Right ventricular dysfunction in hypertrophic cardiomyopathy as evidenced by the myocardial performance index

Right ventricular function declines prior to left ventricular ejection fraction in hypertrophic cardiomyopathy

BACKGROUND

The right ventricle (RV) in hypertrophic cardiomyopathy (HCM) tends to be neglected, as previous efforts have predominantly focused on examining the prognostic value of left ventricular (LV) abnormalities. The objectives of this study were to assess RV function in HCM, changes over time, and association with clinical outcomes.

METHODS

Two hundred and ninety HCM patients with preserved LV ejection fraction (LVEF ≥ 55%) and 30 age- and sex-matched controls underwent cardiovascular magnetic resonance (CMR). All patients were followed up for clinical events for a median duration of 4.4 years. Sixty-three patients had a follow-up CMR undertaken at a median interval of 5.4 years. Main study measures and outcomes were RV function (RV ejection fraction (RVEF) and RV strain) at baseline, temporal changes in RV function over time and prognostic value of RV dysfunction for predicting cardiovascular outcomes in HCM.

RESULTS

When compared to controls, HCM patients exhibited lower RV and LV peak global longitudinal systolic strains on feature-tracking analysis of cine images, while RVEF and LVEF were within the normal range. On follow-up CMR, both RV and LV strain parameters decreased over time. RVEF decreased at follow-up (65 ± 7% to 62 ± 7%, P < 0.001) but the change in LVEF was not significant (68 ± 10% to 66 ± 8%, P = 0.30). On clinical follow up, reduced RVEF was an independent predictor of non-sustained ventricular tachycardia (NSVT) [HR 1.10 (95% CI 1.06-1.15), P < 0.001] and composite cardiovascular events (NSVT, stroke, heart failure hospitalisation and cardiovascular death) [HR 1.07 (95% CI 1.03-1.10), P < 0.001]. RV longitudinal strain was an independent predictor of NSVT [HR 1.05 (95% CI 1.01-1.09), P = 0.029]. Patients with RVEF < 55% showed an increased risk of NSVT and composite cardiovascular events. In contrast, LVEF and LV global longitudinal strain were not predictive of such events on multivariable analysis.

CONCLUSIONS

In HCM, RV function, including RV strain, and LV strain decrease over time despite preserved LVEF. Reduction in RV but not LV function is associated with adverse cardiovascular outcomes. Assessing RV function in early HCM disease might have a role in risk stratification to prevent future cardiovascular events.

Right Ventricular Enlargement and Dysfunction Are Associated With Increased All-Cause Mortality in Hypertrophic Cardiomyopathy

OBJECTIVE

To assess whether right ventricular enlargement (RVE) and right ventricular dysfunction (RVD) adversely affect prognosis in hypertrophic cardiomyopathy (HCM).

PATIENTS AND METHODS

Data were retrieved from Mayo Clinic's prospectively collected HCM registry between January 1, 2000, and September 30, 2012. Right ventricle (RV) size and function were semiquantitatively categorized via echocardiography as normal (RV-Norm) versus abnormal (RV-Abn) (RVE or RVD). All-cause mortality was the primary endpoint.

RESULTS

Of 1878 HCM patients studied (mean age 53±15 years; 41.6% female), only 71 (3.8%) had RV-Abn (24 RVE, 28 RVD, 19 combined RVE and RVD). Compared with HCM patients with RV-Norm, RV-Abn patients were older (57±14 vs 53±15 years, P=.02), more symptomatic (New York Heart Association functional class III-IV in 62.0% vs 48.6%, P=.03), had more atrial fibrillation (53.5% vs 17.3%, P<.001), and more prior implantable cardioverter-defibrillator implantation (23.9% vs 11.3%, P=.02). Median follow-up was 9.4 years with 311 deaths. Patients who were RV-Abn had higher all-cause mortality compared with RV-Norm (log-rank P<.001); 24.1% (95% CI, 15.5% to 35.3%) vs 6.1% (95% CI, 5.1% to 7.3%) at 5 years. In multivariable Cox modeling, RV-Abn (hazard ratio, 1.89; 95% CI, 1.18 to 3.03; P=.008) was associated independently with all-cause mortality after adjusting for age, female sex, New York Heart Association functional class, atrial fibrillation, hypertension, coronary artery disease, implantable cardioverter-defibrillator implantation, beta blocker use, prior septal reduction therapy, resting LV outflow tract gradient, maximal LV wall thickness, and moderate or greater tricuspid regurgitation.

