There is no direct clinical relationship between pacemaker installation and swollen feet. Swelling of the feet is most likely due to heart failure, obstruction of venous or lymphatic reflux in the lower extremities, and medication side effects. 1. Heart failure: patients with heart failure before pacemaker installation or right heart failure after pacemaker installation may experience edema and/or swollen feet in the lower extremities due to the inability of venous blood to return smoothly, which causes increased pressure in the veins and the entry of body fluids into the tissue spaces. 2. Localized swelling of the lower limbs: some patients have embolic phlebitis of the lower limbs, lymphangitis and other diseases, which can cause obstruction of venous and lymphatic reflux in the lower limbs, leading to swelling of the feet due to the entry of body fluids into the tissue space. 3. Drug side effects: some antihypertensive drugs side effects can cause swelling of the feet, common diphenhydramine class of antihypertensive drugs, such as amlodipine, nifedipine, etc., after the use of the drug may dilate the capillaries, resulting in increased permeability of the capillaries, triggering edema of the feet. There are more reasons for foot swelling after installing a pacemaker, and it is recommended to seek timely medical treatment for serious cases.