Flashcards in Heart Block Deck (14):
1
How long is a normal QRS in seconds?
0.06-0.12 seconds
2
How long can a normal QT interval be?
0.44 seconds
3
What normally causes a heart block?
Abnormal conductance of the action potential at the AVN
4
What is a first degree heart block?
An extended PR interval of over 0.20, requires no treatment
5
Second degree mobitz type 1 heart block is?
Progressive prolongation of the PR interval culminating in a non-conducted P wave. Doesn't usually require any intervention either
6
Second degree mobitz type 2 heart block is?
Constant PR interval with intermittently non-conducted P waves and is caused by a conduction disorder in the bundle of Hiss. Always SINISTER and requires pacemaker
7
Third degree heart block is?
Complete AV node dissociation causing a ventricular escape rhythm at around 30BPM. Results in narrow QRS if from the bundle of Hiss and broad if it's originating in the ventricles. Requires pacemaker
8
What are bundle branch blocks
Abnormal conduction patterns causing the QRS to become longer than 0.12 as bundles conduct slowly and late
9
What does it mean for those reading the ECG of someone with a LBBB?
No interpretations can be made about the ST segment or T wave
10
Signs of RBBB
QRS >0.12 seconds and secondary R wave and slurred S wave. Results in M appearance in V1-3 and W appearance in V6
11
Signs of LBBB?
QRS >0.12 seconds M pattern in V5 and inverted T waves in leads I, aVL, V5-V6
12
Causes of RBBB
PE and pulmonary heart disease
13
Causes of LBBB
IHD, cardiomyopathy, idiopathic fibrosis
14