Mitral Valve Prolapse, Ventricular Arrhythmias, and Sudden Death

The Mitral Annular Disjunction of Mitral Valve Prolapse: Presentation and Outcome

OBJECTIVES

The aim of this study was to assess in patients with mitral valve prolapse (MVP) mitral annular disjunction (MAD) prevalence, phenotypic characteristics, and long-term outcomes (clinical arrhythmic events and excess mortality).

BACKGROUND

Clinical knowledge regarding MAD of MVP remains limited and controversial, and its potential link with untoward outcomes is unsubstantiated.

METHODS

A cohort of 595 (278 women, mean age 61 ± 16 years) consecutive patients with isolated MVP, with comprehensive clinical, rhythmic, Doppler echocardiographic, and consistent MAD assessment, were examined. MAD prevalence, associated MVP phenotypes, and outcomes (survival, clinical arrhythmic events) starting at diagnostic echocardiography were analyzed. To balance important baseline differences, propensity scoring matching was conducted among patients with and those without MAD.

RESULTS

The presence of MAD was common (n = 186 [31%]) in patients with MVP, generally in younger patients, and was not random but was independently associated with severe myxomatous disease involving bileaflet MVP and marked leaflet redundancy (both P ≤ 0.0002). The presence of MAD was also independently associated with a larger left ventricle (P = 0.005). Age-matched cohort survival after MVP diagnosis was not worse with MAD (10-year survival 93% ± 2% for patients without MAD and 97% ± 1% for those with MAD; P = 0.40), even adjusted comprehensively for MVP characteristics (P = 0.80) and accounting for time-dependent mitral surgery (P = 0.60). During follow-up, 170 patients had clinical arrhythmic events (ventricular tachycardia, n = 159; arrhythmia ablation, n = 14; cardioverter-defibrillator implantation, n = 14; sudden cardiac death, n = 3). MAD was independently associated with higher risk for arrhythmic events (adjusted HR: 2.60; 95% CI: 1.87-3.62; P < 0.0001). The link between MAD and arrhythmic events persisted with time-dependent mitral surgery (adjusted HR: 2.54; 95% CI: 1.84-3.50; P < 0.0001), was strong under medical management (adjusted HR: 3.21; 95% CI: 2.03-5.06; P < 0.0001) but was weaker after mitral surgery (adjusted HR: 2.07; 95% CI: 1.24-3.43; P = 0.005).

CONCLUSIONS

This large cohort with MVP comprehensively characterized shows that MAD is frequent at MVP diagnosis and is strongly linked to advanced myxomatous degeneration. The presence of MAD was independently associated with long-term excess incidence of clinical arrhythmic events. However, within the first 10 years post-diagnosis, MAD was not linked to excess mortality, and although reassurance should be provided from the survival point of view, careful monitoring for arrhythmias is in order for MAD.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart

Background

Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear.

Objective

The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology.

Methods

In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models.

Results

Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01).

Conclusion

Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.

Feature tracking myocardial strain analysis in patients with bileaflet mitral valve prolapse: relationship with LGE and arrhythmias

OBJECTIVES

Anatomical substrate and mechanical trigger co-act in arrhythmia's onset in patients with bileaflet mitral valve prolapse (bMVP). Feature tracking (FT) may improve risk stratification provided by cardiac magnetic resonance (CMR). The aim was to investigate differences in CMR and FT parameters in bMVP patients with and without complex arrhythmias (cVA and no-cVA).

METHODS

In this retrospective study, 52 patients with bMVP underwent 1.5 T CMR and were classified either as no-cVA (n = 32; 12 males; 49.6 ± 17.4 years) or cVA (n = 20; 3 males; 44.7 ± 11.2 years), the latter group including 6 patients (1 male; 45.7 ± 12.7 years) with sustained ventricular tachycardia or ventricular fibrillation (SVT-FV). Twenty-four healthy volunteers (11 males, 36.2 ± 12.5 years) served as control. Curling, prolapse distance, mitral annulus disjunction (MAD), and late gadolinium enhancement (LGE) were recorded and CMR-FT analysis performed. Statistical analysis included non-parametric tests and binary logistic regression.

