15.1: Mitral Valve Prolapse I: Introduction

Introduction

The mitral valve, one of the heart's four valves, regulates blood flow. These valves have flaps that open and close to direct blood properly through the heart and body. During each heartbeat, the flaps open for blood to pass through and seal shut to prevent backflow. Specifically, the mitral valve opens to allow blood flow from the heart's upper left chamber to the lower left chamber. It then closes securely as the lower left chamber contracts to pump blood to the body, preventing any backward flow.

Meaning:

Mitral valve prolapse is a heart condition marked by the improper operation of the mitral valve. It occurs when the valve flaps fail to close smoothly and tightly during systole, causing the enlarged leaflets to prolapse back into the left atrium.

Etiology:

Mitral Valve Prolapse is caused by a complex interplay of genetic, structural, developmental, and possibly gender-related factors.

• The exact causes are unclear, but heredity plays a significant role, suggesting a genetic predisposition.
• MVP is often found in families and is commonly associated with inherited connective tissue disorders like Marfan syndrome, Ehlers-Danlos syndrome, and osteogenesis imperfecta. These disorders affect the body's connective tissues, leading to structural abnormalities in the mitral valve.
• The key factors are structural changes in the valve, particularly myxomatous degeneration, where the valve leaflets become thickened and spongy. This excess tissue can cause the leaflets to prolapse into the left atrium during heart contraction. Additionally, alterations in the chordae tendineae, the cords that anchor the valve leaflets to the heart muscle, can contribute to MVP.
• Developmental factors also play a role, as some cases of MVP can be traced back to developmental abnormalities in the fetal stage. As people age, age-related degenerative changes in the valve leaflets might also contribute to the development of MVP.
• Furthermore, there is evidence to suggest a higher prevalence of MVP in women, though the reasons behind this gender disparity are not fully understood.
• Other associated risk factors include conditions like scoliosis, chest wall deformities, and certain muscular dystrophies.

Pathophysiology:

Mitral Valve Prolapse (MVP) pathophysiology encompasses crucial mechanisms that impact the mitral valve's structure and function.

The pathophysiology of Mitral Valve Prolapse involves key mechanisms affecting the mitral valve's structure and function. Abnormal thickening of the valve leaflets due to myxomatous degeneration and the resultant increase in size and flexibility of the leaflets cause them to prolapse into the left atrium during systole. It disrupts normal valve closure. Alterations in the chordae tendineae anchor the valve leaflets to the heart's papillary muscles, further impair closure, and increase prolapse likelihood. Mitral regurgitation, where blood rushes back into the left atrium during systole, can lead to volume overload in the left atrium. Significant mitral regurgitation may cause enlargement or hypertrophy of the left atrium and left ventricle, potentially resulting in complications like atrial fibrillation, pulmonary hypertension, and heart failure.