Pooled analysis of 457 patients with obstructive hypertrophic cardiomyopathy established that a 0.35 mL/kg/min increase in peak oxygen uptake represents a clinically meaningful improvement patients can perceive. The drug aficamten achieved this threshold in 60% of patients compared to just 31% receiving placebo or standard metoprolol therapy, representing a 3.4-fold higher likelihood of meaningful benefit. This finding provides the first patient-centered benchmark for measuring exercise capacity improvements in this genetic heart condition that affects approximately 1 in 500 people worldwide. Hypertrophic cardiomyopathy causes the heart muscle to thicken abnormally, restricting blood flow and reducing exercise tolerance. While previous studies measured oxygen uptake changes, this research bridges the gap between laboratory measurements and what patients actually feel as improvement in their daily activities. The establishment of this minimal important difference could accelerate development of new therapies by providing clearer treatment targets. However, as this preprint awaits peer review, the proposed thresholds require validation in independent patient populations. The findings represent an incremental but important advance in personalizing treatment assessment for this challenging cardiac condition.