CONCLUSION

Although perturbations in RV size and function were observed in fewer than 5% of patients with HCM, they were associated with nearly two-fold higher all-cause mortality at long-term follow-up.

Right ventricular involvement in hypertrophic cardiomyopathy: evidence and implications from current literature

Objectives. In current guidelines, hypertrophic cardiomyopathy (HCM) is defined by hypertrophy of the left ventricle (LV). Less attention has been given to the right ventricle (RV) in patients with HCM. We wanted to provide an overview of current literature on RV involvement in HCM. Design. We performed a systematic search in PubMed and added additional articles by manual screening of references. The quality of the articles was assessed according to the GRADE system. Results. We identified 35 original articles on RV involvement in HCM. Based on these publications, RV hypertrophy occurs in 28-44% of HCM patients, depending on the cut-off value for hypertrophy and the method for assessment. Histological studies show the same structural changes in RV as are typically described in the LV cardiomyocyte hypertrophy and disarray, as well as fibrosis. These changes are similar, but less pronounced in the RV than in the LV. We discuss how HCM can impact the RV, either through a primary involvement similar to the LV or secondary to hemodynamic effects resulting from LV dysfunction. RV dysfunction in HCM is associated with higher mortality, partly due to an increased risk of ventricular tachycardia and sudden cardiac death. Conclusions. The evidence for RV involvement in HCM is limited. Multimodal imaging assessment of the RV should be included in the work-up of patients with HCM, and the added value of including RV function in the risk stratification algorithm should be further explored.

The prognostic value of biventricular long axis strain using standard cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

BACKGROUND

Long axis strain (LAS) is a parameter derived from standard cardiovascular magnetic resonance imaging. However, the prognostic value of biventricular LAS in hypertrophic cardiomyopathy (HCM) is unknown.

METHODS

Patients with HCM (n = 384) and healthy volunteers (n = 150) were included in the study. Left ventricular (LV)-LAS was defined as the percentage change in the length measured from the epicardial border of the LV apex to the midpoint of a line connecting the mitral annulus at end-systole and end-diastole. Right ventricular (RV)-LAS represented the percentage change of length between epicardial border of the LV apex to the midpoint of a line connecting the tricuspid annulus at end-systole and end-diastole. The primary endpoint was a combination of all-cause death and sudden cardiac death aborted by appropriate implantable cardioverter-defibrillator discharge and cardiopulmonary resuscitation after syncope. The secondary endpoint was a combination of the primary endpoint and hospitalization for congestive heart failure.

RESULTS

Twenty-nine patients (7.6%) achieved the primary endpoint, and the secondary endpoint occurred in 66 (17.2%) patients. In multivariate Cox regression analysis, RV-LAS was an independent prognostic factor for the primary (hazard ratio (HR), 1.13) and secondary (HR, 1.11) endpoints. In the subgroup of patients with a normal RV ejection fraction (EF) (>45.0%, n = 345), impaired RV-LAS was associated with adverse outcomes and might add incremental prognostic value to RVEF and tricuspid annular plane systolic excursion (TAPSE) (p < 0.01).

CONCLUSIONS

RV-LAS is an independent predictor of adverse prognosis in HCM in addition to RVEF and TAPSE.

Prevalence and Prognostic Significance of Right Ventricular Dysfunction in Patients With Hypertrophic Cardiomyopathy

Few data are available regarding the prevalence and clinical significance of right ventricular systolic dysfunction (RVSD) in hypertrophic cardiomyopathy (HC) patients. This study aimed to evaluate right ventricular (RV) systolic function by cardiovascular magnetic resonance and explore the prevalence and prognostic significance of RVSD in HC patients. A total of 226 patients with HC assessed by cardiovascular magnetic resonance were included in this retrospective study. RVSD was defined by RV ejection fraction (RVEF) ≤45% and was present in 26 (11.5%) patients. Association between RVSD, clinical characteristics, and outcomes were analyzed. RVEF was significantly lower in patients with RVSD than without RVSD (36.2 ± 7.0% vs 60.5 ± 7.4%, p < 0.001). There was a positive correlation between RVEF and left ventricular ejection fraction (r = 0.45; p < 0.001). During a mean follow-up of 30.5 ± 23.9 months, there were 22 (9.7 %) all-cause mortality, including 12 (5.3%) cardiovascular death. Kaplan-Meier analysis showed a significantly higher risk for cardiovascular mortality in patients with RVSD (p = 0.026), but no significant difference in all-cause mortality (p = 0.118) and heart failure related rehospitalization (p = 0.485). On multivariate Cox regression analysis, RVSD (hazard ratio 5.36; confidence interval 1.39 to 20.77; p = 0.015) and RVEF (hazard ratio 0.94; confidence interval 0.89 to 0.98; p = 0.011) were independent predictors of cardiovascular mortality. In conclusion, RVSD is a common phenotype and a strong independent predictor of cardiovascular mortality in HC patients.

