Drowsiness caused by a bad heart may be related to coronary heart disease, pulmonary heart disease, heart failure and other factors. 1. Coronary heart disease: when the coronary arteries are narrowed or blocked, coronary heart disease can be triggered, which will affect the blood and oxygen supply to the body, if the brain is not enough blood and oxygen, there will be drowsiness. 2. Coronary heart disease: Coronary heart disease is a heart disease caused by high pressure of pulmonary artery, persistent high pressure of pulmonary artery can lead to carbon dioxide retention, causing respiratory difficulties, and even develop into pulmonary encephalopathy, which may cause drowsiness. 3. Heart failure: Heart failure can develop from myocardial infarction, myocarditis, coronary heart disease and other diseases. Due to the impaired pumping function of the heart, the amount of blood discharged by the heart cannot meet the basic metabolic needs of the brain, so it will produce drowsiness. If drowsiness is caused by a bad heart, you should go to the hospital in time to avoid delays.