RESULTS

LGE and MAD distance were associated with cVA with an odds ratio (OR) of 8.51 for LGE (95% CI 1.76, 41.28; p = 0.008) and of 1.25 for MAD (95% CI 1.02, 1.54; p = 0.03). GLS 2D (- 11.65 ± 6.58 vs - 16.55 ± 5.09 1/s; p = 0.04), PSSR longitudinal 2D (0.04 ± 1.62 1/s vs - 1.06 ± 0.35 1/s; p = 0.0001), and PSSR radial 3D (3.95 ± 1.97 1/s vs 2.64 ± 1.03 1/s; p = 0.0001) were different for SVT-VF versus the others. PDSR circumferential 2D (1.10 ± 0.54 vs. 0.84 ± 0.34 1/s; p = 0.04) and 3D (0.94 ± 0.42 vs. 0.69 ± 0.17 1/s; p = 0.04) differed between patients with and without papillary muscle LGE.

CONCLUSIONS

CMR-FT allowed identifying subtle myocardial deformation abnormalities in bMVP patients at risk of SVT-VF. LGE and MAD distance were associated with cVA.

KEY POINTS

• CMR-FT allows identifying several subtle myocardial deformation abnormalities in bMVP patients, especially those involving the papillary muscle. • CMR-FT allows identifying subtle myocardial deformation abnormalities in bMVP patients at risk of SVT and VF. • In patients with bMVP, the stronger predictor of cVA is LGE (OR = 8.51; 95% CI 1.76, 41.28; p = 0.008), followed by MAD distance (OR = 1.25; 95% CI 1.02, 1.54; p = 0.03).

Athletes with valvular heart disease and competitive sports: a position statement of the Sport Cardiology Section of the European Association of Preventive Cardiology

This article provides an overview of the recommendations from the Sports Cardiology section of the European Association of Preventive Cardiology on sports participation in individuals with valvular heart disease (VHD). The aim of these recommendations is to encourage regular physical activity including sports participation, with reasonable precaution to ensure a high level of safety for all affected individuals. Valvular heart disease is usually an age-related degenerative process, predominantly affecting individuals in their fifth decade and onwards. However, there is an increasing group of younger individuals with valvular defects. The diagnosis of cardiac disorders during routine cardiac examination often raises questions about on-going participation in competitive sport with a high dynamic or static component and the level of permissible physical effort during recreational exercise. Although the natural history of several valvular diseases has been reported in the general population, little is known about the potential influence of chronic intensive physical activity on valve function, left ventricular remodelling pulmonary artery pressure, and risk of arrhythmia. Due to the sparsity of data on the effects of exercise on VHD, the present document is largely based on clinical experience and expert opinion.

Mitral annular disjunction in patients with severe aortic stenosis: Extent and reproducibility of measurements with computed tomography

•

Mitral annulus disjunction (MAD) is frequent in patients with severe aortic stenosis.

•

Computed tomography enables a highly reproducible assessment of MAD.

•

MAD patients significantly more often have mitral valve prolapse.

Objectives

To determine with CT the prevalence and extent of mitral annular disjunction (MAD) in patients undergoing transcatheter aortic valve replacement (TAVR) and its association with mitral valve disease and arrhythmia.

Methods

We retrospectively evaluated 408 patients (median age, 82 years; 186 females) with severe aortic stenosis undergoing ECG-gated cardiac CT with end-systolic data acquisition. Baseline and follow-up data were collected in the context of a national registry. Two blinded, independent observers evaluated the presence of MAD on multi-planar reformations. Maximum MAD distance (left atrial wall-mitral leaflet junction to left ventricular myocardium) and circumferential extent of MAD were assessed on CT using dedicated post-processing software. Associated mitral valve disease was determined with echocardiography.

Results

7.8 % (32/408) of patients with severe aortic stenosis had MAD. The maximum MAD was 3.5 mm (interquartile range: 3.0–4.0 mm). The circumferential extent of MAD comprised 34 ± 15 % of the posterior and 26 ± 12 % of the entire mitral annulus. Intra- and interobserver agreement for the detection of MAD on CT were excellent (kappa: 0.90 ± 0.02 and 0.92 ± 0.02). Mitral regurgitation (p = 1.00) and severe mitral annular calcification (p = 0.29) were similarly prevalent in MAD and non-MAD patients. Significantly more patients with MAD (6/32; 19 %) had mitral valve prolapse compared to those without (6/376; 2 %; p < 0.001). MAD was not associated with arrhythmia before and after TAVR (p > 0.05).