Right ventricular involvement in transthyretin amyloidosis

BACKGROUND

The extent of right ventricular (RV) involvement in transthyretin amyloidosis (ATTR) is unknown.

OBJECTIVES

This study sought to establish the degree of RV involvement in ATTR amyloidosis, and compare findings with RV involvement in hypertrophic cardiomyopathy (HCM).

METHODS

Forty-two patients with ATTR amyloidosis and echocardiographic evidence of cardiac amyloidosis (cardiac ATTR), 19 ATTR patients with normal left ventricular (LV) wall thickness (non-cardiac ATTR), 25 patients with diagnosed HCM and 30 healthy controls were included in this study. Echocardiographic measurements for conventional parameters, as well as RV global and segmental strain, were recorded.

RESULTS

When comparing RV structure and function between cardiac ATTR amyloidosis and HCM patients, only segmental strain differed between the two groups. In cardiac ATTR amyloidosis, we found an RV apex-to-base strain gradient with highest deformation in the apex. This pattern was reversed in patients with HCM.

CONCLUSIONS

RV involvement is common in cardiac ATTR patients. The present study also detected an RV apical sparing pattern in patients with ATTR cardiomyopathy, similar to what has previously been described for the left ventricle in these patients. This pattern was not seen in HCM patients. Further studies are needed to assess the clinical importance of these findings.

The role of human urotensin-II in patients with hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is a genetic condition with the hallmark feature of left ventricular hypertrophy. Human Urotensin-II (hUT-II) is regarded as a cardiovascular autacoid/hormone, and it has cardiac inotropic and hypertrophic properties. Aims of this study were to elucidate the clinical significance of serum hUT-II levels as a potential new biomarker in patients with HCM.

METHODS

This study included 40 HCM patients (60% males and 40% females) and were compared to 30 healthy control subjects (47% males and 53% females. All patients underwent extensive clinical, laboratory, and echocardiographic. Blood samples were taken to test for serum hUT-II levels by commercial ELISA Kit.

RESULTS

Serum hUT-II was significantly higher (p < 0.01) in patients with HCM (15.8 ± 2.1 pmol/L) compared with healthy controls (3.3 ± 1.7 pmol/L). With regard to HCM patient, Serum hUT-II levels were significantly higher in the female with 16.3 ± 1.9 pmol/L than the male with 15.4 ± 2.2 pmol/L (p < 0.05). Among echocardiographic parameters, hUT-II was negatively associated with ejection fraction (r = -0.160, p = 0.324).

CONCLUSION

Results of the first study indicated that serum hUT-II levels were markedly elevated in patients with HCM. Serum hUT-II is a novel biomarker parameter that has clinical use in patients with the severity of LVH.

Echocardiographic assessment of right ventricular systolic function

Assessment of right chamber function has become increasingly popular and important in recent decades, complementing the evaluation of left chamber functional parameters. The late adoption and integration of right ventricular (RV) function into a complete evaluation of cardiac function could be due in part to the difficulty in visualization of the whole right ventricle, inconsistency in the analysis of RV parameters, and poor understanding of the impact of RV function on prognosis. From M-mode to 2-dimensional (2D) measurements of RV size and function, there have been arrays of parameters that provide important information of the right ventricle. However, there are limitations of using 2D echocardiography to quantify RV volume and ejection fraction (EF), and currently accurate measurements of RV volumes and EF can be obtained using cardiac magnetic resonance (CMR) imaging. Using 3-dimensional echocardiography (3DE), the measurements of RV volumes and EF have become feasible and reproducible. Importantly, 3D measurements have been validated against CMR with higher correlation compared to 2D measurements. With the establishment of reference values, 3D echocardiography determined RV volumes and EF have the potential for better understanding of RV function and exploration of its significance for outcome research in various clinical scenarios.

