Atrial Arrhythmia Flashcards
What are the two main types of atrial arrhythmias?
- Atrial fibrilation
- Atrial flutter
What are some characteristics associated with atrial fibrillation?
Electrical impulses triggered from multiple locations in atria
Electrical activity is chaotic rather than organized
Atrial walls, quiver rather than contract
EF is reduced due to loss of atrial kick (significant for patients with medium and reduced EF)
What are some characteristics of atrial flutter?
Electrical activities in atria is coordinated
Atria do contract but at a very rapid rate (250-350 contractions per minute, only 1/2 get across to the AV node)
Which of the two atrial arrhythmias is most common?
Atrial fibrillation is more common compared to atrial flutter
Is atrial fibrillation on its own life-threatening?
No, but it is associated with significant impairment of life and increases of stroke and LVH (due to loss of atrial kick)
What is atrial kick?
This phenomenon relies on the Frank-Starling Laws. In Afib, the atria no longer pump an extra amount of blood into the ventricles during diastole. This results in less stretching of the ventricles, which in turn causes less forceful ejection of blood during systole
What happens to the ECG reading of a patient with atrial fibrillation?
Each cycle of ECG waves lasts a different duration
They are the same duration in healthy patients
How common is atrial fibrillation?
Fairly rare in in patients under 60 (0.4%)
2-5% in those over the age of 60 (more than 6% in patients over the age of 80)
10-30% of heart failure patients have atrial fibrillation
More common in men
What is the main mechanism by which atrial fibrillation can pose risk for significant impairments in functional capacity?
Clots can form in the atria in atrial fibrilation and pieces of these clots can cause thromboemolic events
What are some symptoms of atrial fibrillation?
May have all or some of the following symptoms:
- Fatigue
- Palpitations
- Chest pain
- Dyspnea
- Dizziness
What is the etiology of atrial fibrillation?
Caused by ectopic foci that generate electrical impulses (multiple smaller pacemakers instead of one strong SA node)
This erratic generation of electrical impulses causes an irregular ventricular rhythm
What does the AV node do to signals from the SA node?
It is a damper to the signals. It slows down the frequency of impulses in healthy and atrial fibrillation patients
What are the main classifications of atrial fibrillation?
Valvular
Non-valvular
Lone atrial fibrillation
Paroxysmal
Persistant
Longstanding persistent
Permanent
What are some causes of atrial fibrillation?
Significant disease/damage/repair to heart valves
Often use warfarin for treatment
What are some characteristics of Lone atrial fibrillation?
Absence of clinical or ECG findings:
- Other CVD (including HTN)
- Related pulmonary disease
- Cardiac abnormalities (enlargement of the left atrium)
- Age under 60
What are some charcteristics of a paroxysmal atrial fibrillation?
This is atrial fibrillation that lasts longer than 30 sec and self-terminates within 7 days
Patient is usually not in atrial fibrillation
What are some characteristics associated with persistent atrial fibrillation?
Continuous atrial fibrillation lasting longer than 7 days, but less than 1 year
What are the differences between persistent and longstanding persistent atrial fibrillation?
Continuous atrial fibrillation equal or greater than 1 year despite rhythm control management
What are the characteristics of permanent atrial fibrillation?
It is continuous atrial fibrillation for which a therapeutic deision has been made not to pursue sinus rhythm restoration (rate control alone)
How should HCPs investigate potential atrial fibrillation?
- Get history of similar episodes (get info about duration, frequency, and nature of episodes)
- Determine potential risk factors or triggers (alcohol, physical exertion)
- Identify any potential reversible causes (acute infection, drug-related) or AF secondary to another disease (acute cardiac pathology)
- Review family and medical history
- Examine patient vitals and perform physical exam
- Perform the following:
a. 12-lead electrocardiogram
b. ECG
c. Laboratory investigations
What are the goals of therapy for atrial fibrillation?
- Prevent stroke or systemic thromoembolism
- CV risk reduction
- Improve symptoms, functional capacity and QoL
- Prevent complications (LV dysfuntion and falls)
The above measures should improve survival, and reduce healthcare utilization
What is the purpose of determining a stroke risk stratification score?
- Estimate risk of stroke in patients with atrial fibrilation
- Used to determine degree of antithrombotic therapy required based on an individuals patient’s risk of developing stroke
- Estimate bleeding risk
What is CHADS2?
It is a score that helps determine risk of atrial fibrilation
The following variables help generate risk assessment:
- Recent CHF
- Hypertension
- Age over 75
- Diabetes
- History of Stroke
What is the risk reduction of warfarin in stroke?
Compared to placebo, warfarin reduces the risk of stroke by 66%