The human heart functions as a complex, four-chambered pump, composed of muscular walls, specialized chambers, and four delicate valves. When this intricate mechanical structure is compromised by damage or a defect, the heart’s ability to pump efficiently is impaired. This condition, which affects the physical integrity of the cardiac apparatus, is broadly defined as Structural Heart Disease (SHD).
Defining Structural Heart Disease
Structural Heart Disease refers to conditions that involve defects or damage to the heart’s physical components, including its valves, walls, chambers, and the major vessels connected to it. SHD is distinct from Coronary Artery Disease (CAD), which involves plaque buildup in the arteries supplying the heart muscle. It is also separate from primary electrophysiological disorders, which are problems with the heart’s electrical signaling that cause irregular heartbeats. A structural issue means a part of the organ is physically malformed or damaged, impairing its function of directing and propelling blood.
Common Forms of Structural Disease
The most prevalent category of Structural Heart Disease involves the heart’s four valves, which control the one-way flow of blood between chambers and out to the body. Valvular issues commonly manifest as stenosis or regurgitation. Stenosis occurs when a valve opening narrows, restricting blood flow and forcing the heart to exert more pressure. Regurgitation, or a “leaky” valve, happens when the valve flaps fail to close completely, allowing blood to flow backward into the previous chamber.
Septal Defects involve abnormal openings in the walls that separate the heart’s chambers. The most common examples are an Atrial Septal Defect (ASD) or a Ventricular Septal Defect (VSD), which are “holes” in the wall between the upper or lower chambers, respectively. A common variant is a Patent Foramen Ovale (PFO), a small opening between the upper chambers that fails to close properly in about one in four people. These defects allow oxygen-rich and oxygen-poor blood to mix, which can strain the heart and lungs.
Diseases of the heart muscle, Cardiomyopathy, alter the physical shape and function of the organ. Hypertrophic cardiomyopathy causes the heart muscle to become abnormally thick, making it stiff and reducing its capacity to fill with blood. Conversely, Dilated cardiomyopathy causes the chambers to stretch and thin, weakening the muscle and making it unable to pump blood effectively. Structural issues can also affect the Aorta, the body’s main artery, such as an Aortic Aneurysm where the vessel wall weakens and bulges outward.
How Structural Heart Disease Develops
Structural Heart Disease origins are categorized into congenital defects and those acquired later in life. Congenital defects are structural abnormalities that form during fetal development, affecting approximately one percent of all births. The exact cause is often unknown, but these conditions are linked to genetic factors, chromosomal abnormalities, or exposure to certain maternal health conditions or substances during pregnancy.
Acquired SHD develops over the lifespan, often driven by age-related degeneration. This is particularly true for valvular diseases like aortic stenosis, where calcium deposits accumulate on the valve leaflets, causing them to stiffen and narrow. Infections can also cause structural damage, notably Rheumatic Fever, which can permanently damage heart valves, or infective endocarditis, where bacteria directly attack the valve tissue.
Chronic strain on the heart, such as from uncontrolled high blood pressure, forces the heart muscle to work harder against increased resistance. This chronic overwork can lead to structural changes, including thickening of the muscular walls or dilation of the chambers, contributing to cardiomyopathy. Atherosclerosis, the hardening and narrowing of arteries, can also contribute to acquired structural deterioration.
Identifying and Treating Structural Issues
Diagnosis relies heavily on imaging tools that allow physicians to visualize the heart’s physical architecture. The Echocardiogram, which uses sound waves to create a moving image, is the primary diagnostic instrument used to assess valve function and chamber wall integrity. More detailed imaging, such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), provides highly precise anatomical measurements of the heart and surrounding vessels.
Treatment strategies for SHD range from medication management to complex interventional procedures and open surgery. Medications are primarily used to manage symptoms and associated conditions, such as diuretics to reduce fluid retention or beta-blockers to regulate heart rate and blood pressure. These pharmaceutical approaches help ease the burden on the heart but do not physically repair the structural defect.
Modern advancements favor minimally invasive, catheter-based procedures to repair or replace damaged structures. For example, Transcatheter Aortic Valve Replacement (TAVR) allows a new valve to be delivered via a catheter, often inserted through an artery in the leg, to replace a narrowed aortic valve. Similarly, devices resembling small plugs can be deployed via a catheter to close septal defects like a PFO or ASD. Open-heart surgery remains an option for more complex defects, but these less invasive techniques are often preferred due to lower risk and faster recovery times.