Tricuspid Annulus Disjunction: Novel Findings by Cardiac Magnetic Resonance in Patients With Mitral Annulus Disjunction

When annuloplasty is not enough: a case report of ventricular arrhythmias stepwise abolition after mitral valve re-repair

Background

Some patients affected by mitral valve (MV) prolapse (MVP) are at higher risk of ventricular arrhythmias (VAs), but the underlying pathogenesis, as well as the effects of surgery on VA, remain not fully understood. Mitral valve repair, however, represents a privileged point of view to deepen the understanding of arrhythmogenesis in this context. Hence, we report an interesting case of MV re-repair.

Case summary

A 52-year-old man was referred to our institution for severe mitral regurgitation (MR) due to P2 prolapse in the context of myxomatous MV degeneration. Pre-operative imaging showed systolic mitral annular disjunction, left ventricular (LV) wall curling, Pickelhaube's sign, and a prolapsing tricuspid valve (TV) with only mild regurgitation. Twenty-four-hour electrocardiogram (ECG) Holter revealed a significant burden of premature ventricular contractions (PVCs), most of them originating from anterior papillary muscle (APM), posterior papillary muscle (PPM), and mitral annulus (MA). Quadrangular resection of P2 and mitral annuloplasty were performed. One year later, relapse of severe MR due to a residual P2M1 prolapse occurred. Twenty-four-hour ECG Holter showed no PVCs from PPM and MA, while those from APM persisted. A central edge-to-edge repair was effectively used to fix the residual prolapse. After 1 year from REDO surgery, a third ECG Holter confirmed the absence of any remaining LV PVCs, but still few ectopic beats originating from TV were recorded.

Discussion

Here, we report a case of VA resolution after specific, anatomical triggers addressing surgical gestures. Our experience confirms that MV surgery may have a role in MVP patients' arrhythmias correction.

Current management of tricuspid regurgitation: a focus on the spiral suspension approach

The indication for surgery for tricuspid regurgitation (TR) has reached a major turning point. It has become clear that the presence of moderate or severe TR alone worsens the prognosis of life, and the previous guidelines of Japanese Circulation Society, in which the indication for surgery was recommended at the timing of "right heart failure difficult to treat medically," now recommends surgery with a trigger of "repeated right heart failure" in the 2020 edition. In addition, a new repair technique targeting at subvalvular structure has been developed for end-stage TR to overcome a high TR recurrence rate that is associated with severe right ventricular enlargement and leaflet tethering. This review focuses on the spiral suspension technique, in which the papillary muscles are spirally suspended towards the septal leaflet annulus to correct tethering and enhances the understanding of its application in the context of TR management.

Tricuspid annular disjunction with varying degrees of tricuspid regurgitation in the setting of Takotsubo syndrome

Tricuspid annular disjunction (TAD) is concomitant in approximately half of mitral annular disjunction (MAD) cases. Here we report a case of echocardiographically isolated TAD detected during Takotsubo syndrome (TTS) complicated by a transient aggravation of tricuspid regurgitation. An 87-year-old female was admitted at the emergency department with ST segment elevation. Coronary angiography findings were consistent with TTS. Transthoracic echocardiography (TTE) showed a left ventricular apical aneurysm with incidental finding of TAD with 'torrential' tricuspid regurgitation. Importantly, no concomitant MAD was detected on TTE. No significant arrhythmias were detected on telemetry surveillance. Follow up TTE showed improvement in left ventricular function with reduced regional wall abnormalities. TAD was still present although the tricuspid regurgitation had reduced to 'moderate'. The patient was discharged home after 23 days of hospital stay. The present case illustrates the need of further investigations into TAD and its clinical implications for acute TR in TTS.

Severe tricuspid regurgitation with biannular disjunction requiring surgical treatment: a case report

Background

Tricuspid annular disjunction (TAD) is an annular disjunction of the right-sided heart. Although TAD is often concomitant with mitral annular disjunction (MAD), it often presents as mitral regurgitation (MR), rather than tricuspid regurgitation (TR). While the clinical significance of MAD has been well-established, there is still little data on TAD. This is a rare case of severe TR due to TAD that appears to be isolated from MAD.

Case summary

A 63-year-old female complaining of pre-syncope and dyspnoea on exertion was referred to our department. Initial transthoracic echocardiography showed MR and TR due to tricuspid valve prolapse (TVP). On transoesophageal echocardiography, the TVP consisted of an excessively redundant anterior leaflet, where the annular disjunction and severe regurgitation were formed. She recently underwent mitral and tricuspid valve plasties for symptomatic primary severe TR.

