Dyspnoea occurs with exertion

Pathophysiology of HCM:

Dyspnoea occurs with exertion and may result from limitation of cardiac output due to the low end-diastolic volume of a non-compliant LV, high pulmonary venous pressure due to diastolic dysfunction, and mitral regurgitation.

Angina may result from an inability of the narrowed coronary microcirculation to supply the hypertrophied myocardium in the context of high myocardial oxygen demand associated with elevated LV systolic pressure.

Atrial fibrillation or flutter is associated with a worsening of symptoms because these patients are dependent on atrial transport due to the concomitant diastolic dysfunction, an important pathophysiological feature of HCM.

Presyncopal episodes and syncope are due to LVOT obstruction, myocardial ischaemia, inappropriate systemic vasodilation, and ventricular arrhythmias.