Hypertrophic Cardiomyopathy LVH Deep Q-Waves

A 28-year-old male athlete presents to the cardiology clinic for screening after his 32-year-old brother suffered sudden cardiac death during a football match. On examination, a harsh crescendo-decrescendo systolic murmur is heard at the left sternal border that increases with Valsalva maneuver. His 12-lead ECG is shown in the diagram. The pattern marked **A** — showing left ventricular hypertrophy with deep narrow inferolateral Q-waves and T-wave inversions — is characteristic of which condition?