Focal Atrial tach = atrial fib

[PVC]

Hello I was recently seen at the Mayo clinic where an electrophysiologist indicated that my infrequent afib was probably initiated by focal atrial tachycardia.  It seems that I have frequent episodes of atrial tach that last only a few beats, unless I am exercising when it has lasted as long as 185 beats at a rate of 274 bpm.  One very peculiar symptom I have is that the atrial tach is always stimulated by the action of swallowing.  In fact the atrial tach will not occur unless I swallow (strong vagal connection).  Clearly this atrial tach is provokable.  I did have an EP study done in 1997 in London, Ontario, Canada which, unfortunately took place when the atrial tach was dormant.  It seems that every so often things go quiet.  Thus in London it could not be provoked and thus no ablation was attempted.  Recently I suffered an 11 hour afib episode that converted after IV digoxin (.5 mg over 20 min) and 450 mg oral propafenone.  Since that time (5 days) I have been left on propafenone 150 mg TID.  The swallow trigger and thus atrial tach have again gone dormant under this med.  I am now tappering off the propafenone and will be drug-free early next week.  I expect the swallowing-induced atrial tach to then return.  So my questions are:
1.  Is it an established fact that afib can be triggered by focal atrial tach?
2.  Because it is so provokable(every time I swallow) would a follow-up EP study be advisable with possible ablation of this focus?
I am only 39 and in other wise perfect health.  My heart is apparently free of any problem other than this mysterious arrhythmia (all testing negative).
Thankyou for your thoughts.
Peter

[CCF CARDIO MD - DLB]

1. Yes
2. IF the focus can be identified, ablation would be a reasonable course of action.

[Peter]

Thankyou for the quick response.  I have one other question that may be hard to answer:   The fact that my atrial tach occurs only when I swallow - does that make it all the more likely that:
a) it will be easier to identify and
b) it would be a single focus and thus easier to ablate than a more complex multi-focus.

Sorry I have one other question.  Can atrial tach result from other problems such as AVNRT, WPW etc.  It seems my history shows absolutely no ventricular problems only SVT which occassionally degenerates into afib (again always after I swallow, which triggers the atrial tach on a regular basis).  
Thankyou again.
Peter

[CCF CARDIO MD - DLB]

IF you can in fact reproduce your tachycardia during the EP study, that would make identifying it and ablating it much easier. There are other mechanisms of atrial tachycardia generation and atrial fibrillation generation that exist and coexist. Many atrial tachycardia types can be ablated. Atrial fib, unless it is in fact triggered in the manner you describe, does not lend itself well to ablation.