Conclusions

Using CT, MAD was found in 7.8 % of patients with severe aortic stenosis, with a higher prevalence in patients with mitral valve prolapse. We found no association of MAD with arrhythmia before or after TAVR.

Exercise Participation for Patients with Valvular Heart Disease: a Review of the Current Guidelines

PURPOSE OF REVIEW

Valvular heart disease affects many individuals who aspire to partake in competitive or recreational sports. This manuscript reviews the most recent European and American guidelines related to exercise and sport participation in individuals with valvular heart disease (VHD) and identifies areas not addressed by these guidelines.

RECENT FINDINGS

Exercise recommendations for individuals with VHD have been presented since at least 1984. There is limited data on the impact of intensive physical activity on the progression and outcomes of VHD. Therefore, current recommendations are based on consensus opinion. Most recent consensus guidelines address exercise participation in young and active older individuals. Exercise guidelines for patients with VHD have become progressively less restrictive to allow exercise participation for many VHD patients. These more progressive recommendations should be included in clinical decision-making when evaluating physical activity levels for athletes and active adults with VHD.

Replacement Myocardial Fibrosis in Patients With Mitral Valve Prolapse: Relation to Mitral Regurgitation, Ventricular Remodeling, and Arrhythmia

BACKGROUND

Mitral valve prolapse (MVP) is a frequent disease that can be complicated by mitral regurgitation (MR), heart failure, arterial embolism, rhythm disorders, and death. Left ventricular (LV) replacement myocardial fibrosis, a marker of maladaptive remodeling, has been described in patients with MVP, but the implications of this finding remain scarcely explored. We aimed at assessing the prevalence, pathophysiological and prognostic significance of LV replacement myocardial fibrosis through late gadolinium enhancement (LGE) by cardiac magnetic resonance in patients with MVP.

METHODS

Four hundred patients (53±15 years of age, 55% male) with MVP (trace to severe MR by echocardiography) from 2 centers, who underwent a comprehensive echocardiography and LGE cardiac magnetic resonance, were included. Correlates of replacement myocardial fibrosis (LGE+), influence of MR degree, and ventricular arrhythmia were assessed. The primary outcome was a composite of cardiovascular events (cardiac death, heart failure, new-onset atrial fibrillation, arterial embolism, and life-threatening ventricular arrhythmia).

RESULTS

Replacement myocardial fibrosis (LGE+) was observed in 110 patients (28%; 91 with myocardial wall including 71 with basal inferolateral wall, 29 with papillary muscle). LGE+ prevalence was 13% in trace-mild MR, 28% in moderate MR, and 37% in severe MR, and was associated with specific features of mitral valve apparatus, more dilated LV and more frequent ventricular arrhythmias (45% versus 26%, P<0.0001). In trace-mild MR, despite the absence of significant volume overload, abnormal LV dilatation was observed in 16% of patients and ventricular arrhythmia in 25%. Correlates of LGE+ in multivariable analysis were LV mass (odds ratio, 1.01 [95% CI, 1.002-1.017], P=0.009) and moderate-severe MR (odds ratio, 2.28 [95% CI, 1.21-4.31], P=0.011). LGE+ was associated with worse 4-year cardiovascular event-free survival (49.6±11.7 in LGE+ versus 73.3±6.5% in LGE-, P<0.0001). In a stepwise multivariable Cox model, MR volume and LGE+ (hazard ratio, 2.6 [1.4-4.9], P=0.002) were associated with poor outcome.

CONCLUSIONS

LV replacement myocardial fibrosis is frequent in patients with MVP; is associated with mitral valve apparatus alteration, more dilated LV, MR grade, and ventricular arrhythmia; and is independently associated with cardiovascular events. These findings suggest an MVP-related myocardial disease. Last, cardiac magnetic resonance provides additional information to echocardiography in MVP.

Arrhythmic Mitral Valve Prolapse: Introducing an Era of Multimodality Imaging-Based Diagnosis and Risk Stratification

Mitral valve prolapse is a common cardiac condition, with an estimated prevalence between 1% and 3%. Most patients have a benign course, but ever since its initial description mitral valve prolapse has been associated to sudden cardiac death. Although the causal relationship between mitral valve prolapse and sudden cardiac death has never been clearly demonstrated, different factors have been implicated in arrhythmogenesis in patients with mitral valve prolapse. In this work, we offer a comprehensive overview of the etiology and the genetic background, epidemiology, pathophysiology, and we focus on the state-of-the-art imaging-based diagnosis of mitral valve prolapse. Going beyond the classical, well-described clinical factors, such as young age, female gender and auscultatory findings, we investigate multimodality imaging features, such as alterations of anatomy and function of the mitral valve and its leaflets, the structural and contractile anomalies of the myocardium, all of which have been associated to sudden cardiac death.

