# Heart Failure Pathology > Heart failure pathology for MBBS Pathology: forward and backward failure, eccentric versus concentric remodelling, neurohormonal cascade and cachexia. - Canonical URL: https://prepelephant.com/topics/mbbs/pathology/heart-failure-pathology - Exam / course: MBBS · Subject: Pathology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Heart Failure Pathology", PrepElephant, https://prepelephant.com/topics/mbbs/pathology/heart-failure-pathology ## Direct answer When the heart can no longer deliver output for the body's metabolic demands — or does so only at raised filling pressures — heart failure follows, and its pathology is a vicious circle: initial injury (ischaemia, hypertension, valves, myocarditis) triggers compensatory neurohormonal activation (sympathetic drive, renin-angiotensin-aldosterone) that maintains perfusion short-term but remodels the myocardium long-term, with myocyte hypertrophy, interstitial fibrosis and chamber reshaping that further depress function. Left-sided failure backs blood into the lungs (dyspnoea, orthopnoea, pink frothy sputum, haemosiderin-laden macrophages in alveoli), right-sided failure into the systemic venous bed (dependent oedema, hepatomegaly with nutmeg liver, raised jugular venous pressure), and chronic disease adds cardiac cachexia and the end-organ congestion of the kidney and liver. ## What you must remember - **Remodelling by chamber:** volume load (mitral or aortic regurgitation, dilated cardiomyopathy) drives eccentric hypertrophy — sarcomeres added in series, chamber dilatation with relative wall thinning; pressure load (hypertension, aortic stenosis) drives concentric hypertrophy — sarcomeres in parallel, thick walls with a small cavity; chronic failure of either ends in dilatation with wall thinning. - **Neurohormonal cascade and its targets:** catecholamines (tachycardia, arrhythmia, direct myocyte toxicity), angiotensin II and aldosterone (vasoconstriction, sodium retention, fibrosis), arginine vasopressin (water retention and hyponatraemia), and natriuretic peptides as counter-regulation — the basis of beta-blockers, ACE inhibitors, angiotensin receptor-neprilysin inhibition and mineralocorticoid antagonists. - **Left failure lung pathology:** chronic passive congestion — alveolar septal oedema, capillary congestion, microhaemorrhages with haemosiderin-laden macrophages when stress failure of capillaries occurs (the basis of pink frothy sputum and brown induration). - **Right failure congestion:** nutmeg liver (chronic passive congestion with centrilobular necrosis and haemorrhage), cardiac cirrhosis in extreme cases, dependent pitting oedema, pleural and pericardial effusions, gut congestion causing anorexia. - **Cellular pathology of the failing myocyte:** hypertrophy with elongation, myofibrillar loss, T-tubule disruption, apoptosis and autophagy; interstitial fibrosis by activated fibroblasts stiffens and uncouples the syncytium. - **High-output failure:** anaemia, thyrotoxicosis, beriberi, arteriovenous fistula and Paget disease demand supernormal output until the heart fails with warm extremities and wide pulse pressure — the Indian exam links it to severe chronic anaemia and wet beriberi. - **Cor pulmonale:** right ventricular hypertrophy and failure secondary to lung disease — in India, chronic obstructive pulmonary disease, tuberculosis-destroyed lungs and silicosis are standing causes. - **Cachexia and end-stage markers:** cardiac cachexia (loss of more than 5% body weight), hyponatraemia as a poor prognostic sign, and frequent terminal arrhythmia from the remodelled, fibrotic substrate. ## A cough at midnight, traced to the myocyte A 60-year-old hypertensive smoker wakes gasping after two hours of sleep, coughing pink frothy sputum; crepitations fill both lung fields and the third heart sound gallops. The chain runs backwards: acute pulmonary oedema means acutely raised left atrial pressure, which means a decompensated left ventricle, whose chronic pressure load built concentric hypertrophy until diastolic filling failed. The myocyte level explains the treatments: overactive sympathetic and renin-angiotensin signalling drove fibrosis and remodelling, so the drugs that modify the disease are precisely the ones that block that signalling — ACE inhibitor or angiotensin receptor-neprilysin inhibitor, beta-blocker once euvolaemic, mineralocorticoid antagonist — while diuretics and vasodilators only unload the acute episode. The same patient, untreated for years, returns with a tender enlarged liver, ankle oedema and raised jugular venous pressure: biventricular failure, and the liver biopsy (were it ever taken) would show centrilobular congestion — the nutmeg pattern of right-heart failure. Every physical sign in that sentence is congestion somewhere, which is why heart failure clinical teaching is haemodynamics made visible. ## Where students slip The classic slip is reciting "forward versus backward failure" as competing theories rather than two descriptions of one state — the examiner wants both used: forward failure explains fatigue, oliguria and hypotension; backward failure explains congestion. Second, students call the neurohormonal response "compensation" and stop; the v2 point is that compensation is the disease — chronic catecholamine and aldosterone exposure is myotoxic and fibrogenic, which is why blocking it (counter-intuitively, including beta-blockade in a weak ventricle) improves survival. Third, the pathological specimen slips: haemosiderin-laden macrophages belong to chronic left-sided congestion, nutmeg liver to right — mixing the two organs loses easy marks. ## Frequently asked questions ### How do eccentric and concentric hypertrophy differ? Eccentric hypertrophy adds sarcomeres in series with chamber dilatation (volume overload), while concentric hypertrophy adds them in parallel, thickening walls and reducing cavity size (pressure overload). ### Why does chronic heart failure cause hyponatraemia? Neurohormonal activation with arginine vasopressin release retains water in excess of sodium, diluting serum sodium — a marker of advanced disease and poor prognosis. ### What is the nutmeg liver of right heart failure? Chronic passive hepatic congestion with dark centrilobular regions alternating with paler periportal parenchyma, due to venous backing-up behind the failing right ventricle. ### Which conditions cause high-output heart failure? Anaemia, thyrotoxicosis, beriberi, arteriovenous fistula and Paget disease of bone — demands for supernormal output that eventually exhaust the myocardium. ### Why are beta-blockers given in chronic heart failure despite negative inotropy? Chronic sympathetic overdrive is directly myotoxic and arrhythmogenic; gradual beta-blockade reverses remodelling and reduces mortality once the patient is euvolaemic.