- Rheumatic Fever
- Myocarditis
- Aging (degeneration of conduction pathways)
- Digitalis-Idiopathic
- Inferior MI (Right Coronary Artery feeds inferior wall AND supplies AV node)
Etiology of 2nd degree type II heart blocks
- Sympatholytics (beta blockers, Ca2+Channel Blockers)
- Parasympathomemetics-Increased Vagal Tone
- Hyperkalemia
- Hyperkalemia
- Rheumatic Fever
- Myocarditis
- Aging (degeneration of conduction pathways)
- Digitalis-Idiopathic
- Inferior MI (Right Coronary Artery feeds inferior wall AND supplies AV node)
3rd degree heart block etiology
- Increased vagal tone: carotid sinus massage, pain, sleep,
etc. - Surgery and trauma to the heart 5. Surgery and trauma to the heart
- Cardiomyopathies
- Myocarditis
- Infective endocarditis
- Electrolyte disorders
- Congenital heart disease