Characterization of Degenerative Mitral Valve Disease: Differences between Fibroelastic Deficiency and Barlow's Disease

Degenerative mitral valve disease causing mitral valve prolapse is the most common cause of primary mitral regurgitation, with two distinct phenotypes generally recognized with some major differences, i.e., fibroelastic deficiency (FED) and Barlow’s disease. The aim of this review was to describe the main histological, clinical and echocardiographic features of patients with FED and Barlow’s disease, highlighting the differences in diagnosis, risk stratification and patient management, but also the still significant gaps in understanding the exact pathophysiology of these two phenotypes.

Cardiac Imaging for Risk Assessment of Malignant Ventricular Arrhythmias in Patients With Mitral Valve Prolapse

Recent studies have described the occurrence of complex ventricular arrhythmias and sudden cardiac death among patients with mitral valve prolapse (MVP). The reported incidence rate of sudden cardiac death or ventricular tachycardia is about 1–1.5% among patients with MVP. Various imaging markers have been associated with this increased risk, including mitral annular disjunction, replacement fibrosis by late gadolinium enhancement, and mechanical dispersion. In this review, we briefly discuss how multimodality cardiac imaging can be applied to identify MVP patients with high risk of sudden cardiac death and complex ventricular arrhythmias.

The Female Athlete's Heart: Overview and Management of Cardiovascular Diseases

The number of female athletes taking part in elite and amateur sport is ever increasing. In contrast with male athletes, few studies have focused on cardiovascular adaptations to exercise in women, the effects of lifelong exercise on heart muscle and electrical tissue, the risk of exerciserelated sudden cardiac death and the management of cardiovascular disease. Women have a lower prevalence of large QRS complexes, repolarisation changes including inferior and lateral T-wave inversion, and cardiac dimensions exceeding predicted limits compared with men. The risk of exercise-related sudden cardiac death is significantly lower in women than men. Also, women who have engaged in lifelong exercise do not have a higher prevalence of AF, coronary artery calcification or myocardial fibrosis than their sedentary counterparts. Apart from providing an overview of the existing literature relating to cardiac adaptations, this review explores possible reasons for the sex differences and focuses on the management of cardiovascular disorders that affect female athletes.

Aborted sudden cardiac death due to ventricular fibrillation in a female patient with mitral valve prolapse

Background

Mitral valve prolapse is the most frequent valvular defect associated with a wide range of electro-hemodynamic abnormalities, leading to heart failure, arrhythmias and sudden cardiac death. Mitral valve prolapse, first described from Barlow in the 1960s, is defined as displacement of mitral leaflet tissue into the left atrium past the mitral annular plane during systole. The correlation between mitral valve prolapse and sudden cardiac death has been investigated and clarified by various studies in recent years. However, identifying patients at risk and applying measures to prevent those from sudden cardiac death is challenging.

Case presentation

We report on a 61-year-old female patient who had undergone an aborted sudden cardiac death. An arrythmogenic mitral valve prolapse was diagnosed. In addition, electrocardiographically and morphologically risk markers for sudden cardiac death were found in this case. We performed an ICD implantation as secondary prophylaxis and intended to reconstruct the mitral valve.

Conclusion

This article examines the association of mitral valve prolapse with sudden cardiac death, the underlying pathophysiological mechanisms and the strategies leading to identify the risk group.

Myxomatous Mitral Valve Disease with Mitral Valve Prolapse and Mitral Annular Disjunction: Clinical and Functional Significance of the Coincidence

The morphological changes that occur in myxomatous mitral valve disease (MMVD) involve various components, ultimately leading to the impairment of mitral valve (MV) function. In this context, intrinsic mitral annular abnormalities are increasingly recognized, such as a mitral annular disjunction (MAD), a specific anatomical abnormality whereby there is a distinct separation between the mitral annulus and the left atrial wall and the basal portion of the posterolateral left ventricular myocardium. In recent years, several studies have suggested that MAD contributes to myxomatous degeneration of the mitral leaflets, and there is growing evidence that MAD is associated with ventricular arrhythmias and sudden cardiac death. In this review, the morphological characteristics of MAD and imaging tools for diagnosis will be described, and the clinical and functional aspects of the coincidence of MAD and myxomatous MVP will be discussed.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

Systematic quantification of histologic ventricular fibrosis in isolated mitral valve prolapse and sudden cardiac death

BACKGROUND

Cardiac fibrosis in mitral valve prolapse (MVP) is implicated in the development of sudden cardiac death (SCD); however, the pattern remains poorly characterized.