Discussion

This case report emphasizes the clinical significance of TAD as a potential cause of severe TR, even without significant MR. Tricuspid annular disjunction progresses more gradually compared with MAD. This case suggests that remodelling of the right atrium, particularly in chronic atrial fibrillation, may contribute to the development of TR. Despite diagnostic challenges due to the flexible and dynamic nature of the tricuspid annulus, this is the first report of TAD-induced severe TR necessitating surgical intervention. Accurately diagnosing TAD remains challenging with current imaging modalities, emphasizing the need for improved diagnostic tools to optimize treatment strategies.

Mitral annular disjunction; how accurate are we? A cardiovascular MRI study defining risk

Aims

Mitral Annular Disjunction (MAD) refers to embryologic fibrous separation between mitral annular ring and basal left ventricular myocardium. Since its original description, the role of MAD in arrhythmic mitral valve prolapse (MVP) has been the subject of active research. In this study we sought to assess prognostic and imaging characteristics of MVP patients with and without underlying MAD.

Methods and results

Patients with posterior or bi-leaflet MVP were retrospectively identified via a review of all patients referred to our cardiac magnetic resonance (CMR) imaging laboratory from January 2015 to May 2022. MVP patients were further stratified by underlying MAD status. A total of 100 MVP patients undergoing CMR imaging (52 MVP patients with posterior MAD) were retrospectively identified with female comprising 55 % of the cohort. MVP patients with MAD were more likely to have an abnormal basal inferolateral/ papillary muscles LGE (51 % vs 21 %, p < 0.01). Posterior MAD longitudinal disjunction gap in 'mm' was a predictor of ventricular tachycardia (VT) [1.29, p = 0.01)]. Using ROC curve analysis, a disjunction gap of ≥ 4 mm was predictive of VT (AUC-0.71, p < 0.01), and incorporation of LGE in ROC model further improved AUC to 0.78 confirmed via Akaike information criterion (p < 0.01).

Conclusion

Abnormal LGE involving basal inferolateral myocardium and papillary muscles may provide etiologic substrate for arrythmia in MVP patients.

Mitral Annular Disjunction: Review of an Increasingly Recognized Mitral Valve Entity

Mitral annular disjunction (MAD) refers to atrial displacement of the hinge point of the mitral valve annulus from the ventricular myocardium. MAD leads to paradoxical expansion of the annulus in systole and may often be associated with mitral valve prolapse (MVP), leaflet degeneration, myocardial and papillary muscle fibrosis, and, potentially, malignant cardiac arrhythmias. Patients with MAD and MVP may present similarly, and MAD is potentially the missing link in explaining why some patients with MVP experience adverse outcomes. Patients with a 5 mm or longer MAD distance have an elevated risk of malignant cardiac arrhythmia compared with those with a shorter MAD distance. Evaluation for MAD is an important component of cardiac imaging, especially in patients with MVP and unexplained cardiac arrhythmias. Cardiac MRI is an important diagnostic tool that aids in recognizing and quantifying MAD, MVP, and fibrosis in the papillary muscle and myocardium, which may predict and help improve outcomes following electrophysiology procedures and mitral valve surgery. This article reviews the history, pathophysiology, controversy, prevalence, clinical implications, and imaging considerations of MAD, focusing on cardiac MRI. Keywords: MR-Dynamic Contrast Enhanced, Cardiac, Mitral Valve, Mitral Annular Disjunction, Mitral Valve Prolapse, Floppy Mitral Valve, Cardiac MRI, Arrhythmia, Sudden Cardiac Death, Barlow Valve © RSNA, 2023.

Arrhythmic mitral valve prolapse and mitral annular disjunction: pathophysiology, risk stratification, and management

Mitral valve prolapse (MVP) is the most frequent valve condition but remains a conundrum in many aspects, particularly in regard to the existence and frequency of an arrhythmic form (AMVP) and its link to sudden cardiac death. Furthermore, the presence, frequency, and significance of the anatomic functional feature called mitral annular disjunction (MAD) have remained widely disputed. Recent case series and cohorts have shattered the concept that MVP is most generally benign and have emphasized the various phenotypes associated with clinically significant ventricular arrhythmias, including AMVP. The definition, evaluation, follow-up, and management of AMVP represent the focus of the present review, strengthened by recent coherent studies defining an arrhythmic MVP phenotypic that would affect a small subset of patients with MVP at concentrated high risk. The role of MAD in this context is of particular importance, and this review highlights the characteristics of AMVP phenotypes and MAD, their clinical, multimodality imaging, and rhythmic evaluation. These seminal facts lead to proposing a risk stratification clinical pathway with consideration of medical, rhythmologic, and surgical management and have been objects of recent expert consensus statements and of proposals for new research directions.

