4.4 Atrial Tachyarrhythmias Flashcards
Which ECG wave corresponds to atrial systole?
The P wave
List and describe the four classifications of atrial fibrillation
Paroxysmal: <1 week
Persistent: >1 week
Long-Standing Persistent: >1 year
Permanent: Attempts to restore are abandoned
List four ways in which cardiac disease can contribute to AF
- Electrical remodeling
- Ca2+ handling abnormalities
- Autonomic nerve remodelling
- Structural remodelling
Where do ectopic beats most commonly occur in AF?
Around the pulmonary veins
AF leads to atrial electrical remodelling. What kind of remodelling takes place?
- Reduced refractory period
- Shorter AP duration
- Uneven AP duration across atria
- Altered ion channel expression/function
Atrial volume and pressure overload results in atrial remodelling. Give some examples of adaptations that can occur during this process.
- Myocyte hypertrophy
- Fibrosis
- Metabolic abnormalities
What three factors increase the likelihood of electrical re-entry in AF patients?
- Slower conduction
- Shortened refractory period
- Anatomical substrate (e.g. fibrosis)
List some symptoms of AF
- Palpitations
- Dyspnoea
- Fatigue
- Syncope/presyncope
- Chest pain
Describe the four aspects of AF treatment, and potential solutions for each
Rate Control: <110bpm (beta blocker, Ca2+ channel blocker)
Rhythm Control: Anti-arrhythmic medication
Anticoagulation: Direct thrombin inhibitors
Risk factor management: weight loss, anti hTn, glucose control, exercise
Describe the three functions of the atria
- Reservoir (filling)
- Conduit (passive emptying)
-Pump (active emptying)
How is atrial fibrillation diagnosed? What device can do this?
- Diagnosed using ECG
- Due to possible transient AF, can be diagnosed with continuous Holter monitor, implamntable recorders, or even Apple watches.
Explain how pulmonary vein isolation works
- Using a catheter to enter the pulmonary veins, and electrically isolate the tissue by burning it.
- This prevents ectopic beats from this area
How does AF beget AF?
- AF causes electrical remodelling
- Makes it more likely for abnormalities in cardiac conduction
- Causes more AF
Why does AF cause palpitations?
The AV node is flooded with irregular signals trying to propagate through into the ventricles, increasing heart rate.
How can AF cause dyspnoea
- Cardiac output decrease
- Elevated left sided heart pressure
- Pulmonary oedema -> SOB