Role of Two-Dimensional Speckle-Tracking Echocardiography Strain in the Assessment of Right Ventricular Systolic Function and Comparison with Conventional Parameters

Despite the already well-known role the right side of the heart plays in many diseases, right ventricular (RV) function has only recently been carefully considered. Echocardiography is the first-line diagnostic technique for the assessment of the right ventricle and right atrium, whereas cardiac magnetic resonance is considered the gold standard but is limited by cost and availability. According to the current guidelines, systolic RV function should be assessed by several conventional measurements, but the efficacy of these parameters as diagnostic and prognostic tools has been questioned by many authors. The development in recent years of myocardial deformation imaging techniques and their application to the right heart chambers has allowed deeper evaluation of the importance of RV function in the pathophysiology of a large number of cardiovascular conditions, but the real value of this new tool has not been completely clarified. The aim of this review is to provide a wide and careful analysis of findings available in the literature about the assessment of RV systolic function by strain measurements, comparing them with conventional parameters and evaluating their role in several clinical settings.

The clinical features, outcomes and genetic characteristics of hypertrophic cardiomyopathy patients with severe right ventricular hypertrophy

Introduction

Severe right ventricular hypertrophy (SRVH) is a rare phenotype in hypertrophic cardiomyopathy (HCM) for which limited information is available. This study was undertaken to investigate the clinical, prognostic and genetic characteristics of HCM patients with SRVH.

Methods

HCM with SRVH was defined as HCM with a maximum right ventricular wall thickness ≥10 mm. Whole-genome sequencing (WGS) was performed in HCM patients with SRVH. Multivariate Cox proportional hazards regression models were used to identify risk factors for cardiac death and events in HCM with SRVH. Patients with apical hypertrophic cardiomyopathy (ApHCM) were selected as a comparison group. The clinical features and outcomes of 34 HCM patients with SRVH and 273 ApHCM patients were compared.

Results

Compared with the ApHCM group, the HCM with SRVH group included younger patients and a higher proportion of female patients and also displayed higher cardiovascular morbidity and mortality. The multivariate Cox proportional hazards regression models identified 2 independent predictors of cardiovascular death in HCM patients with SRVH, a New York Heart Association class ≥III (hazard ratio [HR] = 8.7, 95% confidence interval (CI): 1.43-52.87, p = 0.019) and an age at the time of HCM diagnosis ≤18 (HR = 5.5, 95% CI: 1.24-28.36, p = 0.026). Among the 11 HCM patients with SRVH who underwent WGS, 10 (90.9%) were identified as carriers of at least one specific sarcomere gene mutation. MYH7 and TTN mutations were the most common sarcomere mutations noted in this study. Two or more HCM-related gene mutations were observed in 9 (82%) patients, and mutations in either other cardiomyopathy-related genes or ion-channel disease-related genes were found in 8 (73%) patients.

Conclusions

HCM patients with SRVH were characterized by poor clinical outcomes and the presentation of multiple gene mutations.

Accuracy of quantitative echocardiographic measures of right ventricular function as compared to cardiovascular magnetic resonance

Background

Many echocardiographic parameters have been proposed to evaluate right ventricular (RV) systolic function. We comprehensively assessed a wide range of quantitative echocardiographic parameters in a single cohort compared with same-day cardiovascular magnetic resonance (CMR).

Methods and results

92 subjects were examined prospectively: Group 1 consisted of 46 healthy controls (21 males, 33.4 ± 11.4 years), Group 2 consisted of 46 patients (20 males, 38.5 ± 18.9 years) undergoing RV functional assessment by CMR (1.5 T). Echocardiography was performed on the same day as CMR; fractional area change (RVFAC), myocardial performance index via spectral Doppler (RVMPI), RVMPI via Doppler tissue imaging (RVMPI-DTI), peak systolic myocardial velocity by DTI (RVSm), tricuspid annular plane systolic excursion (TAPSE), speckle tracking strain, and three dimensional right ventricular ejection fraction (3DE-RV). Linear regression, Bland–Altman and receiver-operator-characteristic (ROC) analyses were performed. At ROC analysis, the most predictive echocardiographic methods were; RVFAC (AUC = 0.892), RVMPI (AUC 0.785), TAPSE (AUC 0.849) and 3DE-RV (AUC 0.909). 3DE-RV appeared the most accurate compared to CMR, although underestimated true RV volumes.

Conclusion

As compared to CMR; 3DE-RV, RVFAC, TAPSE and RVMPI were the most reliable predictors of RV function. These parameters can be recommended for clinical use.

