Heart disease isn’t a single condition. It’s an umbrella term covering several distinct problems that affect the heart’s arteries, muscle, valves, rhythm, or structure. In the United States, cardiovascular disease causes 1 in every 3 deaths, killing one person every 34 seconds. Understanding the major types helps you recognize what’s actually going on when a diagnosis comes up.
Coronary Artery Disease
Coronary artery disease (CAD) is the most common type of heart disease, affecting about 1 in 20 adults age 20 and older. It develops when a sticky mixture of cholesterol, fat, calcium, and other substances gradually builds up inside the arteries that supply blood to your heart. This buildup, called plaque, hardens over time and narrows the arteries, restricting the flow of oxygen-rich blood to your heart muscle.
The process starts when something damages the artery walls. That damage can come from high blood pressure, smoking, high cholesterol, or diabetes. Once the artery lining is injured, plaque begins accumulating at the site. Over years or decades, the narrowing can become severe enough to cause chest pain during exertion (angina) or, if a plaque ruptures and a blood clot forms, a heart attack. In the U.S., someone has a heart attack every 40 seconds, and about 805,000 heart attacks occur each year.
Heart Failure
Heart failure means the heart can’t pump blood effectively enough to meet the body’s needs. It doesn’t mean the heart has stopped. It means it’s struggling, either because the muscle has weakened or because it’s become too stiff to fill properly between beats.
Doctors classify heart failure by how well the heart still pumps with each contraction, measured as an “ejection fraction,” the percentage of blood pushed out of the main pumping chamber per beat. When the heart muscle weakens and the ejection fraction drops to 40% or below, that’s heart failure with reduced pumping ability. When the heart muscle is stiff and can’t relax to fill with blood but still squeezes at 50% or above, that’s heart failure with preserved pumping ability. There’s also a middle range (41 to 49%) that falls between the two. Each type feels similar to the patient, with shortness of breath, fatigue, and fluid buildup in the legs or lungs, but they involve different underlying problems and respond to different treatments.
Arrhythmias
Arrhythmias are problems with the heart’s electrical system, the signals that coordinate each heartbeat. They fall into a few broad categories based on whether the heart beats too fast, too slow, or irregularly.
Fast Heart Rhythms
A resting heart rate above 100 beats per minute is considered tachycardia. The most common fast arrhythmia is atrial fibrillation (AFib), where chaotic electrical signals in the upper chambers produce an irregular, often rapid heartbeat. Atrial flutter is similar but more organized. Other fast rhythms include supraventricular tachycardia, which causes episodes of sudden pounding that start and stop abruptly.
More dangerous are the fast rhythms originating in the lower chambers. Ventricular tachycardia is a rapid, irregular rhythm that prevents the chambers from filling with blood properly. Ventricular fibrillation is the most life-threatening: the lower chambers tremble chaotically instead of squeezing, and blood flow essentially stops. Without immediate treatment, it’s fatal within minutes.
Slow Heart Rhythms and Extra Beats
A resting heart rate below 60 beats per minute is bradycardia. This can happen when the heart’s natural pacemaker malfunctions (sick sinus syndrome) or when electrical signals get blocked on their way through the heart. Not all slow heart rates are dangerous, as many fit people have resting rates in the 50s, but when bradycardia causes dizziness, fainting, or extreme fatigue, it needs attention.
Premature heartbeats are extra beats that feel like a flutter or skipped beat. They can originate in either the upper or lower chambers. Most people experience them occasionally, and they’re usually harmless on their own.
Valvular Heart Disease
Your heart has four valves that open and close with each heartbeat to keep blood flowing in one direction: the mitral, tricuspid, aortic, and pulmonary valves. Valve disease occurs when one or more of these valves doesn’t work correctly, and it takes two main forms.
In stenosis, the valve’s flaps (leaflets) stiffen and the opening narrows. The heart has to pump harder to force blood through the smaller opening, and over time that extra strain can weaken the muscle. In regurgitation, sometimes called a “leaky valve,” the leaflets don’t close completely, allowing blood to flow backward. The heart compensates by pumping harder, but the rest of the body may still receive less blood than it needs. Mitral valve prolapse, where the mitral valve bulges backward slightly during contraction, is one of the most common valve problems. It’s often mild and may never cause symptoms, though in some cases it leads to significant regurgitation.