Arrhythmogenic Mitral Valve Prolapse and Sudden Cardiac Death: An Update and Current Perspectives

Mitral valve prolapse (MVP) affects about 2% to 3% of the general population, mostly women, and is the most common cause of primary chronic mitral regurgitation (MR) in western countries. The natural history is heterogeneous and widely determined by the severity of MR. Although most patients remain asymptomatic with a near-normal life expectancy, approximately 5% to 10 % progress to severe MR. As largely recognized, left ventricular (LV) dysfunction due to chronic volume overload per se identifies a subgroup at risk of cardiac death. However, there is rising evidence of a link between MVP and life threating ventricular arrhythmias (VAs)/sudden cardiac death (SCD) in a small subset of middle-aged patients without significant MR, heart failure and remodeled hearts. The present review focuses on the underlying mechanism of electric instability and unexpected cardiac death in this subset of young patients, from the myocardial scarring of the LV infero-lateral wall due to mechanical stretch exerted by the prolapsing leaflets and mitral annular disjunction, to the inflammation's impact on fibrosis pathways along with a constitutional hyperadrenergic state. The heterogeneity of clinical course reveals a necessity of risk stratification, preferably through noninvasive multimodality imaging, that will help to identify and prevent adverse scenarios in young MVP patients.

Prevalence and Clinical Implications of Tricuspid Valve Prolapse Based on Magnetic Resonance Diagnostic Criteria

BACKGROUND

Tricuspid valve prolapse (TVP) is an uncertain diagnosis with unknown clinical significance because of a scarcity of published data.

OBJECTIVES

In this study, cardiac magnetic resonance was used to: 1) propose diagnostic criteria for TVP; 2) evaluate the prevalence of TVP in patients with primary mitral regurgitation (MR); and 3) identify the clinical implications of TVP with regard to tricuspid regurgitation (TR).

METHODS

Forty-one healthy volunteers were analyzed to identify normal tricuspid leaflet displacement and propose criteria for TVP. A total of 465 consecutive patients with primary MR (263 with mitral valve prolapse [MVP] and 202 with nondegenerative mitral valve disease [non-MVP]) were phenotyped for the presence and clinical significance of TVP.

RESULTS

The proposed TVP criteria included right atrial displacement of ≥2 mm for the anterior and posterior tricuspid leaflets and ≥3 mm for the septal leaflet. Thirty-one (24%) subjects with single-leaflet MVP and 63 (47%) with bileaflet MVP met the proposed criteria for TVP. TVP was not evident in the non-MVP cohort. Patients with TVP were more likely to have severe MR (38.3% vs 18.9%; P < 0.001) and advanced TR (23.4% of patients with TVP demonstrated moderate or severe TR vs 6.2% of patients without TVP; P < 0.001), independent of right ventricular systolic function.

CONCLUSIONS

TR in subjects with MVP should not be routinely considered functional, as TVP is a prevalent finding associated with MVP and more often associated with advanced TR compared with patients with primary MR without TVP. A comprehensive assessment of tricuspid anatomy should be an important component of the preoperative evaluation for mitral valve surgery.

Ventricular arrhythmias in arrhythmic mitral valve syndrome-a prospective continuous long-term cardiac monitoring study

AIMS

Arrhythmic mitral valve syndrome is linked to life-threatening ventricular arrhythmias. The incidence, morphology and methods for risk stratification are not well known. This prospective study aimed to describe the incidence and the morphology of ventricular arrhythmia and propose risk stratification in patients with arrhythmic mitral valve syndrome.

METHODS

Arrhythmic mitral valve syndrome patients were monitored for ventricular tachyarrhythmias by implantable loop recorders (ILR) and secondary preventive implantable cardioverter-defibrillators (ICD). Severe ventricular arrhythmias included ventricular fibrillation, appropriate or aborted ICD therapy, sustained ventricular tachycardia and non-sustained ventricular tachycardia with symptoms of hemodynamic instability.