Echocardiographic Assessment of Right Atrial Pressure in a Pediatric and Young Adult Population

Right atrial pressure (RAP) reflects right-sided cardiac hemodynamics and is useful in management of patients with cardiac and systemic disease. Studies in older adults demonstrated that inferior vena cava (IVC) diameter, IVC collapsibility index, hepatic vein systolic filling fraction (SFF), and right atrial volume (RAV) correlated with mean RAP at catheterization. This study aimed to assess the utility of echocardiographic parameters for assessment of RAP in children and young adults. Patients with pulmonary hypertension or heart transplantation undergoing right heart catheterization were recruited for this prospective observational pilot study. Transthoracic echocardiographic assessment of RAP was performed simultaneously with catheterization. For each parameter, three consecutive cardiac cycles were recorded. Long- and short-axis images of the IVC were obtained. RAV was assessed by area-length and biplane methods. IVC diameters and RAV were indexed to body surface area (BSA)(0.5) and (BSA)(1.4), respectively. Relationships between echocardiographic parameters and mean RAP were correlated using "Pearson's r." Fifty subjects aged 0.3-23 years (median 13, mean 12.3 ± 7 years) were enrolled. Mean RAP correlated modestly with RAV (r = 0.51, p < 0.001). Long-axis IVCmax (r = 0.30, p < 0.05) and tricuspid E wave velocity (r = 0.36, p < 0.01) also correlated with mean RAP. RV free wall tissue Doppler velocities, IVC collapsibility index, and hepatic vein SFF had no relation to mean RAP. In a pediatric and young adult population with pulmonary hypertension or heart transplantation, echocardiographic assessment of RAV and long-axis IVCmax provided a reasonable estimate of mean RAP. IVC collapsibility index and hepatic vein SFF demonstrated no association with mean RAP.

Right Ventricular and Right Atrial Involvement Can Predict Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy?

OBJECTIVES AND BACKGROUND

Atrial fibrillation (AF) is associated with clinical deterioration, stroke and disability in patients with hypertrophic cardiomyopathy (HCM). Therefore, the objective of this study was to evaluated cardiac magnetic resonance (CMR)-derived determinants for the occurrence of AF in patients with HCM.

METHODS

98 Patients with HCM and 30 healthy controls underwent CMR and were followed-up for 6 ± 3 years.

RESULTS

19 (19.4%) patients presented with AF at initial diagnosis, 19 (19.4%) developed AF during follow-up and 60 (61.2%) remained in sinus rhythm (SR). Compared to healthy controls, patients with HCM who remained in SR presented with significantly increased left ventricular mass, an elevated left ventricular remodeling index, enlarged left atrial volumes and reduced septal mitral annular plane systolic excursion (MAPSE) compared to healthy controls. Whereas HCM patients who presented with AF at initial diagnosis and those who developed AF during follow-up additionally presented with reduced tricuspid annular plane systolic excursion (TAPSE) and right atrial (RA) dilatation. Receiver-operator curve analysis indicated good predictive performance of TAPSE, RA diameter and septal MAPSE (AUC 0.73, 0.69 and 0.71, respectively) to detect patients at risk of developing AF.

CONCLUSION

Reduced MAPSE measurements and enlarged LA volumes seems to be a common feature in patients with HCM, whereas reduced TAPSE and RA dilatation only seem to be altered in patients with history of AF and those developing AF. Therefore, they could serve as easy determinable markers of AF in patients with HCM.

Coronary sinus dilatation is a sign of impaired right ventricular function in patients with heart failure

OBJECTIVE

The coronary sinus (CS) has been largely ignored by physicians due to a lack of adequate data about the importance of CS enlargement in patients with heart failure (HF). We aimed to assess whether CS dilatation develops in patients with HF and to demonstrate its relation with global myocardial function of the right ventricle (RV).

METHODS

In this cross-sectional study, 45 healthy subjects and 95 HF patients exhibiting left ventricular systolic dysfunction on echocardiographic examination (EF <45%) secondary to ischemic (n=56) or idiopathic dilated cardiomyopathy (DCM) (n=39) were enrolled. Patients with severe renal dysfunction and/or valve disease were excluded. CS was measured by echocardiography from the posterior atrioventricular groove in the apical four-chamber view. The RV myocardial performance index (MPI), which reflects both systolic and diastolic function of the ventricle, was detected using tissue Doppler imaging, and patients with an RV MPI >0.55 were defined as having impaired RV myocardial function. ANOVA, Kruskal-Wallis, Pearson's correlation, and multivariate logistic regression analyses were used for the statistical analysis.

