context: Heart failure can happen when your heart is too weak to pump enough blood to the rest of your body. Some health conditions can affect how well your heart works and lead to heart failure. CAD happens when a fatty substance called plaque builds up in your arteries (the blood vessels that carry oxygen-rich blood from your heart to the rest of your body). Over time, plaque hardens and your arteries get narrow. An artery clogged with plaque is like a clogged drainpipe -- less blood can squeeze through. This is called atherosclerosis. Your heart has to pump harder to push blood through those narrow arteries, and it doesn't get the blood it needs to work as well as it should. Over time, this can make your heart so weak that it leads to heart failure. If you have CAD, a piece of the plaque that's built up in your arteries can break off. This can lead to a blood clot. If the clot gets lodged in one of the arteries bringing blood to your heart, it can block the blood flow and you could have a heart attack. Without enough oxygen, the part of the heart that's blocked can die. This damage weakens your heart and can lead to heart failure. Blood pressure is the force of blood as your heart pumps it through your arteries. When the blood pushes against your artery walls with more force than usual, you have high blood pressure. This makes your heart work harder to push blood through your body, and that extra work makes your heart bigger and weaker. High blood pressure that's not managed well can double or triple your chances of heart failure. The hormone insulin normally moves sugar from your bloodstream into your cells, where it's used for energy or stored for later. When you have diabetes, your body doesn't make enough insulin or doesn't use insulin well enough. This can leave too much sugar in your blood (high blood sugar). High blood sugar damages arteries and weakens your heart. That can lead to heart failure. People who have diabetes are also more likely to have high blood pressure and atherosclerosis. This is when your breathing pauses over and over again while you sleep. Each time you stop breathing, your brain jolts you awake to get it restarted. It may be linked to atrial fibrillation (a quivering or irregular heartbeat) and high blood pressure in your lungs, which can lead to heart failure. More than one-third of Americans are obese. That means the ratio of their weight to their height, known as body mass index or BMI, is 30 or higher. Extra weight puts more strain on your heart. Being obese also makes you more likely to have diseases linked to heart failure, such as high blood pressure, diabetes, or sleep apnea. This disease damages your heart muscle and makes it so weak it can't pump blood like it should. Cardiomyopathy can run in families, or it can be caused by coronary artery disease, a virus, or another condition. Four valves control the flow of blood into and out of your heart. They keep blood from flowing backward. If you have heart valve disease, at least one of these valves doesn't work right. The problem can start when you're born, or it can be caused by something that damages your heart, like a heart attack or an infection. When a valve doesn't open or shut the way it should, your heart has to work harder to pump blood. A valve problem that isn't treated can lead to heart failure. Your heart usually beats in a regular lub-dub pattern. The upper chambers squeeze, and then the lower chambers squeeze. When you have an irregular heart rhythm, your heart beats too quickly, too slowly, or out of rhythm. If your heart is off its beat for too long, it won't pump enough blood. This can eventually lead to heart failure. One or two drinks a day might be good for your heart, but more than that can lead to obesity, high blood pressure, and heart failure. Drugs like cocaine, amphetamines, and ecstasy ( MDMA) ramp up your heart rate and raise your blood pressure. Using these drugs can lead to a heart attack and eventually make your heart fail. Smoking also damages your heart and raises your blood pressure. The chemicals in cigarette smoke keep your blood from carrying enough oxygen through your body. That makes your heart work harder. Smoking also narrows your blood vessels and makes your blood more likely to clot. Several drugs can lead to heart failure or make it worse, including: Antidepressants -- citalopram ( Celexa) and tricyclic antidepressants Antifungal drugs -- amphotericin B ( Ambisome, Amphotec) and itraconazole ( Sporanox, Onmel) Drugs that affect your appetite Asthma medicines -- albuterol ( Proventil, Ventolin), bosentan, and epoprostenol Blood pressure medicines -- alpha-blockers and calcium channel blockers Chemotherapy drugs used to treat cancer Diabetes drugs -- metformin ( Glucophage, Glumetza) Epilepsy drugs -- carbamazepine ( Tegretol) and pregabalin ( Lyrica) Heart rhythm drugs Non-steroidal anti-inflammatory pain relievers ( NSAIDs) Migraine medicines -- ergotamine and methysergide Medication used to treat Parkinson's disease