RESULTS

During 3.1 years of follow-up, severe ventricular arrhythmia was recorded in seven (12%) of 60 patients implanted with ILR [first event incidence rate 4% per person-year, 95% confidence interval (CI) 2-9] and in four (20%) of 20 patients with ICD (re-event incidence rate 8% per person-year, 95% CI 3-21). In the ILR group, severe ventricular arrhythmia was associated with frequent premature ventricular complexes, more non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance (all P < 0.02).

CONCLUSIONS

The yearly incidence of ventricular arrhythmia was high in arrhythmic mitral valve syndrome patients without previous severe arrhythmias using continuous heart rhythm monitoring. The incidence was even higher in patients with secondary preventive ICD. Frequent premature ventricular complexes, non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance were predictors of first severe arrhythmic event.

Imaging Considerations and Clinical Implications of Mitral Annular Disjunction

Mitral annular disjunction is increasingly recognized as an important anatomic feature of mitral valve disease. The presence of mitral annular disjunction, defined as separation between the left atrial wall at the point of mitral valve insertion and the left ventricular free wall, has been associated with increased degeneration of the mitral valve and increased incidence of sudden cardiac death. The clinical importance of this entity necessitates standard reporting on cardiovascular imaging reports if patients are to receive adequate risk stratification and management. We provide a narrative review of the literature pertaining to mitral annular disjunction, its clinical implications, and areas needing further research.

Tricuspid annular disjunction can be isolated and even arrhythmogenic. A cardiac magnetic resonance study

Mitral annular disjunction is related to increased arrhythmogenic risk; in a certain percentage of cases, mitral annular disjunction is associated with tricuspid annular disjunction. While the prognostic implications of mitral annular disjunction have been well established, there is still little data to define this aspect regarding the tricuspid annular disjunction. We present a case of a patient admitted for life-threatening ventricular arrhythmias that occurred during endurance sporting activity, who was found to have isolated tricuspid annular disjunction, not associated with mitral annular disjunction. Based on several factors, including the morphology and axis of QRS of the ventricular arrhythmic activity, and its behavior, including the response to antiarrhythmic treatment, and in keeping with the finding of edema and late gadolinium enhancement at the basal segment of the right ventricle free wall on cardiac magnetic resonance imaging, a direct relation between tricuspid annular disjunction and ventricular arrhythmias was highly conceivable. Control after three months showed almost complete remission of the previously described and persistence of LGE at the level of the basal segment of the free wall of the right ventricle, so giving strength to the hypothesis of an event related to increased acute RV free wall stress, secondary to high-intensity physical activity, established on a framework of chronic wall stress, as represented by LGE, similarly to what happens for mitral valve prolapse. To the best of our knowledge, this is the first case of a legitimately conceivable direct relation between tricuspid annular disjunction and ventricular arrhythmias.

Does Anatomic Phenotype of Mitral Annular Disjunction Impact Survival? An Autopsy-Based Retrospective Study

Controversies have been raised regarding the prevalence and potential clinical significance of mitral annular disjunction (MAD). We aim to address the anatomic characteristics of MAD and their association, if any, on survival. We retrospectively reviewed 1373 consecutive dissected hearts (1017 men, mean age at death 44.9 ± 0.4 y) and frequently detected MAD (median disjunctional length: 2.0 mm, range: 1.5 mm~8.5 mm), with the prevalence of 92.1% over the entire mitral annulus and 74.9% within the posterior annulus (pMAD). The presence of pMAD was associated with increased all-cause mortality (45 y vs. 49 y, hazard ratio [HR]: 1.28, 95% confidence interval [CI]: 1.11~1.47, p < 0.001), which persisted in the context of cardiovascular diseases (CVDs; 46 y vs. 51 y, HR: 1.33, 95% CI: 1.14~1.56, p < 0.001) but was insignificant in those without CVDs. Compared to those without pMAD, individuals with pMAD affecting the entire posterior annulus or having a mean standardized length of ≥1.78 showed other clinically significant cardiovascular phenotypes, including the enlargement of aortic annular circumferences and a higher occurrence of thoracic aortic aneurysm/dissection. This largest series of autopsies show that MAD is a common phenotype that may exert additive influence on the survival of individuals. It is necessary to establish a precise classification and stratification of MAD.