Symptomatic arrhythmia in an older active woman

Scenario
A 70-year-old previously well and active lady presents with a two-week history of intermittent, irregular palpitations, which are worse with moderate effort such as walking up hills and heavy housework.

She says if she pushes herself she becomes quite breathless and a little dizzy.

Her GP is treating her for mild hypertension with ramipril 2.5mg per day. She is a lifelong non-smoker. Her total cholesterol is 5.6mmol/L with an LDL of 3.8mmol/L.

On physical examination, she has a pulse rate of 64 beats per minute, which seems irregularly irregular and a BP of 135/80. There is a