Cardiomyopathy
Cardiomyopathy refers to diseases of the heart muscle itself, changing its size, shape, or stiffness in ways that impair pumping. There are three main forms, each involving a different structural change.
Dilated cardiomyopathy is the most common type. The lower chambers stretch out and weaken, becoming too floppy to pump efficiently. It can result from infections, alcohol use, genetic factors, or sometimes has no identifiable cause. Hypertrophic cardiomyopathy is the opposite problem: the heart muscle grows abnormally thick, especially in the wall between the chambers. The thickened muscle can physically block blood from leaving the heart. This type often runs in families and is a leading cause of sudden cardiac death in young athletes. Restrictive cardiomyopathy is rare. The heart walls stiffen without thickening, so the chambers can’t relax and fill with enough blood between beats. It’s sometimes caused by conditions where abnormal proteins or scar tissue infiltrate the muscle.
Congenital Heart Defects
Congenital heart defects are structural problems present at birth. They affect nearly 1% of births in the United States, roughly 40,000 babies each year. These defects alter how blood flows through the heart and out to the body, and they range widely in severity.
Some defects are relatively simple, like a ventricular septal defect (a hole in the wall between the lower chambers) or an atrial septal defect (a hole between the upper chambers). Others are complex and life-threatening: hypoplastic left heart syndrome, where the left side of the heart is severely underdeveloped, or tetralogy of Fallot, which involves four structural problems at once. About 1 in 4 babies born with a heart defect has a critical form that requires surgery or another procedure within the first year of life.
Signs in newborns can include a bluish tint to the lips or nails, fast or labored breathing, tiredness during feeding, and unusual sleepiness. Treatments have improved dramatically, but many people with congenital defects aren’t fully cured even after surgical repair and may develop related health problems over time.
Risk Factors Across All Types
Some risk factors cut across nearly every form of heart disease. High blood pressure forces the heart to work harder and damages artery walls. Unhealthy cholesterol levels, specifically high LDL (“bad”) cholesterol, fuel plaque buildup. Diabetes increases the risk of dying from heart disease compared to people without diabetes. Obesity raises bad cholesterol and triglycerides while lowering protective HDL cholesterol, and it contributes to high blood pressure and diabetes as well.
Smoking damages blood vessels directly. Nicotine raises blood pressure, and carbon monoxide from cigarette smoke reduces the oxygen your blood can carry. Even secondhand smoke exposure increases heart disease risk. A diet high in saturated fats and trans fats compounds these problems. Genetics play a role too, though families often share environments and habits alongside their genes, making it hard to separate inherited risk from learned behavior.
How Symptoms Differ by Sex
Heart disease symptoms don’t always look the same in men and women. The classic heart attack presentation, crushing chest pain, applies to both sexes. But women are much more likely to experience atypical symptoms: shortness of breath, nausea, back pain, jaw pain, or indigestion, sometimes without obvious chest discomfort at all. These less recognizable symptoms contribute to delays in seeking help and, in some cases, missed diagnoses.
How Heart Disease Is Detected
Diagnosing heart disease typically involves combining a physical exam and symptom history with imaging or electrical tests. An electrocardiogram (EKG) records the heart’s electrical activity and can reveal arrhythmias or signs of a past heart attack. An echocardiogram uses ultrasound to show how the heart’s chambers and valves are moving in real time, making it useful for detecting valve disease, cardiomyopathy, and heart failure.
Stress tests combine exercise (usually walking on a treadmill) with either an EKG, echocardiogram, or nuclear imaging to see how the heart performs under increased demand. They’re most commonly used to diagnose coronary artery disease but can also evaluate cardiomyopathy, congenital defects, heart failure, and valve problems. For people who can’t exercise, a medication-based stress test can simulate the effect of physical activity on the heart.