A 74-year-old man shows signs of heart failure, and the echocardiogram shows a normal ejection fraction. What is the underlying issue likely due to his history of poorly controlled hypertension?

In this scenario, the patient is a 74-year-old man who displays signs of heart failure, yet his echocardiogram reveals a normal ejection fraction. This specific situation is often indicative of heart failure with preserved ejection fraction (HFpEF), which is frequently seen in individuals with a history of hypertension.

Poorly controlled hypertension leads to an increase in the afterload, which places extra strain on the heart muscle. Over time, this increased workload causes the myocardial cells to undergo hypertrophy, leading to a thickening of the heart muscle wall. The hypertrophied myocardium can become stiffer, which impairs the heart's ability to fill properly during diastole, contributing to symptoms of heart failure despite a normal ejection fraction.

This response aligns with the underlying pathophysiology of hypertensive heart disease, where persistent high blood pressure induces changes in the heart's structure and function. Therefore, the most likely underlying issue in this patient's case is cardiomyocyte hypertrophy resulting from his history of poorly controlled hypertension.