RESULTS

The CS and RV MPI values were significantly greater both in patients with ischemic and idiopathic DCM than in controls (8.79±1.7 mm and 8.33±2.1 mm vs. 5.74±0.6 mm, and 0.64±0.07 and 0.62±0.08 vs. 0.43±0.02; p<0.001 for both, respectively). For the prediction of HF patients with impaired RV function, the cut-off value for the diameter of the CS was 7.35 mm, with a sensitivity of 83% and a specificity of 79%.

CONCLUSION

The CS diameter can be used as a novel echocardiographic marker that provides information about impaired RV function in patients with HF.

CMR-derived TAPSE measurement: a semi-quantitative method of right ventricular function assessment in patients with hypertrophic cardiomyopathy

Aim

To compare cardiovascular magnetic resonance (CMR)-derived right ventricular fractional shortening (RVFS), tricuspid annular plane systolic excursion with a reference point within the right ventricular apex (TAPSE_in) and with one outside the ventricle (TAPSE_out) with the standard volumetric approach in patients with hypertrophic cardiomyopathy (HCM).

Methods and results

105 patients with HCM and 20 healthy subjects underwent CMR. In patients with HCM, TAPSE_in (r = 0.31, p = 0.001) and RVFS (r = 0.35, p = 0.0002) revealed a significant but weak correlation with right ventricular ejection fraction (RVEF), whereas TAPSE_out (r = 0.57, p < 0.0001) showed a moderate correlation with RVEF. The ability to predict RVEF < 45 % in HCM patients was best for TAPSE_out. In patients with hypertrophic obstructive cardiomyopathy (HOCM), RVEF showed a significant but weak correlation with TAPSE_out (r = 0.36, p = 0.02) and no correlation with TAPSE_in (r = 0.05, p = 0.07) and RVFS (r = 0.02, p = 0.2). In patients with hypertrophic non-obstructive cardiomyopathy (HNCM), there was a moderate correlation between RVEF and TAPSE_out (r = 0.57, p < 0.0001) and a weak correlation with TAPSE_in (r = 0.39, p = 0.001) and RVFS (r = 0.38, p = 0.002). In the 20 healthy controls, there was a strong correlation between RVEF and all semi-quantitative measurements.

Conclusion

CMR-derived TAPSE_in is not suitable to determine right ventricular function in HCM patients. TAPSE_out showed a good correlation with RVEF in HNCM patients but only a weak correlation in HOCM patients. TAPSE_out might be used for screening but the detection of subtle changes in RV function requires the 3D volumetric approach.

Assessing right ventricular function in patients with hypertrophic cardiomyopathy with cardiac MRI: correlation with the New York Heart Function Assessment (NYHA) classification

Purpose

To determine whether 3.0-T magnetic resonance imaging (MRI) could assess right ventricular (RV) function in patients with hypertrophic cardiomyopathy (HCM), and if this assessment is correlated with the New York Heart Function Assessment (NYHA) classification.

Materials and Methods

Forty-six patients with HCM and 23 normal individuals were recruited. Left and right ventricular function parameters including end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV) and ejection fraction (EF) and dimensions were measured and compared using 3.0-T MRI. RV function parameters between HCM patients and controls were compared using independent sample t tests. A one way ANOVA test with Bonferroni correction was used to determine significant differences among different NYHA groups. Receiver operating characteristic analyses calculated the sensitivity and specificity of RV dysfunction on MRI for the prediction of HCM severity.

Results

Statistical analysis revealed significant differences of left ventricular (LV) and RV volumetric values and masses between the HCM patients and controls (all p<0.05). Within the HCM group, the simultaneously decreased maximum RVEDD correlated well with the LVEDD (r = 0.53; p<0.001). The function and dimension parameters among Class I to III were not determined to be significantly different (all p>0.05). However, significant differences between the Class IV and I-III groups (all P<0.0167) indicated that the diastolic and systolic function in both the RV and LV were impaired in Class IV patients. ROC analyses identified the EDV, ESV and EDD of both the LV and RV with a high sensitivity cutoff value to predict the HCM patients with severe heart failure (Class IV) with high sensitivity and specificity.

Conclusions

RV involvements were comparable to those of LV global function impairments in patients with HCM. The presence of RV dysfunction and decreased dimension on the MRI helped to predict the severe symptomatic HCM with high sensitivity and specificity.

