Heart Block Flashcards
1
Q
First Degree Heart Block PR Interval
A
Longer than 0.2 seconds
2
Q
First Degree Heart Block Causes
A
- Common 7% prevalence
- Increased vagal tone
- AV node blocking drugs (BBs, CCB, digoxin, amiodarone)
- MI
3
Q
First Degree Heart Block Medication Causes
A
Disopyramide, flecainide, propafenone, beta-blockers, CCBs, digoxin, magnesium
4
Q
First Degree Heart Block Management
A
- Does not require investigation or treatment if asymptomatic, particularly in young, healthy people
- Cardiology referral if cardiac symptoms
- Follow up ECGs annually
- Contra-indication to to drugs listed
5
Q
Second Degree Heart Block Mobitz Type I
A
- Progressive prolongation of PR interval following each atrial impulse until impulse fails to be transmitted
- Non conducted P wave can be superimposed on T wave
6
Q
Second Degree Heart Block Mobitz Type II ECG
A
- Intermittent failure of conduction of atrial impulses to ventricles, PR interval is constant
- Can be 2:1 can be 3:1
- Ratio can vary within the trace
- Usually due to impaired conduction so QRS complexes tend to be wider
7
Q
Second Degree Heart Block Mobitz Type Aetiology
A
- If type 1 due to AV nodal disease, usually relatively benign
- If caused by His-Purkinje abnormalities likely to progress to complete heart block
- Causes include
- Age-related fibrosis
- Medication
- Coronary heart disease
- Structural abnormalities
8
Q
Complete Heart Block
A
- Complete failure
- P waves at 75bpm, unrelated to QRS rhythm
- Congenital CHB strongly associated with anti-Ro in SLE
- Can occur at AV node or infra nodally in His-Purkinje system
9
Q
Complete Heart Block Nodal Block
A
- New pacemaker will arise above or in the bundle of His, QRS complexes will be narrow
- Usually fire reliably and a reasonably rapid rate (45-60bpm
- Respond to exercise and atropine
- Remain asymptomatic for good periods of time
- Non- specific symptoms e.g. fatigue, dizziness, reduced exercise tolerance, palpitations
10
Q
Complete Heart Block Below Bundle of His
A
- Usually have subsidiary pacemaker in right or left bundle branches
- Wide QRS usually slow (<45bpm)
- Usually haemodynamicaly compromised and overtly symptomatic
