A cross-sectional analysis of 57 patients who underwent surgical repair for coarctation of the aorta revealed that lower heart rates independently predicted greater left ventricular wall thickness, even when central blood pressure remained normal. Computational modeling demonstrated that a 10% heart rate increase reduced posterior wall hypertrophy prevalence from 30.9% to 2.4%, suggesting heart rate modulates wave reflection timing that affects cardiac remodeling. This finding challenges conventional wisdom that heart rate reduction always benefits cardiovascular health. While lower resting heart rates typically indicate cardiovascular fitness and longevity in healthy populations, this research suggests the relationship may be more complex in individuals with congenital heart defects. The mechanism appears related to how heart rate affects the timing of arterial pressure wave reflections, which can influence ventricular workload independent of overall blood pressure. These insights could inform post-surgical monitoring and treatment strategies for the growing population of adults living with repaired congenital heart disease. However, as this is a preprint study awaiting peer review with a relatively small sample size, these provocative findings require validation in larger cohorts before clinical practice changes.