Since 1928, the New York Heart Association Functional Classification has been the system most widely accepted worldwide for assessing the severity of cardiac or cardiovascular disease, and evaluating the patient's response to treatment. This book sets out a diagnostic classification system for heart disease. The book is presented in six sections. The first four define the five components of any diagnosis: what is the cause? (aetiologic diagnosis); what is the structural anomaly? (anatomic diagnosis); what is the functional abnormality? (physiologic diagnosis); and how severe are the symptoms and what do the lab tests show? (functional capacity and objective assessment). These last two items, which summarize the clinical findings, constitute the two-part NYHA Classificabon for grading disease severity and tracking a patient's response to treatment. The fifth section discusses uncertain diagnosis. The sixth section, new to this edition, covers diagnostic techniques that have become standard since the last revision. Other changes in the ninth edition are a thorough updating of the biology of heart disease and a discussion on ventricular diastolic dysfunction. This edition restores the functional capacity component of the classification (dropped from the past two editions) and introduces an objective assessment category.