Patho 12: The Heart

This episode explores cardiac pathology as failure of coordination between structure, blood supply, electrical activity, and mechanical demand. The heart is not simply a pump. It is a responsive organ that must adapt continuously to changing workload, pressure, and metabolic need. Disease emerges when adaptation is exceeded or misdirected.The episode begins with ischaemic heart disease as the dominant pathology of the myocardium. Coronary artery atherosclerosis is revisited briefly, but the focus shifts to myocardial response. Reversible ischaemia, infarction, and chronic scarring are traced as stages of injury shaped by duration, severity, and collateral circulation. The episode highlights how myocardial cells tolerate limited stress but fail abruptly once oxygen debt becomes critical.Myocardial infarction is explored in depth. Patterns of necrosis, inflammatory response, healing, and remodelling are followed over time. The structural consequences of infarction, including wall thinning, ventricular aneurysm, papillary muscle dysfunction, and rupture, are examined as predictable outcomes rather than rare complications.The episode then turns to cardiomyopathies. Dilated, hypertrophic, and restrictive forms are presented as distinct mechanical problems with different causes and consequences. Genetic mutations, pressure overload, toxic injury, and infiltrative disease are linked to altered chamber geometry and impaired filling or ejection.Valvular heart disease is examined as pathology of flow direction and resistance. Stenosis and regurgitation are framed in terms of pressure overload, volume overload, and downstream adaptation. The episode emphasises how valves fail gradually, allowing compensatory changes that eventually become maladaptive.Finally, disorders of rhythm and conduction are introduced as failures of electrical coordination. While not explored exhaustively, arrhythmias are presented as consequences of structural disease, ischaemia, fibrosis, and chamber dilation rather than isolated electrical faults. Cardiac pathology is therefore framed as integrated failure of structure, supply, and timing.Key takeaways* Cardiac disease reflects imbalance between demand, supply, and structure* Ischaemic injury progresses through predictable temporal stages* Myocardial infarction produces mechanical and structural complications* Cardiomyopathies alter chamber geometry and function* Electrical disturbances often arise from underlying structural disease This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe