Atrioventricular block Flashcards
What is atrioventricular block?
Interrupted or delayed conduction between the atria and the ventricles
What are the types of AV block?
First degree
Second degree (Mobitz type 1 and type 2)
Third degree
What are the causes of AV block?
Idiopathic fibrosis of the conduction system
Ischemic heart disease
Cardiomyopathy (e.g., due to amyloidosis or sarcoidosis)
Infections (e.g., Lyme disease, bacterial endocarditis)
What is first degree heart block?
PR interval > 200 ms
No interruption in atrial to ventricular conduction
Rate of SA node = heart rate
What are the clinical features and diagnosis of first degree heart block?
Asymptomatic
Incidental ECG
What is the treatment of first degree heart block?
No treatment
What are the clinical features and diagnosis of second degree heart block?
(Mobitz type I) Progressive lengthening of the PR interval until a beat is dropped, Rate of SA node > heart rate, Usually asymptomatic
(Mobitz type 2) Single or intermittent non-conducted P waves without QRS complexes, without progressive lengthening, symptoms (Fatigue, Dyspnea, Chest pain, Dizziness, syncope)
(ECG)
What are the treatments for second degree heart block?
(Hemodynamically stable) Monitoring
Hemodynamically unstable) Atropine (increases heart rate
What is third degree heart block?
Third-degree AV block is a complete block with no conduction between the atria and ventricles
What are the clinical features and diagnosis of third degree heart block?
(ECG)P waves and QRS complexes have their own regular rhythm but bear no relationship to each other (Clinical featuers) Nausea, dizziness Stokes-Adams attacks Cardiac arrest Other symptoms mentioned previously
What is the treatment for third degree heart block?
Permanent pace maker
Low blood pressure → dopamine
Heart failure → dobutamine
