A 48-year-old woman presents to her primary care provider for a routine check-up, reporting a several-month history of intermittent 'skipped beats' and a sensation of rapid fluttering in her chest, particularly noticeable during periods of increased work stress. She denies chest pain, shortness of breath, or syncope. She mentions she has recently increased her intake of energy drinks to cope with long hours at work. Her vital signs include a temperature of 36.8°C, blood pressure of 128/78 mmHg, pulse of 108 beats/min, respiratory rate of 16/min, and oxygen saturation of 98% on room air. Physical examination reveals an irregularly irregular pulse with no murmurs, rubs, or gallops. Lungs are clear to auscultation. An electrocardiogram is obtained, showing an underlying sinus rhythm with frequent premature beats characterized by early, abnormally shaped P waves followed by a narrow QRS complex. What is the most likely diagnosis and the most appropriate initial management strategy?