A 67-year-old male presents to the emergency department with complaints of palpitations, shortness of breath, and intermittent dizziness over the past week. He reports feeling generally fatigued and has noticed that his heart "races" occasionally without any obvious triggers. He denies any chest pain but admits to mild discomfort when the palpitations are most intense.

The patient has a history of hypertension, which has been poorly controlled despite being on medication for the past few years. He has not adhered strictly to his prescribed regimen. He is also overweight and leads a sedentary lifestyle. No prior history of cardiac events or surgeries is noted, although he recalls experiencing brief episodes of palpitations in the past, which resolved spontaneously.

On physical examination, his blood pressure is 150/95 mmHg, and his heart rate is irregularly irregular, with a pulse of 130 beats per minute. Auscultation reveals an irregular heart rhythm without murmurs. His ECG confirms the diagnosis of atrial fibrillation with a rapid ventricular response. Laboratory tests, including thyroid function, are within normal limits.

The patient is admitted for rate control and anticoagulation therapy, given his increased risk of thromboembolic events. After a discussion of the risks and benefits, he is started on a beta-blocker and oral anticoagulant. He is also counselled on lifestyle modifications, including weight management and the importance of medication adherence to manage his underlying hypertension and reduce the risk of future complications.

The patient is discharged with a follow-up plan for outpatient cardiology consultation to consider long-term rhythm control strategies and further evaluation for possible cardioversion, depending on his clinical stability and response to treatment.