Triggers of atrial fibrillation

  Atrial premature beats - APC ( most common )

  Atrial flutter

  Supraventricular tachycardias

  Bradycardia

  Acute atrial stretch.







ECG 1a. Above is a 3-channel Holter tracing from a middle-aged woman with attacks of palpitation.
Holter recording showed multiple episodes of paroxysmal atrial fibrillation.
Atrial premature beat initiates atrial fibrillation.
Atrial premature beat is the most frequent trigger of atrial fibrillation.

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ECG 1b. Above is another strip from her Holter recording.
Atrial premature beat initiates atrial fibrillation.
The first 2 QRS complexes are
aberrantly conducted (Ashman phenomenon).

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ECG 1c. Above is another strip from her Holter recording.
The first atrial premature beat is aberrantly conducted , but it cannot initiate atrial fibrillation.
Second atrial premature beat initiates atrial fibrillation. The first 2 QRS complexes are aberrantly conducted
(
Ashman phenomenon).

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ECG 1d. Above is another strip from her Holter recording.
Every atrial premature beat
cannot initiate atrial fibrillation.
The first and second atrial premature beats are conducted aberrantly, but they cannot initiate atrial fibrillation.
The third atrial premature beat initiates atrial fibrillation of which the first 2 QRS complexes show aberration.
(
Ashman phenomenon).

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ECG 1e. Above is another strip from her Holter recording.
Sometimes paroxysms of atrial fibrillation may last very short(as seen above).
The first atrial premature beat initiates atrial fibrillation.
The following two QRS complexes are
aberrantly conducted (Ashman phenomenon).
Sinus rhythm resumes after 6 beats of atrial fibrillation.

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ECG 1f. Above is another strip from her Holter recording.
Fibrilloflutter.
While the left left side of the ECG shows atrial flutter, the rhythm then changes to atrial fibrillation on the right side of the ECG.

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ECG 2. The Holter rhythm tracing above is from another middle-aged woman.
This is another example of a very short lasting episode of atrial fibrillation.
The first atrial premature beat initiates atrial fibrillation.
The first 2 QRS complexes are conducted
aberrantly (Ashman phenomenon).
Sinus rhythm resumes in a very short time.

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ECG 3a. The above rhythm tracing is from a middle-aged man who had undergone aortic valve replacement for severe
aortic stenosis.
The very first beat on the left side is a sinus beat.
The first atrial premature beat is blocked since it is "too" premature.
It also could not initiate atrial fibrillation.
It is followed by a short-lasting episode of ectopic atrial tachycardia with negative P waves.
The ectopic atrial tachycardia is followed by a
sinus beat and then atrial fibrillation starts.
The sweep speed of this Holter recording is 25 mm/second.

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ECG 3b. The above rhythm Holter tracing is the continuation of the tracing in ECG 3a.
The last beat of the ectopic atrial tachycardia is followed by a sinus beat. Meanwhile, a pause of 1.1 seconds developes.
Then,
the following atrial premature beat initiates atrial fibrillation.
The sweep speed of this Holter recording is 25 mm/second.

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ECG 3c. The above rhythm tracing is derived from the ECG 3b, but it is displayed at a sweep speed of 50 mm/second.
The calibration is also increased.
The last beat of the ectopic atrial tachycardia is followed by a sinus beat. Meanwhile, a pause of 1.1 seconds developes.
Then,
the following atrial premature beat initiates atrial fibrillation.

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ECG 4. The above rhythm Holter tracing belongs to another middle-aged man.
An
atrial premature beat during sinus tachycardia initiates atrial fibrillation.
The sweep speed of this Holter recording is 25 mm/second.

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ECG 5a. The ECG above belongs to a 62 years-old woman with hypertension and coronary artery disease.
The patient is also having chemotherapy and radiotherapy for lung cancer.
She complains of palpitation.
There is a single
atrial premature beat (APC) in the above ECG.
An atrial premature beat may have
prolonged PR interval, as in the case above.

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ECG 5b. The ECG above belongs to the same woman.
Four
atrial premature beats deform the preceding T waves.
These
atrial premature beats have prolonged PR intervals.

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ECG 5c. The ECG above belongs to the same woman. Some
sinus beats are seen.
An atrial premature beat deforms the preceding T waves but fails to initiate atrial fibrillation
while
some atrial premature beats initiate short-lasting episodes of atrial fibrillation.

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ECG 5d. The ECG above belongs to the same woman. Some
sinus beats are seen.
Some atrial premature beats deform the preceding T waves but fail to initiate atrial fibrillation
while
an atrial premature beat initiates a short-lasting episode of atrial fibrillation.

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ECG 5e. The ECG above belongs to the same woman. Some
sinus beats are seen.
Some atrial premature beats deform the preceding T waves but fail to initiate atrial fibrillation
while
an atrial premature beat initiates a short-lasting episode of atrial fibrillation.

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ECG 5f. The ECG above belongs to the same woman.
Sinus beats and atrial premature beats
initiating atrial fibrillation
with short-lasting episodes of atrial fibrillation are seen.

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ECG 5g. The ECG above belongs to the same woman.
There are sinus beats with short-lasting episodes of atrial fibrillation.

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ECG 5h. The ECG above belongs to the same woman. The first 3 beats are
sinus beats, followed by
an
atrial premature beat initiating atrial fibrillation.

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ECG 5i. The ECG above belongs to the same woman. Sinus beats, frequent atrial premature beats and
a short-lasting episode of atrial fibrillation are seen.

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ECG 5j. The ECG above belongs to the same woman. The rhythm is atrial fibrillation.
No sinus beats, no atrial premature beats.

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ECG 6a. Above is an ECG from a 36 years-old man with no structural heart disease.
He complains of recent-onset palpitation attacks.
Between
attacks of atrial fibrillation, short-lasting sinus rhythm and an atrial premature beat are seen.

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ECG 6b. Above ECG belongs to the same man.
Short-lasting episode of atrial fibrillation is seen.

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