right-sided heart failure
The right side of the heart collects used, oxygen-poor blood returning from the body and sends it to the lungs. When it weakens, blood dams up behind it throughout the body's veins — so instead of soggy lungs, you see swollen legs, a bloated belly, and bulging neck veins.
Because the right ventricle cannot clear the blood arriving from the great veins, pressure rises in the systemic venous system. Fluid leaks out of capillaries into the tissues, producing pitting edema of the ankles and legs, congestion of the liver (sometimes with discomfort and abnormal liver tests), fluid in the abdomen (ascites), and a visibly raised jugular venous pressure in the neck.
The single most common cause of right-sided heart failure is left-sided heart failure pushing pressures back through the lungs. Other causes act on the right ventricle more directly, including chronic lung disease and pulmonary hypertension (together called cor pulmonale), right ventricular infarction, and certain valve and congenital heart problems.
Right-sided congestion tends to spare the lungs of fluid but loads the rest of the body. A patient may gain several kilograms of fluid weight before swelling becomes obvious — daily weighing helps catch it early.