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11 Cards in this Set
- Front
- Back
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What are the symptoms associated with afib? |
Asymptomatic Irregular heartbeat/skipping Palpitations - heart flopping around in chest Fatigue/exercise intolerance Lightheadedness SOB Anxiety Angina |
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What is the epidemiology of afib?
What are the biggest risk factors? |
Percentage of people with afib is increasing dramatically over the past few years and is projected to double by 2050
Major risk factor is age. Developing as a risk factor is obesity. |
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What are some likely etiologies of afib? |
MI, LVH, HTN, CHF, smoking, diabetes, OSA |
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How can afib be classified? |
Paroxysmal - ≥2 episodes with spontaneous termination w/in 7 days Persistent - continuous for 7 days Long-standing persistent - continuous >1year Permanent - cardioversion has failed |
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What is the number one concern with a patient with afib? |
Stroke
The left atrial appendage doesn't contract, allowing blood to clot and those clots can be thrown to the brain. |
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What are the predictive factors for thromboembolic risk in afib patients?
How do we use risk to inform treatment? |
Prior CVA Diabetes HTN CAD CHF Advanced age
Presence of afib and ≥2 risk pts --> warfarin |
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What is the standard treatment for afib? |
Start on an AV nodal blocker (ß blocker or similar)
Make a decision about anticoagulation |
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What is the substrate hypothesis for the pathophysiology of afib? |
Afib is maintained by multiple reentry wavelets (critical number is ≥6)
Wavelength must be sufficiently short to allow reentry. Determined by refractory time and conduction speed. Low refraction and slow conduction contribute to afib |
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What might lead to slow conduction in the atria?
What might cause long refractory time?
How does atrial size affect reentry? |
Atrial scarring (from injury or aging) can slow conduction.
Vagal tone (vomiting, OSA) can increase refractory period.
Larger atria means more room for reentry. |
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What are the therapy options for afib? |
Cardioversion - works but recurrence rate is 100% within two years Medication - only helps 50% of patients maintain sinus rhythm Surgical/invasive - Maze procedure; pulmonary vein cautery isolation |
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Why is it thought that pulmonary vein cautery works? |
The border between atrial muscle and PV endothelium is rough. The muscle fibers that trace up into to the PV have their own electrical activity which can trigger wavelets and drive afib. |