OBJECTIVE

The purpose of this study was to systematically quantify left and right ventricular fibrosis in individuals with isolated MVP and SCD (iMVP-SCD), whereby other potential causes of death are excluded, compared to a control cohort.

METHODS

Individuals with iMVP-SCD were identified from the Victorian Institute of Forensic Medicine, Australia, and matched for age, sex, and body mass index to control cases with noncardiac death. Cardiac tissue sections were analyzed to determine collagen deposition in the left ventricular free wall (anterior, lateral, and posterior portions), interventricular septum, and right ventricle. Within the iMVP-SCD cases, the endocardial-to-epicardial distribution of fibrosis within the left ventricle was specifically characterized.

RESULTS

Seventeen cases with iMVP-SCD were matched 1:1 with 17 controls, yielding 149 samples and 1788 histologic regions. The iMVP-SCD group had increased left ventricular (anterior, lateral, and posterior; all P <.001) and interventricular septum fibrosis (P <.001), but similar amounts of right ventricular fibrosis (P = .62) compared to controls. In iMVP-SCD, left ventricular fibrosis was significantly higher in the lateral and posterior walls compared to the anterior wall and interventricular septum (all P <.001). Within the lateral and posterior walls, iMVP-SCD cases had a significant endocardial-to-epicardial gradient of cardiac fibrosis (P <.01) similar to other known conditions that cause cardiac remodeling.

CONCLUSION

Our study indicates that nonuniform left ventricular remodeling with both localized and generalized left ventricular fibrosis is important in the pathogenesis of SCD in individuals with MVP.

Fokus: Mitral Annulus Disjunction Arrhythmic Syndrome

Als „Mitral annular Disjunction“ (MAD) bezeichnet man eine pathologische, umschriebene, bindegewebige Dehiszenz zwischen dem kompakten Myokard des linken Ventrikels und dem Mitralklappenanulus. Das Bindegewebe ersetzt anulusnah das Myokard und strahlt in unregelmäßiger Form in die benachbarte Muskulatur des linken Ventrikels ein. Die MAD tritt oft in Verbindung mit einem Mitralklappenprolaps (MVP) auf. Die inhomogene Fibrosierung des klappennahen Myokards sowie eingelagerte und versprengte Purkinje-Fasern bilden ein arrhythmogenes Substrat. Die MAD wird deshalb gehäuft bei Patienten mit ventrikulären Herzrhythmusstörungen bzw. bei plötzlichem Herztod mit und ohne MVP gefunden. Die Diagnose wird mittels Echokardiografie oder kardialer Magnetresonanztomografie bzw. Computertomografie gestellt. Da die prognostische Bedeutung der MAD unklar ist, gibt es bisher keine Therapieempfehlung.

[Mitral prolapse and sudden death. A case report]

The association between the mitral valve prolapse and the sudden Cardiac Death remains controversial, the high prevalence of this valvulopathy contrasting with the low incidence of sudden death in this population. We report the case of a 54-year-old woman admitted for a sudden cardiac death, revealing a bi-prolapse with low-grade leakage, leading to the implantation of a subcutaneous automatic defibrillator. Combined echocardiography and cardiac MRI can identify the mitral annular disjunction, the rolling motion of the posterior face of the mitral annulus towards the myocardium, and the myocardial fibrosis of the inferolateral wall induced by streching forces of the sub valvular apparatus, that may lead to ventricular arrhythmias. More than the conventional clinical parameters (young woman, ventricular premature beats with a right bundle branch block morphology, mitral bi-prolapse), mitral annular disjunction and myocardial fibrosis are to be considered as powerful markers of the rhythmic risk of mitral prolapse and must be systematically sought and integrated into the prognostic evaluation of these patients. In the absence of randomised trials, therapeutic management is difficult especially in primary prevention, and needs Heart Team advice.

