1. Atrial Fibrillation
Ameer Ahmed

2. Objectives
Identify patients with A-Fib in two cases
Define Atrial Fibrillation
Compare and contrast A-Fib and Atrial Flutter
See what A-Fib looks like on an EKG
Learn about the different types of A-Fib
Understand the causes of A-Fib
Analyze graphs

3. Examining a Patient
 65 year-old male
 Patient History:
 Heart Attack
 Stented
 Sleep Apnea
 All of these, including the abnormal EKG, showed that
the patient had atrial fibrillation

4. What is Atrial Fibrillation?
 The 2 top chambers of the heart receive quick irregular
electrical signals, causing fast and irregular contraction
 It is the most common type of arrhythmia
 Approx. 33% of arrhythmia-related
hospitalizations are A-Fib
 A-Fib increases the risk of stroke 5x and the risk of
death 2x

5. Atrial Fibrillation vs. Atrial Flutter
 Atrial Fibrillation
 Variable in amplitude, shape, and timing
 Not a reentrant circuit-comes from different
activation points
 Atrial Flutter
 The electrical signals travel in a reentrant
circuit, causing the upper two chambers to
beat faster than the lower two chambers
 A loop that keeps reactivating

7. Electrocardiographic Features
 Without negative dromotropic agents, ventricular rate
is between 100 and 160 bpm
 On an EKG, the “f waves” are variable in amplitude,
shape, and timing

8. Electrocardiographic Features
 However, when the ventricular rate is very fast (rate>
170 bpm), then the f waves can seem weaker and look
like they fall into a rhythm, giving the impression that
atrial fibrillation is NOT present

9. Normal EKG

10. Abnormal EKG with Atrial Fibrillation

11. Classification of Atrial Fibrillation
 First Episode
 First occurrence of AF
 Recurrent
 More than 2 episodes of AF
 Paroxysmal
 Ends within 7 days
 Persistent
 Present continuously for 7+ days

12. Classification of Atrial Fibrillation
 Longstanding (Persistent)
 Present for longer than 1 year
 *Permanent (Accepted)
 Longstanding A-Fib refractory to cardioversion
 Note: “Permanent AF” does not have to be
permanent as it can be cured by surgical or
catheter ablation

13. Mechanisms of Atrial Fibrillation
 Drivers
 Send rapid electrical signals
 Circuits
 Terminate and change wavelets, continuing
the irregular electrical activity
 In many studies, the left atrium has the dominant
frequency discharge (left-to-right gradient)

14. Genetic Factors of Atrial Fibrillation
 Many mutations responsible for AF have been identified
 Gain of function of repolarization of
Potassium currents that cause shortening of
atrial response and facilitation of atrial
reentry
 Atrial responsefaster top chambers vs.
bottom chambers

15. Genetic Factors of Atrial Fibrillation
 Many polymorphisms, connected to structural heart
disease, have been identified to affect Sodium and
Potassium channels to predispose to AF

16. Causes of Atrial Fibrillation
 Hypertension (usually left ventricular)
 Risk increased by heart diseases:
 Ischemic heart disease
 Mitral valve disease
 Hypertrophic cardiomyopathy
 Dilated cardiomyopathy
 Induced by tachycardia

17. Causes of Atrial Fibrillation
 Obesity and Sleep Apnea increase risk of AF
 Temporary:
 Alcohol
 Surgery

20. Examining a Patient with Arrhythmias
 45 year-old female
 Stress test given
 Heart rate increase
 Heart rate increased while sleeping. Subtle
enough not to wake her, but noticeable when
awake
 Diagnosis is that she has atrial fibrillation
 Echocardiogram shows irregular beats, but nothing
continuous
 As it turns out, she had atrial flutter, not atrial
fibrillation

21. Personal Impact/Conclusion
 Observing for the past 2 weeks has given me a great
amount of insight into the world of cardiology
 My passion for cardiology has increased even more
 I have learned more presentational skills by
participating in this project
 I met some wonderful people who taught me a great
deal of life lessons

22. References List
 Heart Disease: A Textbook of Cardiovascular Medicine ;
Braunwald's Heart Disease. Review and Assessment.
Philadelphia: Saunders, 1998. Print.
 http://meds.queensu.ca/central/assets/modules/ECG/norma
l_ecg.html
 http://lifeinthefastlane.com/ecg-library/hyperthyroidism/
 http://lifeinthefastlane.com/ecg-library/atrial-fibrillation/
 http://www.learntheheart.com/cardiology-review/atrial-
fibrillation/