The heart is a muscular organ that functions as a sophisticated physical pump, relying on four chambers, four valves, and a robust muscular wall to circulate blood efficiently throughout the body. Structural Heart Disease (SHD) is a broad term referring to a variety of conditions that involve a defect or abnormality in these physical components of the heart, or the major blood vessels immediately connected to it. These defects compromise the heart’s ability to move blood forward, often leading to significant strain on the organ over time. While some structural issues are present from birth, others develop later in life due to wear and tear, infection, or other underlying health conditions.
What Defines Structural Heart Disease
Structural heart disease specifically addresses problems with the organ’s architecture, essentially the “plumbing” of the heart, rather than its electrical system. The components considered part of the heart’s structure include the four heart valves, the muscular walls of the four chambers, and the septa, which are the dividing walls between the left and right sides. When these physical structures are damaged, they may cause an obstruction, allow blood to leak backward, or create abnormal connections between chambers. The functional consequence of SHD is always inefficient blood flow, forcing the heart muscle to work harder than normal to meet the body’s demands.
Structural integrity is measured by how well the valves open and close, the chambers maintain their proper size and shape, and the walls remain whole. When a valve narrows, a condition called stenosis, it obstructs blood flow and increases pressure in the preceding chamber. Conversely, when a valve fails to close completely, known as regurgitation, blood leaks backward, which also causes the heart to pump the same volume of blood multiple times.
Major Categories of Structural Heart Conditions
Structural heart disease manifests in three primary ways that categorize the specific type of defect a person may have. Valvular heart disease is one major category, involving problems with the four valves that regulate blood flow, including the aortic, mitral, tricuspid, and pulmonary valves. Aortic stenosis, where the aortic valve becomes stiff and narrowed, is a common example, forcing the left ventricle to generate extreme pressure to push blood out to the body. Mitral regurgitation is another frequent issue, involving the mitral valve failing to close tightly, which allows blood to flow backward into the left atrium during a heartbeat.
Another significant category is Cardiomyopathy, which is a disease of the heart muscle itself, affecting the walls and chambers. This condition alters the heart’s ability to contract and relax, such as in dilated cardiomyopathy, where the chambers become stretched and thin. Hypertrophic cardiomyopathy, by contrast, causes the muscle walls to thicken abnormally, making it difficult for the heart to fill with blood between beats. These conditions compromise the heart’s pumping action and can lead to heart failure.
The third main category is Congenital Heart Defects, which are structural issues present at birth, even though they may not cause symptoms until later in adulthood. These defects often involve holes in the septa, such as an Atrial Septal Defect (ASD) or Patent Foramen Ovale (PFO), which allow oxygen-rich and oxygen-poor blood to mix. These defects alter the pressure dynamics within the heart, causing strain on the lungs or heart chambers.
Underlying Causes and Common Symptoms
Structural heart disease can arise from various factors, with some conditions developing over a person’s lifetime and others originating before birth. Aging is a frequent cause of acquired SHD, as the continuous stress of the heart beating can lead to calcification and wear-and-tear on the valves, most commonly affecting the aortic valve. Infections can also cause structural damage, particularly rheumatic fever, which can scar the heart valves years after the initial streptococcal infection, or endocarditis, which is a bacterial infection of the inner lining of the heart and its valves. Hypertension and previous cardiac events, such as a heart attack, also contribute to SHD by damaging or scarring the heart muscle, altering its structure and function.
When the heart’s physical components fail, the body begins to experience common symptoms of inadequate circulation and increased pressure. Shortness of breath, or dyspnea, is a frequent complaint, occurring because the failure of a valve or muscle causes blood to back up into the lungs. Chronic fatigue results from the body’s tissues not receiving enough oxygenated blood, which is a direct consequence of the heart’s inefficient pumping. Swelling in the extremities, known as edema, is another indicator of structural failure, as the heart struggles to return fluid from the body’s periphery back to the central circulation.
Diagnosis and Modern Treatment Options
Diagnosis of structural heart disease typically begins with non-invasive imaging to visualize the heart’s internal architecture and assess its function. The echocardiogram, which uses sound waves to create live-action images of the heart, is the primary diagnostic tool, allowing physicians to measure chamber size, assess valve motion, and calculate blood flow velocity. Cardiac Computed Tomography (CT) and Cardiac Magnetic Resonance Imaging (MRI) provide highly detailed, three-dimensional maps of the heart and great vessels, allowing for precise tissue characterization and measurement of calcium deposits on the valves. Cardiac catheterization is an invasive procedure where a thin tube is inserted into a blood vessel and guided to the heart, enabling direct measurement of pressures within the chambers and vessels, which is often necessary to confirm the severity of the structural defect.
Treatment for structural heart disease spans from medical management to physical repair or replacement of the damaged structure. Medications are often used to manage symptoms and reduce the strain on the heart, such as diuretics to reduce fluid buildup or beta-blockers to regulate heart rate and blood pressure. For many structural issues, the definitive treatment involves a physical intervention, traditionally performed through open-heart surgery. However, modern interventional cardiology has introduced numerous catheter-based procedures that are significantly less invasive, offering faster recovery times.
These minimally invasive techniques rely on guiding instruments through a small puncture in the groin or chest to reach the heart. Transcatheter Aortic Valve Replacement (TAVR) is a widely adopted procedure that replaces a stiff aortic valve by inserting a prosthetic valve via a catheter, without the need to surgically remove the old valve. For mitral regurgitation, the MitraClip procedure uses a catheter to deliver a small clip that fastens the leaflets of the mitral valve, helping them close more effectively to reduce backward blood flow. Congenital defects like ASD or PFO can also be closed percutaneously by delivering a small closure device through a catheter, physically patching the hole in the septal wall.