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You will need more investigations -
Pain from sneeze / deep breath is not likely to be cardiac.
Rate now slow - may be from the medicines....
Or with A-fib before - may mean sick sinus
HOLTER (24 to 48 hour ambulatory monitoring) / ECHOcardiogram
/ TMT (Treadmill exercise ECG) / LABORATORY work-up – may all be necessary for further assessment and assistance.
The treating doctor may suggest them depending on need, based on his assessment of the situation.
Wishing speedy recovery