The evolution of mitral valve prolapse: insights from the Framingham Heart Study

Arrhythmic Mitral Valve Prolapse Syndrome and Ventricular Arrhythmias: A Comprehensive Review and the Role of Catheter Ablation

Mitral valve prolapse (MVP) affects 2-3% of the general population, and despite its benign prognosis overall, it is associated with sudden death in a small subset of patients. The term "arrhythmic MVP syndrome" (AMVPS) refers to the presence of frequent or complex ventricular arrhythmias, commonly reported in female patients with a stereotypical phenotype including bileaflet myxomatous disease, ECG repolarisation abnormalities in inferior leads, mitral annular disjunction, and significant fibrosis in the inferolateral LV and papillary muscles. Modern imaging technologies have led to the identification of new risk factors that have been implemented in recent risk stratification guidelines; however, screening for patients with MVP who are at risk of sudden cardiac death (SCD) remains challenging. In addition, there is a limited amount of data on the outcomes of different treatment approaches in AMVP and no specific indication for targeted or disease-modifying therapies within current guidelines. Potential arrhythmic substrates in patients with AMVP syndrome have been the subject of interest in previous studies, with areas consisting of fibrosis at the papillary muscle level and the Purkinje system. Premature ventricular contractions (PVCs) originating from these areas have been shown to play an important role as triggers for ventricular fibrillation and SCD in patients with AMVP. Catheter ablation has emerged as a potential treatment modality in patients with MVP and ventricular arrhythmias (VAs), targeting arrhythmic substrates and triggering PVC foci. The aim of this review is to explore the role of catheter ablation in treating patients with AMVP.

Imaging for the assessment of the arrhythmogenic potential of mitral valve prolapse

Mitral valve prolapse (MVP) is the most common valve disease in the western world and recently emerged as a possible substrate for sudden cardiac death (SCD). It is estimated an annual risk of sudden cardiac death of 0.2 to 1.9% mostly caused by complex ventricular arrhythmias (VA). Several mechanisms have been recognized as potentially responsible for arrhythmia onset in MVP, resulting from the combination of morpho-functional abnormality of the mitral valve, structural substrates (regional myocardial hypertrophy, fibrosis, Purkinje fibers activity, inflammation), and mechanical stretch. Echocardiography plays a central role in MVP diagnosis and assessment of severity of regurgitation. Several abnormalities detectable by echocardiography can be prognostic for the occurrence of VA, from morphological alteration including leaflet redundancy and thickness, mitral annular dilatation, and mitral annulus disjunction (MAD), to motion abnormalities detectable with "Pickelhaube" sign. Additionally, speckle-tracking echocardiography may identify MVP patients at higher risk for VA by detection of increased mechanical dispersion. On the other hand, cardiac magnetic resonance (CMR) has the capability to provide a comprehensive risk stratification combining the identification of morphological and motion alteration with the detection of myocardial replacement and interstitial fibrosis, making CMR an ideal method for arrhythmia risk stratification in patients with MVP. Finally, recent studies have suggested a potential role in risk stratification of new techniques such as hybrid PET-MR and late contrast enhancement CT. The purpose of this review is to provide an overview of the mitral valve prolapse syndrome with a focus on the role of imaging in arrhythmic risk stratification. CLINICAL RELEVANCE STATEMENT: Mitral valve prolapse is the most frequent valve condition potentially associated with arrhythmias. Imaging has a central role in the identification of anatomical, functional, mechanical, and structural alterations potentially associated with a higher risk of developing complex ventricular arrhythmia and sudden cardiac death. KEY POINTS: • Mitral valve prolapse is a common valve disease potentially associated with complex ventricular arrhythmia and sudden cardiac death. • The mechanism of arrhythmogenesis in mitral valve prolapse is complex and multifactorial, due to the interplay among multiple conditions including valve morphological alteration, mechanical stretch, myocardial structure remodeling with fibrosis, and inflammation. • Cardiac imaging, especially echocardiography and cardiac magnetic resonance, is crucial in the identification of several features associated with the potential risk of serious cardiac events. In particular, cardiac magnetic resonance has the advantage of being able to detect myocardial fibrosis which is currently the strongest prognosticator.

Transcatheter mitral valve repair for primary mitral regurgitation

The landscape of transcatheter mitral valve repair devices continues to expand, with many technologies undergoing investigation in patients with primary mitral regurgitation (MR). Transcatheter edge-to-edge repair (TEER) of the mitral valve is currently approved for management of patients with severe primary MR who are deemed to be high risk surgical candidates. The current review will focus on an integrative clinical and echocardiographic approach to guide patient selection, intra-procedural imaging guidance, and post procedural follow up in patients undergoing TEER. This review will also highlight future directions in transcatheter repair techniques of the mitral valve.

