ECG 診斷：
Atrial flutter with 2:1 and 3:1 block
Circulation ECG Challenge Response! Regarding the 56 year old woman with AF and palpitations:
Diagnosis: atrial flutter with 2:1 and 3:1 AV block
There is a regular rhythm at a rate of 130 bpm. There are several longer RR intervals (↔). The QRS complex duration is normal (0.08 sec) and the morphology is normal. The axis is normal between 0° and +90° (positive QRS complex in leads I and aVF). The QT/QTc intervals are normal (280/410 msec). There are P waves seen, primarily in lead V1 (+) and there is a short RP (┌┐) and long PR (└┘) interval. Etiologies for a short RP interval include:
1. sinus tachycardia
2. atrial tachycardia
3. ectopic junctional tachycardia
4. atrial flutter with 2:1 AV conduction
5. typical atrioventricular nodal repentant tachycardia (unusual variant termed slow-slow)
6. atrioventricular reentrant tachycardia
During the longer RR intervals (↔) two sequential P waves can be seen (+, ^). They have a stable PP interval at a rate of 260 bpm. The only atrial arrhythmia that has a regular rate ≥260 bpm is atrial flutter. Therefore there is 2:1 and 3:1 AV block.
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