Mitral valve prolapse (MVP) and Atrial Fibrillation (AFib) are two distinct but frequently co-occurring heart conditions. MVP is a structural issue where the valve between the heart’s left-sided chambers does not close correctly. AFib is an electrical disorder characterized by a rapid and irregular heart rhythm originating in the upper chambers. Evidence confirms a strong association, showing that the structural problem of MVP can lead to the electrical problem of AFib, particularly when valve dysfunction is severe, creating a pathway where a mechanical defect contributes to a rhythm disturbance.
Defining Mitral Valve Prolapse and Its Types
The heart contains four valves that ensure blood flows in a single direction; the mitral valve separates the left atrium (upper chamber) from the left ventricle (lower chamber). Normally, the mitral valve’s two flaps, or leaflets, close tightly during the heart’s contraction phase to prevent backflow of blood. Mitral valve prolapse occurs when one or both of these leaflets bulge backward into the left atrium during this contraction.
The most common form of MVP involves myxomatous degeneration, where the valve tissue becomes abnormally thickened and floppy. This excessive stretchiness causes the leaflets to lose their firm structure and prolapse.
When the leaflets do not seal properly, blood leaks backward from the ventricle into the atrium, a condition known as mitral regurgitation (MR). The severity of this backflow is a factor in determining the overall impact on heart function. While many cases of MVP are mild, the presence of significant regurgitation is the primary driver for subsequent complications, including heart rhythm issues.
The Confirmed Link Between MVP and AFib
Research confirms that the presence of Mitral Valve Prolapse significantly increases a person’s risk of developing Atrial Fibrillation. This relationship is a progression that depends heavily on the degree of blood backflow across the valve. Patients with MVP who have little to no mitral regurgitation have a low rate of AFib, often comparable to the general population.
However, as the severity of the mitral regurgitation increases, the prevalence of AFib rises sharply. For patients with severe mitral regurgitation due to MVP, the lifetime risk of developing AFib is substantially higher. The volume of blood leaking back into the left atrium is the determining factor in this progression. While MVP is the underlying structural cause, the resulting regurgitation is what drives the electrical instability. The development of new-onset AFib in a person with severe mitral regurgitation often signals that the heart is experiencing significant stress.
How MVP Triggers Electrical Instability
The mechanical stress caused by mitral regurgitation is the primary mechanism that translates the structural problem of MVP into the electrical problem of AFib. When blood leaks backward into the left atrium, it causes the chamber to experience volume and pressure overload. This leads to the left atrium’s progressive enlargement and stretching over time.
This sustained mechanical stretching of the atrial wall initiates a process called atrial remodeling. The constant strain causes normal heart muscle cells to be replaced by fibrous tissue, or scar tissue, throughout the atrial wall. This fibrosis disrupts the coordinated flow of electrical impulses, which normally travel through the atria in an organized wave.
Electrical signals begin to travel at differing velocities through the scarred and stretched tissue, creating disorganized pathways and circuits. This allows the electrical impulses to spiral back on themselves, forming reentrant circuits that fire chaotically. This chaotic firing is the substrate for the erratic, uncoordinated rhythm of Atrial Fibrillation.
Management and Treatment Protocols
Managing a patient with both Mitral Valve Prolapse and Atrial Fibrillation involves a dual approach: treating the rhythm disorder and addressing the underlying valve problem. Diagnosis relies on an echocardiogram to assess the severity of the mitral regurgitation and the size of the left atrium. An electrocardiogram (ECG) or a Holter monitor is used to confirm the presence and pattern of the AFib.
Treatment for Atrial Fibrillation focuses on two main goals: controlling the heart rate or restoring a normal rhythm, and preventing stroke. Medications such as beta-blockers or calcium channel blockers are used to slow the ventricular rate, while antiarrhythmic drugs may be used to convert the rhythm back to normal sinus rhythm. Because AFib raises the risk of blood clot formation and subsequent stroke, anticoagulation therapy (blood thinners) is a necessary part of the management plan for most patients.
Surgical intervention on the mitral valve is often considered when the regurgitation is severe, especially if AFib is newly present. Mitral valve repair is generally preferred over replacement, as it preserves the patient’s own tissue when feasible. Surgical guidelines recommend considering valve intervention for asymptomatic patients with severe regurgitation if new-onset AFib develops. Repairing the valve eliminates the regurgitation and reverses the pressure overload on the left atrium. This can potentially prevent further atrial remodeling, which may resolve the AFib or make it easier to manage.