Resolving the Disproportionate Left Ventricular Enlargement in Mitral Valve Prolapse Due to Barlow Disease: Insights From Cardiovascular Magnetic Resonance

OBJECTIVES

This study hypothesized that left ventricular (LV) enlargement in Barlow disease can be explained by accounting for the total volume load that consists of transvalvular mitral regurgitation (MR) and the prolapse volume.

BACKGROUND

Barlow disease is characterized by long prolapsing mitral leaflets that can harbor a significant amount of blood-the prolapse volume-at end-systole. The LV in Barlow disease can be disproportionately enlarged relative to MR severity, leading to speculation of Barlow cardiomyopathy.

METHODS

Cardiac magnetic resonance (CMR) was used to compare MR, prolapse volume, and heart chambers remodeling in patients with Barlow disease (bileaflet prolapse [BLP]) and in single leaflet prolapse (SLP).

RESULTS

A total of 157 patients (81 with BLP, 76 with SLP) were included. Patients with SLP were older and more had hypertension. Patients with BLP had more heart failure. Indexed LV end-diastolic volume was larger in BLP despite similar transvalvular MR. However, the prolapse volume was larger in BLP, which led to larger total volume load compared with SLP. Increasing tertiles of prolapse volume and MR both led to an incremental increase in LV end-diastolic volume in BLP. Using the total volume load improved the correlation with indexed LV end-diastolic volume in the BLP group, which closely matched that of SLP. A multivariable model that incorporated the prolapse volume explained left heart chamber enlargement better than a MR-based model, independent of prolapse category.

CONCLUSIONS

The prolapse volume is part of the total volume load exerted on the LV during the cardiac cycle and could help explain the disproportionate LV enlargement relative to MR severity noted in Barlow disease.

Parameters associated with ventricular arrhythmias in mitral valve prolapse with significant regurgitation

OBJECTIVE

Mitral valve prolapse (MVP) has been associated with ventricular arrhythmias (VA), but little is known about VA in patients with significant primary mitral regurgitation (MR). Our aim was to describe the prevalence of symptomatic VA in patients with MVP (fibro-elastic deficiency or Barlow's disease) referred for mitral valve (MV) surgery because of moderate-to-severe MR, and to identify clinical, electrocardiographic, standard and advanced echocardiographic parameters associated with VA.

METHODS

610 consecutive patients (64±12 years, 36% female) were included. Symptomatic VA was defined as symptomatic and frequent premature ventricular contractions (PVC, Lown grade ≥2), non-sustained or sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) without ischaemic aetiology.

RESULTS

A total of 67 (11%) patients showed symptomatic VA, of which 3 (4%) had VF, 3 (4%) sustained VT, 27 (40%) non-sustained VT and 34 (51%) frequent PVCs. Patients with VA were significantly younger, more often female and showed T-wave inversions; furthermore, they showed significant MV morphofunctional abnormalities, such as mitral annular disjunction (39% vs 20%, p<0.001), and dilatation (annular diameter 37±5 mm vs 33±6 mm, p<0.001), lower global longitudinal strain (GLS 20.9±3.1% vs 22.0±3.6%, p=0.032) and prolonged mechanical dispersion (45±12 ms vs 38±14 ms, p=0.003) as compared with patients without VA. Female sex, increased MV annular diameter, lower GLS and prolonged mechanical dispersion were identified as independent associates of symptomatic VA.

CONCLUSION

In patients with MVP with moderate-to-severe MR, symptomatic VA are relatively frequent and associated with significant MV annular abnormalities, subtle left ventricular function impairment and heterogeneous contraction. Assessment of these parameters might help decision-making over further diagnostic analyses and improve risk-stratification.

Arrhythmia insensitive rapid cardiac T1 mapping: comparison to modified look locker inversion recovery T1 mapping in mitral valve prolapse patients

