Case # 1: 59 yr old man with HTN, CAD and bypass surgery 2 years earlier, complicated by post-operative atrial fibrillation. Presents now with palpitations and pre-syncope.
Stuart A. Winston, D.O.
Michael H. Lehmann, M.D.
Richard D. Judge, M.D.
1. Is this atrial fibrillation?
2. How do you think the rhythm relates to the symptom of pre-syncope?
Atrial flutter and atrial fibrillation can cause pre-syncope, but it is relatively uncommon. More commonly, the hypoperfusion symptom comes at the time of abrupt spontaneous termination of the arrhythmia. Above ECG is not atrial fibrillation, it's atrial fibrillation's cousin: ATRIAL FLUTTER
The rhythm in this ECG is ATRIAL FLUTTER. It also shows LVH and left anterior fascicular block, but today we'll concentrate on the flutter.
The flutter waves can usually be best seen in the inferior leads. Note the highlighted flutter waves in Lead III above. Do you see why we call this pattern "saw-toothed"? With an atrial rate this fast, some flutter waves are undoubtedly going to fall within the QRS complex (look at first and last highlighted flutter waves). There is a 3:1 or 4:1 AV conduction ratio in this ECG. When there is a 2:1 ratio (very common in flutter), every other flutter wave is often either inconspicuous or completely hidden. Now let's figure out the atrial rate.
Remembering that each small box is 40 msec and each big box is 200 msec, you can use calipers and determine that the atrial cycle length (f-f interval) is ~ 230 msec. Divide 60 by 0.230 seconds to get the rate. The answer is 260 bpm. Therefore the flutter rate is 260. Atrial flutter is often exactly 300 bpm but can be slower when the atrial size is larger or when the patient is taking an antiarrhythmic drug.
Note that though the flutter waves are very obvious in the inferior leads, they are less obvious in others.
This ECG is an example of typical (or Type I) flutter. The inferior lead flutter waves in typical flutter are negative and those found in V1 are typically positive.
The ECG strips above are obtained by a Holter monitor from this patient. Atrial flutter and atrial fibrillation can cause pre-syncope, but it is relatively uncommon. More commonly, the hypoperfusion symptom comes at the time of abrupt spontaneous termination of the arrhythmia.
Our sinus nodes are physiologically somewhat suppressed by the fast atrial rhythm of flutter or fibrillation. However, if the patient has sinus node dysfunction or if they have been given a drug for the fast rates that also suppresses sinus node function, the so-called sinus node recovery time can be even more impressive.
This patient avoided a permanent pacemaker by having his atrial flutter successfully ablated percutaneously.
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