Left ventricular mechanical dispersion predicts arrhythmic risk in mitral valve prolapse

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.

Peak strain dispersion within the left ventricle detected by two-dimensional speckle tracking in patients with uncomplicated systemic lupus erythematosus

Systemic lupus erythematosus (SLE) often leads to various cardiovascular diseases. We aimed to investigate the value of peak strain dispersion (PSD) in evaluating left ventricular dysfunction in patients with uncomplicated SLE. Eighty-seven female SLE patients and fifty-nine healthy female controls were recruited. The SLE patients were divided into inactive disease (SLE disease activity index (SLEDAI) ≤ 4; n = 48) and active disease (SLEDAI ≥ 5; n = 39) subgroups. Traditional echocardiography and two-dimensional speckle-tracking echocardiography were performed using a GE VividE9 ultrasound diagnostic system and an advanced quantitative analysis EchoPAC workstation (version 201), respectively. The global longitudinal strain (GLS) in the SLE with SLEDAI ≤ 4 group was comparable to that in the control group (- 19.89% vs - 20.7%; P = 0.061). However, GLS was obviously damaged in the SLE with SLEDAI ≥ 5 group compared with that in the control group (- 19.07% vs - 20.7%; P < 0.001). PSD impairment was observed in the SLE with SLEDAI ≤ 4 group (33.83 ms vs 31.44 ms; P = 0.012) and SLE with SLEDAI ≥ 5 groups (52.31 ms vs 31.44 ms; P < 0.001), but the largest difference was observed in the active disease group. Linear regression analysis showed that PSD was moderately correlated with the SLEDAI (r = 0.535; P < 0.001) in SLE patients with SLEDAI ≤ 4 and showed the best correlation with the SLEDAI (r = 0.646; P < 0.001) in the SLE patients with SLEDAI ≥ 5. A correlation between GLS and the SLEDAI (r = 0.359; P = 0.025) was found in the active disease group but not in the inactive disease group (r = 0.253; P = 0.082). PSD is more comprehensive and accurate for evaluating left ventricular subclinical dysfunction in SLE patients. In inactive SLE patients, PSD is a more sensitive index to evaluate early systolic dysfunction of the left ventricle. GLS may be a more vulnerable indicator of early left ventricular cardiac dysfunction in active SLE patients. Controlling disease activity may reduce the events of cardiac dysfunction.

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.

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.

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.

Value of peak strain dispersion in discovering left ventricular dysfunction in diabetes mellitus

Cardiovascular disease is one of the main causes of death in diabetes mellitus (DM) patients. The aim of the current study was to explore the value of peak strain dispersion (PSD) for discovering early-stage left ventricular (LV) dysfunction in type 2 diabetes mellitus (T2DM) patients. One hundred and one T2DM patients and sixty healthy subjects were selected for this study. T2DM patients were further divided into controlled blood glucose (HbA1c < 7%, n = 46) and uncontrolled blood glucose (HbA1c ≥ 7%, n = 55) subgroups. All participants underwent conventional echocardiography and two-dimensional speckle-tracking echocardiography. Our results showed that an obvious difference was not observed in global longitudinal strain (GLS) between the controlled blood glucose group and the control group (− 20.34% vs − 21.22%, P = 0.068). Compared with the healthy controls, the uncontrolled blood glucose group showed an impaired GLS (− 18.62% vs − 21.22%, P < 0.001). Nevertheless, PSD was appreciably increased in the controlled blood glucose group (36.02 ms vs 32.48 ms, P = 0.01) and uncontrolled blood glucose group (57.51 ms vs 32.48 ms, P < 0.001). Multivariate linear regression analysis showed that HbA1c was closely related to PSD lesion in the LV in the T2DM group (β = 0.520, P < 0.001). PSD plays an important role in evaluating the coordination and synchronization of myocardial movement and provides a more accurate and sensitive index assessment of early LV systolic function in T2DM patients. In addition, HbA1c levels were related to LV dysfunction.

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.

Combined right and left ventricular mechanical dispersion enhance the arrhythmic risk stratification in hypertrophic cardiomyopathy

BACKGROUND

Ventricular arrhythmias are the most frequent cause of sudden cardiac death in individuals with hypertrophic cardiomyopathy (HCM). In the present study we investigated if combined left ventricular (LV) and right ventricular (RV) mechanical dispersion (MD) are correlated with ventricular arrhythmias. We aimed also to analyze if MD enhances the arrhythmic risk stratification in HCM.

METHODS

The cohort included 47 subjects with HCM and 36 healthy individuals. All the studied population underwent clinical, 24-h electrocardiographic (ECG) monitoring for detection and description of non-sustained ventricular tachycardia (NSVT) in terms of number of events, maximal rate and length and comprehensive transthoracic echocardiography, including strain rate imaging. MD was calculated as standard deviation of time from the peak of R wave on ECG to maximum LV or RV shortening in 17 LV and 3 RV segments.

RESULTS

HCM subjects with NSVT on ECG monitoring had increased LVMD (81±18ms vs 42±8ms) and RVMD (52±26 vs 25±23ms) compared with the HCM group without NSVT or compared with the healthy controls. On receiver operating characteristic curves the cut-off values associated with optimal specificity and sensitivity were 62ms for LVMD and 39ms for RVMD. LVMD (OR=1.86, 95% CI 1-1.06, p=0.01) and RVMD (OR=1.04, 95% CI 1.01-1.07, p=0.003) were the only independent variables that correlated with longer and faster NSVT and furthermore improved the risk stratification of NSVTs.

CONCLUSIONS

In a cohort of subjects with HCM, LVMD and RVMD correlates with the presence of NSVT on ECG monitoring. Combined LVMD and RVMD may improve the risk stratification of HCM with NSVT.

Fragmented QRS may be associated with complex ventricular arrhythmias in mitral valve prolapse

BACKGROUND

Although mitral valve prolapse (MVP) is a benign disease, several studies have indicated its association with ventricular arrhythmias (VAs). Some histopathological studies have pointed to left ventricular fibrosis as the underlying cause of arrhythmia in MVP patients. Fragmented QRS (fQRS) on electrocardiography (ECG) has been shown to be a marker of myocardial fibrosis. This study aimed to investigate the association between fQRS and complex VAs in patients with MVP.

METHODS

A total of 230 consecutive patients who were diagnosed with MVP were included in the study. The control group consisted of 302 healthy individuals matched according to age and sex. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. All patients underwent 24-hour Holter monitoring and VAs were classified using Lown's scoring system. Lown class ≥3 VAs were considered as complex VAs.

RESULTS

As compared to the healthy individuals, prevalence of fQRS (40% vs. 9.6%, P<0.001) and complex VAs (18.7% vs. 0%, P<0.001) were significantly higher in patients with MVP. Furthermore, complex VAs (35.9% vs. 7.2%, P=0.001) were significantly higher in MVP patients with fQRS. In multiple logistic regression analysis, the presence of bileaflet prolapse (OR: 2.567, 95%CI: 1.434 to 4.367; P=0.002) and presence of fQRS (OR: 3.021, 95%CI: 1.556 to 6.232; P<0.001) were independent predictors for complex VAs.

CONCLUSIONS

The presence of fQRS may be associated with complex VAs in patients with MVP. Therefore, fQRS may be used in risk stratification of complex VAs in patients with MVP.