 A 28-year-old lady complained of palpitation, fatigue and shortness of breath on climbing stairs for 6 months. She has been well without major medical problems previously. Review of history revealed that she started on vegetarian diet for weight reduction without following a special instruction 3 years ago. Her body weight had in fact not changed and the appetite remained the same. There had been no abdominal discomfort and the bowel movements appeared normal. However, she noted heavy menstrual flow in the last 6 months. On examination, she was pale looking especially over conjunctivae, nail beds and palms. Her body height was 160 cm, body weight 52 kg, blood pressure 136/70 mmHg, and pulse rate 96/min. A venous hum was audible above the clavicles. A grade 2/6 systolic murmur was audible along the left parasternal border and a third heart sound was audible at the cardiac apex. The rest of physical examination was normal. What is your working diagnosis and how are you going to work up and advise this lady? (20%)