We compare a saturation recovery arrhythmia insensitive rapid (AIR) T1 mapping technique which is less sensitive to heart rate and requires shorter breath-holds to modified Look-Locker inversion recovery (MOLLI) T1 mapping in patients with mitral valve prolapse. 55 patients underwent AIR and MOLLI at 1.5 T. AIR and MOLLI-derived blood and myocardial T1 values and extracellular volume (ECV) were measured by two independent readers. T1 values and ECV from both techniques and inter-reader agreement were compared with Lin's concordance correlation coefficient (LCC) and reduced major axis regression. T1 values were consistently overestimated for AIR compared to MOLLI and vice versa for ECV. In the mitral valve prolapse population, mean native and post contrast myocardial T1 value for MOLLI were 1000 ± 40 ms and 411.9 ± 44.2 ms respectively and 1090.6 ± 58.7 ms and 488.2 ± 45.7 ms for AIR. Mean native and post contrast blood T1 values for MOLLI were 1566.6 ± 72.3 ms and 276.6 ± 34.1 ms respectively versus 1657.2 ± 180.9 ms and 294.9 ± 35.6 ms for AIR. AIR underestimated ECV relative to MOLLI (23.5 ± 0.4% vs 27.7 ± 0.4%). We found excellent inter-reader agreement (LCC all > 0.94, p < 0.0001) for both AIR and MOLLI techniques as well as intra-reader reliability (LCC all > 0.97, p < 0.0001). AIR can be performed in patients with mitral valve prolapse with excellent inter and intra-reader agreement, with higher T1 values compared to MOLLI, in line with other saturation recovery techniques. A consistent T1 mapping technique should be used when performing serial imaging.

Long-term outcomes of ablation for ventricular arrhythmias in mitral valve prolapse

PURPOSE

Prior studies reporting efficacy of radiofrequency catheter ablation for complex ventricular ectopy in mitral valve prolapse (MVP) are limited by selective inclusion of bileaflet MVP, papillary muscle only ablation, or short-term follow-up. We sought to evaluate the long-term incidence of hemodynamically significant ventricular tachycardia (VT) or fibrillation (VF) in patients with MVP after initial ablation.

METHODS

We studied consecutive patients with MVP undergoing ablation for complex ventricular ectopy between 2013 and 2017 at our institution. Of 580 patients with MVP, we included 15 (2.6%, 10 women; mean age 50 ± 14 years, 53% bileaflet) with complex ventricular ectopy treated with initial ablation.

RESULTS

Over a median follow-up of 3406 (1875-6551) days or 9 years, 5 of 15 (33%) patients developed hemodynamically significant VT/VF after their initial ablation and underwent placement of an implantable cardioverter defibrillator (ICD). Three of 5 also underwent repeat ablations. Sustained VT was inducible prior to index ablation in all 5 who developed VT/VF, compared to none of the 10 patients who did not develop VT/VF after index ablation (p = 0.002). Complex ventricular ectopy at index ablation was multifocal in all 5 patients who underwent repeat intervention versus 4 of 10 patients (40%) who did not (p = 0.04). All 3 patients with subsequent VT/VF who underwent repeat ablation had a new clinically dominant focus of ventricular arrhythmia and 3 of the patients with ICD had appropriate VT/VF therapies.

CONCLUSIONS

In the long term, a subset of MVP patients treated with ablation for ventricular arrhythmias, all with multifocal ectopy on initial EP study, develop hemodynamically significant VT/VF. Our findings suggest the progressive nature of ventricular arrhythmias in patients with MVP and multifocal ectopy.

Ventricular arrhythmias and risk stratification of cardiac sudden death in athletes

Sudden cardiac death (SCD) of young athletes is an unexpected and tragic event that could occur during sport activities and is frequently related to ventricular arrhythmias. Identifying athletes at risk of SCD remains a major challenge. While specific characteristics of premature ventricular contractions are considered common and benign, other "uncommon" features should require more accurate investigations, in order to determine eligibility for competitive sports. The most common type of idiopathic premature ventricular contractions originates from ventricular outflow tract and is characterized by an ECG pattern with left bundle branch block and inferior QRS axis (infundibular pattern). Another pattern associated with a good prognosis is the "fascicular" morphology, characterized by a typical right bundle branch block, superior QRS axis morphology and QRS duration <130 ms. Conversely, other morphological features (such as left bundle branch block /intermediate or superior axis or right bundle branch block/intermediate or superior axis and wide QRS) correlate to an underlying substrate. In risk stratification setting, cardiac magnetic resonance plays a key role allowing an accurate identification of myocardial tissue abnormalities, which could affect athletes' prognosis. This review focuses on characteristics of premature ventricular contractions characteristics in terms of morphology, distribution, complexity and response to exercise and describes the possible underlying myocardial substrates. This review also critically analyzes the evaluation process of athletes with premature ventricular contractions necessary for an accurate risk stratification.

Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.