From inflammation to a rigid cage
Constrictive pericarditis is the long-term scar of healed inflammation. After repeated or severe pericarditis — classically from tuberculosis, but also from radiation, prior heart surgery, or chronic inflammation — the pericardium thickens, scars, fuses its two layers together, and may even turn to bone-hard calcium. The flexible sac becomes a rigid shell locked around the heart.
The problem is the same theme as the rest of this track — impaired filling — but with a different mechanism. In tamponade, fluid pressure squeezes throughout the cycle. In constriction, the heart fills freely at first in early diastole, then slams to an abrupt stop when it hits the limit of the unyielding shell. The chambers simply cannot expand past the rigid cage, so filling is cut short.
A slow, deceptive picture
Because the cage tightens over months or years, the symptoms creep up slowly and look exactly like right-sided heart failure: a swollen belly, leg swelling, fatigue, breathlessness on exertion. People are often investigated for liver or kidney disease before the pericardium is even suspected. The giveaway is a markedly raised jugular venous pressure — the neck veins stand up high — combined with a heart that is not enlarged and pumps normally.
Two distinctive signs point at the rigid shell. Kussmaul's sign is a neck-vein pressure that paradoxically *rises* with inspiration instead of falling — the stiff sac won't let the right heart accept the extra venous return that breathing in normally brings. And on listening, a pericardial knock may be heard: a sharp early sound as filling abruptly halts against the shell. Together these say the muscle is fine; the wrapper is the cage.
Proving it and fixing it
Imaging seals the diagnosis. A chest X-ray may show a rim of calcium outlining the heart. Echocardiography reveals the muscle squeezing normally while filling stops short, plus exaggerated swings in flow across the valves as the two ventricles compete inside the fixed shell. A cardiac MRI or CT measures the thickened pericardium directly and is especially good at separating constriction from restriction.
Mild cases may be eased with diuretics to relieve congestion, but the definitive cure is surgical: pericardiectomy, peeling the rigid shell off the heart so the chambers can expand again. It is a major operation, but for the right patient it can transform a slow decline back into a normal-functioning heart freed from its cage.