Prevalence and clinical correlates of right ventricular dysfunction in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HC) is a disease that mainly affects the left ventricle (LV), however recent studies have suggested that it can also be associated with right ventricular (RV) dysfunction. The objective of this study was to determine the prevalence of RV dysfunction in patients with HC and its relation with LV function and outcome. A total of 324 consecutive patients with HC who received care at Stanford Hospital from 1999 to 2012 were included in the study. A group of 99 prospectively recruited age- and gender-matched healthy volunteers were used as controls. RV function was quantified using the RV fractional area change, tricuspid annular plane systolic excursion (TAPSE), and RV myocardial performance index (RVMPI). Compared with the controls, the patients with HC had a higher RVMPI (0.51 ± 0.18 vs 0.25 ± 0.06, p <0.001) and lower TAPSE (20 ± 3 vs 24 ± 4, p <0.001). RV dysfunction based on an RVMPI >0.4 and TAPSE <16 mm was found in 71% and 11% of the HC and control groups, respectively. Worst LV function and greater pulmonary pressures were independent correlates of RV dysfunction. At an average follow-up of 3.7 ± 2.3 years, 17 patients had died and 4 had undergone heart transplantation. LV ejection fraction <50% and TAPSE <16 mm were independent correlates of outcome (hazard ratio 3.98, 95% confidence interval 1.22 to 13.04, p = 0.02; and hazard ratio 3.66, 95% confidence interval 1.38 to 9.69, p = 0.009, respectively). In conclusion, RV dysfunction based on the RVMPI is common in patients with HC and more frequently observed in patients with LV dysfunction and pulmonary hypertension. RV dysfunction based on the TAPSE was independently associated with an increased likelihood of death or transplantation.

Right ventricular mechanics in hypertrophic cardiomyopathy using feature tracking

Objectives: Right ventricular (RV) mechanics in hypertrophic cardiomyopathy (HCM) are poorly understood. We investigate global and regional deformation of the RV in HCM and its relationship to LV phenotype, using 2D strain vector velocity imaging (VVI). Methods: 100 HCM patients (42% females, 41 ± 19 years) and 30 control patients were studied using VVI. Longitudinal peak systolic strain (ϵ_sys), strain rate (SR), time to peak (ϵ) (TTP), displacement of RV free wall (RVFW) and septal wall were analyzed. Similar parameters were quantified in LV septal, lateral, anterior and inferior segments. Intra-V-delay was defined as SD of TTP. Inter-V-delay was estimated from TTP difference between the most delayed LV segment & RVFW. Results: ϵ_sys and SR of both RV & LV, showed loss of base to apex gradient and significant decline in HCM (p < 0.001). Deformation variables estimated from RVFW were strongly correlated with each other (r = 0.93, p < 0.0001). Both were directly related to LV ϵ_sys, SR_sys, SR_e, ejection fraction (EF)%, RVFW displacement (P < 0.001) and inversely related to age, positive family history (p < 0.004, 0.005), RV wall thickness, maximum wall thickness (MWT), intra-V-delay, LA volume (P < 0.0001), LVOT gradient (p < 0.02, 0.005) respectively. ROC curves were constructed to explore the cut-off point that discriminates RV dysfunction. Global and RVFW ϵ_sys: − 19.5% shows 77, 70% sensitivity & 97% specificity, SR_sys: − 1.3s^− 1 shows 82, 70% sensitivity & 30% specificity. Multivariate analyses revealed that RVFW displacement (β = − 0.9, p < 0.0001) and global LV SR_sys (β = 5.9, p < 0.0001) are independent predictors of global RV deformation. Conclusions: Impairment of RV deformation is evident in HCM using feature tracking. It is independently influenced by LV mechanics and correlated to the severity of LV phenotype. RVFW deformation analysis and global RV assessment are comparable.

Impaired left ventricular systolic function reserve limits cardiac output and exercise capacity in HFpEF patients due to systemic hypertension

OBJECTIVES

Heart failure (HF) patients with preserved left ventricular (LV) ejection fraction (EF) (HFpEF) due to systemic hypertension (SHT) are known to have limited exercise tolerance. Despite having normal EF at rest, we hypothesize that these patients have abnormal systolic function reserve limiting their exercise capacity.

