Thanks for the additional details. Having gone through your descriptions, I feel that there might be a remote possibility of this Atrial fib / SVT being related to speech causing speech abnormality. Please have a look at these web resources which provide authentic information about this issue:
Secondly, getting afflicted with the problem of SVT/ atrial fib is not normal in any way. Heart rhythm abnormality could possibly be the initiating event which could have led to a embolus been dislodged into the speech area of the brain (something like a minor stroke), causing the speech abnormality that you now have.
Therefore I think that you must discuss with your doctor. The following tests may be required:
(a) MRI of the brain, which may pick up any blockage/ infarct.
(b) Your doctor may also want a MRA (magnetic resonance angiography) of the brain
(c) Electrophysiological studies of the heart (which may be followed by catheter ablation which may stop the rhythm disturbances).
Depending on the cause, further management would be appropriate and beneficial to you. Moreover you have to get yourself examined for your blood pressure regularly.
I hope that this information helps. Best wishes. Kindly feel free to enquire if you have any remaining concerns or doubts and it would be my privilege to try helping you as much as I can.
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