Chapter 12: The Heart: Pathology and Disease

The Heart: Pathology and Disease educational guide provides an in-depth exploration of cardiac pathology, detailing the structural, functional, and molecular alterations that drive major cardiovascular diseases. The chapter begins by establishing the pathophysiological mechanisms of congestive heart failure, distinguishing between left-sided and right-sided failure, and explaining adaptive physiological responses such as myocardial hypertrophy and ventricular remodeling. Students will review the embryological origins and clinical hemodynamics of congenital heart defects, including left-to-right shunts like atrial and ventricular septal defects or patent ductus arteriosus, cyanotic right-to-left shunts such as Tetralogy of Fallot and transposition of the great arteries, and obstructive congenital lesions like aortic coarctation. A significant portion of the text focuses on ischemic heart disease, unpacking the pathogenesis of coronary artery atherosclerosis, stable and unstable angina pectoris, and acute myocardial infarction, alongside critical topics like post-infarction complications, reperfusion injury, and sudden cardiac death. The study material also outlines the arrhythmogenic consequences of ischemic tissue damage and genetic electrical channelopathies. Further sections dissect systemic and pulmonary hypertensive heart disease (cor pulmonale), as well as acquired valvular dysfunctions including degenerative calcific aortic stenosis, myxomatous mitral valve prolapse, rheumatic heart disease, and the varying forms of vegetative infective and nonbacterial endocarditis. The academic summary extensively categorizes primary heart muscle disorders into dilated, hypertrophic, and restrictive cardiomyopathies, while also examining infectious and immune-mediated myocarditis. Finally, the chapter addresses the etiology and morphology of pericardial effusions and acute pericarditis, primary benign and malignant cardiac tumors such as atrial myxomas and pediatric rhabdomyomas, and the pathological complications associated with cardiac transplantation and artificial mechanical devices.