METHODS

Seventeen patients with SHT (mean age 68 ± 9 years) but no valve disease and 14 healthy individuals (mean age of 65 ± 10 years) underwent resting and peak exercise echocardiography using conventional, tissue Doppler and speckle tracking techniques. The differences between resting and peak exercise values were also analyzed (Δ). Exercise capacity was determined as the workload divided by body surface area.

RESULTS

Resting values for left atrial (LA) volume/BSA (r=-0.66, p<0.001) and global longitudinal strain rate (GLSR) in early (e) and late (a) diastole (r=0.47 and 0.46, p<0.05 for both) correlated with exercise capacity. LVEF increased during exercise in normals (mean Δ EF=10 ± 8%) but failed to do so in patients (mean Δ EF=0.6 ± 9%, p<0.001 between groups). LV GLSR during systole (s) also failed to increase with exercise in patients, to the same extent as it did in normals (0.2 ± 0.2 vs. 0.6 ± 0.3 1/s, p<0.001). The difference between rest and exercise (Δ) in LV lateral wall systolic velocity from tissue Doppler (s') (0.71, p<0.001), Δ in cardiac output (r=0.60, p<0.001) and Δ GLSRs (r=0.48, p<0.05) all correlated with exercise capacity independent of changes in heart rate.

CONCLUSION

HFpEF patients with hypertensive LV disease have significantly limited exercise capacity which is related to left atrial enlargement as well as compromised LV systolic function at the time of the symptoms. The limited myocardial systolic function reserve seems to be underlying important explanation for their limited exercise capacity.

Impact of sildenafil on echocardiographic indices of myocardial performance after the Fontan operation

The objective of this study was describe the impact of sildenafil on echocardiographic measures of myocardial performance in children and young adults with a functional single-ventricle physiology late after Fontan surgery. A double-blind, placebo-controlled, crossover trial was conducted in children and young adults after the Fontan operation at a single pediatric center. Subjects were randomized to receive placebo or sildenafil (20 mg tid) for 6 weeks. After a 6-week washout period, subjects were crossed for an additional 6 weeks. Each subject underwent an echocardiogram at the start and finish of each phase. A total of 27 subjects completed study testing at a mean age of 14.9 years and a mean time from Fontan surgery of 11.3 years. After sildenafil, subjects demonstrated improvement in their myocardial performance index (MPI; -0.051; 95% CI -0.095, -0.0077; p 0.02) and in the product of the velocity time integral (VTI) of the dominant outflow tract and the heart rate (HR; 110 cm × bpm; 95% CI 7.5, 220; p = 0.04). Measures of diastolic performance, including inflow velocities, myocardial velocities, and the ratio of blood pool velocity to myocardial velocity during passive inflow, did not change. In this cohort, there were significant improvements in both the MPI and the product of the VTI × HR after 6 weeks of treatment with sildenafil. These findings suggest that sildenafil may be a useful therapy to improve or maintain ventricular performance in select patients after the Fontan operation.

Right ventricular function in patients with pulmonary hypertension; the value of myocardial performance index measured by tissue Doppler imaging

AIMS

Myocardial performance index (MPI) measured by conventional Doppler is routinely used to assess right ventricular (RV) systolic function in patients with pulmonary hypertension (PH). Our aim was to determine whether MPI measured by Doppler tissue imaging (tMPI) is effective in assessing RV function in these patients.

METHODS AND RESULTS

Retrospectively, we have studied 196 patients with chronic PH [pulmonary arterial systolic pressure (PASP) 81 +/- 40 mmHg] and 37 healthy volunteers (PASP of 27 +/- 7 mmHg). According to the exclusion criteria, 172 patients were included in the final study cohort. All patients were evaluated for RV systolic function by different parameters. MPI was measured by both conventional and tissue Doppler imaging. Bland-Altman analysis showed moderate agreement between MPI and tMPI (the mean difference was -0.02, absolute difference = -0.32 to 0.29; 95% intervals of agreement, percentage of average = -46.6 to 40.8%). In 50 consecutive PH patients where additional parameters were calculated, we found a significant correlation between tMPI and RV ejection fraction (r = -0.73, P< 0.0001) and RV fractional area change (r = -0.58, P< 0.0001). No significant inter- and intra-observer variability was identified.

CONCLUSION

This study demonstrated a moderate agreement between two methods of measuring MPI. A good correlation of tMPI with RV ejection fraction and RV fractional area change was found indicating that tMPI might be superior to MPI Doppler. tMPI is a parameter unaffected by RV geometry and importantly has the advantage of simultaneously recording the time intervals from the same cardiac cycle.