Restrictive Cardiomyopathy: Contemporary Insights into Pathophysiology, Diagnostic Complexity, and Evolving Therapeutic Perspectives

Restrictive cardiomyopathy represents one of the most challenging phenotypes within the spectrum of myocardial diseases, distinguished by impaired ventricular filling due to increased myocardial stiffness while preserving near-normal systolic function during early stages. Although considered uncommon, it carries a disproportionately high morbidity and mortality burden owing to its subtle clinical onset, heterogeneous etiologies, and frequently delayed diagnosis. Advances in multimodal imaging, myocardial tissue characterization, and molecular diagnostics have reshaped current understanding of this entity, revealing intricate associations with infiltrative, fibrotic, storage, and radiation-induced myocardial injuries. The clinical trajectory is typically dominated by progressive diastolic dysfunction, biatrial enlargement, preserved ejection fraction heart failure physiology, and variable conduction system involvement. Despite these characteristic features, restrictive cardiomyopathy remains diagnostically elusive, often requiring integration of echocardiography, cardiac magnetic resonance, endomyocardial biopsy, and biomarker profiling. Therapeutic strategies continue to evolve, transitioning from purely supportive management to etiology-directed interventions, including novel pharmacologic agents and targeted therapies for infiltrative and genetic subtypes. This article provides an extensive review of the contemporary understanding of restrictive cardiomyopathy, emphasizing its complex pathophysiology, diagnostic challenges, and emerging therapeutic horizons.