Posted by Steve Giddings on May 03, 2001 at 14:46:04:
In Reply to: "late atrial flutter"/Steve Giddings posted by Carl Plaskett on May 03, 2001 at 14:45:16:
Late atrial flutter is a reported complication of the maze surgery. It is established typically when one of the cryoablation lines is not extended completely across the coronary sinus. (The coronary sinus is actually the main vein that returns blood that flows through the heart from the coronary arteries back into the right atrium. It has a distinct entry point into the ra separate from both the inferior and superior vena cavae, which return blood circulating throught the rest of the body. This vein (coronary sinus) courses laterally across the back of the heart at the base of both atria. One of the ablation lines extends down the back of the left atrium. If this ablation line is inclomplete across the vein (which can be subjectedto local cryoablation locally without risk of rupture) a reentrant pathway can be established that courses across this vein and can allow atrial flutter (but not a. fib.) to develop IF IT IS PRECIPITATED by an ectopic atrial beat which just happens to occur at a location with a direct connection to this loop, and occurs at just the right time in the contractile cycle when the loop is vulnerable. Atrial flutter is subdivided into "usual" and "unusual" subtypes. About 80% of flutter involves a relatively discrete path in the right atrium. That is why localized radiofrequency ablation (RFA) in the right atrium (you don't have to cross the atrial septum) has such a high success rate. Unusual atrial flutter can invlolve several other pathways that are usually much harder to map and ablate. ALthough the flutter that occurs after maze is typically in th "unusual" category, Most cases arise as I described above, and so are amenbale to cure by RFA, by an EP cardiologist who is familiar with this complication of the maze procedure. Cox described this specific complication and its treatment in a recent series. He had two reported cases of this compliocation since ~1995. I was (presumably) the third. McCarthy also describes late flutter as a complication. I believe those in his series wer managed with meds.
I required electrical cardioversion. You can imagine I was a bit bummed at the time. I managed to put myself in this rhythm doing short interval (Class I to fitness freaks) training for the upcoming fall head racing (3 mile long rowing/sculling races) season. To boot, I did it on the morning of my 54th birthday. The EP doc in my local cardiologist's practice group did not know of this specific complication (though he trained at Mayo, where the maze is done), and did not want to RFA me (he did offer to ablate my AV node, no thank you). I have not done anything further about this. My reasoning was- it was a rare event, it took almost two years post op to occur. It may never happen again. If it does happen again, I will go back to Georgetown and hacve the EP person there, who has worked with Cox, ablate me, or go wherever to whomever Dr. Cox suggests and be RFA'd.
It has been six months now since this occurred, I competed last fall, and even won two races. I have avoided short interval training, however.
Parenthetically, macrolide antibiotics, like zithromycin, erythromycin, can cause APC's and can increase serum levels of xanthine oxidase inhibitors, like theophylline and ...caffeine. Because your atria have been "violated" by the surgery, their electrical activity may be more difficult to detect by EKG than normal. Flutter can be difficult to distinguish from other regular supraventricular tachyhcardias in any event. There are several clinical manouvers that you can one can do to distinguish it. SOmetimes you have to resort to esophageal leads (swallowing an NG tube with electrodes) to pick up the flutter waves.
I noticed the problem initially when my HR on my monitor went to 240. It blocked down to 120 when I slowed down. I was in variable 2-3:1 block (hr between 80 and 120, but mostly 120 until the next morning, when I called my cardiologist. I was treated initially with diltiazem for rate control, put on heparin for a day and cardioverted electrically the following morning. I couldn't tolerate the dilt. Blocked my HR down to 40 with additional pauses even in flutter. I have been on nothing except anticoagulation for a short period following the episode and have been fine since.