Mitral Regurgitation in Patients Undergoing Noncardiac Surgery

Mitral regurgitation (MR) is one of the most frequently encountered types of valvular heart disease in the United States. Patients with significant MR (moderate-to-severe or severe) undergoing noncardiac surgery have an increased risk of perioperative cardiovascular complications. MR can arise from a diverse array of causes that fall into 2 broad categories: primary (diseases intrinsic to the valvular apparatus) and secondary (diseases that disrupt normal valve function via effects on the left ventricle or mitral annulus). This article highlights key guideline updates from the American College of Cardiologists (ACC) and the American Heart Association (AHA) that inform decision-making for the anesthesiologist caring for a patient with MR undergoing noncardiac surgery. The pathophysiology and natural history of acute and chronic MR, staging of chronic primary and secondary MR, and considerations for timing of valvular corrective surgery are reviewed. These topics are then applied to a discussion of anesthetic management, including preoperative risk evaluation, anesthetic selection, hemodynamic goals, and intraoperative monitoring of the noncardiac surgical patient with MR.

A Population-Based Study of Healthcare Resource Utilization in Patients with Mitral Valve Prolapse

This study investigated differences in the utilization of healthcare services between subjects with mitral valve prolapse (MVP) and comparison subjects using data from Taiwan's National Health Insurance population-based database, 138,493 patients with MVP (study group) and 138,493 matched patients without MVP (comparison group). We calculated the utilization of healthcare services in the year 2016 for each study sample. Patients with MVP had more outpatient cardiological services during the year (5.3 vs. 0.7, p < 0.001) and higher outpatient cardiology costs (US$226.0 vs. US$30.8, p < 0.001) than patients without MVP. As expected, patients with MVP had a longer inpatient stay (0.5 vs. 0.1, p < 0.001) and higher inpatients costs (US$158.0 vs. US$22.9, p < 0.001) than patients without MVP for cardiology services. Furthermore, patients with MVP also had more outpatient non-cardiology services (20.8 vs. 16.5, p < 0.001) and associated costs (US$708.3 vs. US$518.7, p < 0.001) than patients without MVP in the year 2016. Multiple regression analysis indicated that patients with MVP had higher total costs for all healthcare services than patients without MVP after adjusting for the urbanization level, monthly income, and geographic region. This study demonstrated that healthcare utilization by patients with MVP is substantially higher than comparison patients. Future studies are encouraged to explore MVP treatment with less expensive modalities while maintaining care quality and without jeopardizing patient outcomes.

Cardiac magnetic resonance in patients with mitral valve prolapse: Focus on late gadolinium enhancement and T1 mapping

OBJECTIVES

To evaluate the incidence of late-gadolinium-enhancement (LGE) in mitral valve prolapse (MVP) (in the absence of other heart/valvular diseases), and its association with the degree of mitral regurgitation (MR) and/or with complex ventricular arrhythmia (ComVA), and to analyse the role of T1 mapping in the evaluation of MVP patients.

METHODS

We included all consecutive patients with MVP who underwent during 2015-2016 a comprehensive cardiac magnetic resonance (CMR) examination at 1.5 T. We evaluated the association of LGE with the MR fraction and the presence of ComVA. We compared myocardial T1-native and post-contrast times and extracellular volume (ECV)-values between MVP patients, both with and without LGE, and the control group.

RESULTS

Thirty-four patients with MVP were selected (56 ± 14 years old, 59% male). All patients had MR; LGE and ComVA were present in 15 (44%) and 11 (34%) patients, respectively. Significant associations of LGE with both MR severity and ComVA were not found (p=0.72 and 0.79, respectively). T1 mapping confirmed the presence of LGE in all cases. In one patient a thin signal alteration resulted in more evident T1 mapping than LGE. Patients with MVP had higher native T1-values, lower post-contrast T1-values and increased ECV-values compared with controls (p=0.01, 0.01 and 0.00, respectively).

CONCLUSION

Focal fibrosis with LGE was found in about half the MVP patients and it was independent of the degree of the valve dysfunction and the presence of ComVA. T1 mapping allows diffuse myocardial wall alterations to be identified, but no significant associations between the MR severity and ComVA and T1/ECV values were found.

KEY POINTS

• MVP is a common valvulopathy affecting 2-3% of the general population. • MVP has been associated with an increased risk of arrhythmic complications and sudden cardiac death. • CMR is a non-invasive imaging method that provides a precise and more accurate assessment of patients with MVP.