Mr. K is a 74-year-old man who presents to the emergency department complaining of progressively worsening dyspnea when walking briskly and climbing stairs. His grand daughter reports that he has become increasingly fatigued over the last few days. He must rest several times while walking to the train station on his commute to work, whereas 6 months ago he could easily walk to the station without resting. He finds himself awakening frequently at night feeling ‘heaviness in the chest’. His past medical history is significant for myocardial infarction 5 years ago. On examination, he is overweight (BMI 34 kg/m2)), heart rate is 93 bpm, and blood pressure (BP) is 174/89 mm Hg. Physical examination is significant for a 2/6 systolic murmur at the apex without gallop.You ordered some diagnostic tests. Patient’s ECG shows left ventricular hypertrophy and left atrial enlargement. Echocardiogram shows left ventricular systolic dysfunction with ejection fraction of 35% with global hypokinesis. There is concentric left ventricular hypertrophy (LVH) and mitral annular dilatation with mitral regurgitation. As you discuss the diagnosis with the patient, the patient’s granddaughter, who is a major in Biochemistry, asks you to explain the natural history of this disorder. Which of the following is true concerning the development of this disorder?
