The right ventricle in “Left-sided” cardiomyopathies: The dark side of the moon

The right ventricle (RV) has long been regarded as the forgotten and neglected cardiac chamber and it has been overshadowed by the left ventricle (LV). However, in the last decades, important advances in non-invasive cardiac imaging, from myocardial deformation imaging to cardiovascular magnetic resonance (CMR), have overcome the challenges imposed by the complex anatomy of the right heart, leading to a deep understanding of cardiovascular physiology and pathophysiology. The importance of the RV in different cardiac disease is now unquestionable and the current evidence emphasizes the forgotten interdependent relationship between the right and the left heart and the pivotal role of RV dysfunction in determining functional performance and outcomes in many cardiac disorders and particularly in cardiomyopathies. The purpose of this review is to summarize the current evidence about the diagnostic and prognostic value of the right heart in the “left-sided” cardiomyopathies, highlighting the relevance to assess RV size and function by multimodality imaging techniques in order to obtain useful information for a proper diagnostic workup and for the prognosis.     

磁共振成像在心内膜心肌活检阴性心肌炎患者中的诊断价值:回顾性病例系列研究

目的分析临床诊断心肌炎但心内膜心肌活检(EMB)阴性患者的心脏磁共振(CMR)表现,探讨CMR在此类患者中的诊断价值。方法该研究为回顾性分析。纳入符合2013年欧洲心脏病学会(ESC)心肌炎临床诊断标准,但EMB阴性的患者14例。所有患者均行CMR检查,通过黑血序列、电影序列、T2W-STIR序列及钆对比剂延迟增强(LGE)序列,评价心脏的形态学、功能学、组织学改变。结果该研究共纳入14例符合临床诊断标准的心肌炎患者,男10例,女4例,年龄为(25.6±13.2)岁,症状发作至行CMR检查时间间隔为21(13,60)d,症状发作距离EMB检查时间为19(9,40)d。CMR阳性患者13例,表现为心肌水肿、纤维化、射血分数减低、心包积液或心腔增大等。14例患者中共9例患者存在CMR形态和/或功能异常,其中左心房增大1例,左心室增大1例,右心室增大3例,左心室收缩末期容积指数超过正常范围4例,左心室射血分数<50%3例,右心室射血分数<40%5例,心包积液深度>3 mm 3例。14例患者中,有11例存在组织学改变,其中6例患者的T2比值≥2;LGE阳性10例(10/14),最常见的强化模式为左心室侧壁心外膜下和/或室间隔肌壁间(9例),另外左心室壁广泛心内膜下强化2例,无右心室壁强化。结论CMR能够在体评估心脏形态、功能及组织学改变,对于EMB阴性的心肌炎患者,CMR具有良好的补充诊断价值。     

Right Ventricular Cardiac Myxoma

BACKGROUND: Cardiac myxomas are the most common type of cardiac tumors. About 75-85% of cardiac myxomas originate in the left atrium, 15-20% in the right atrium. Most myxomas arise from the interatrial septum adjacent to the fossa ovalis. Only 3-4% are found in the left and right ventricle each. Although myxomas are histologically benign, they may be fatal because of their strategic position. CASE STUDY: The authors report on a 24-year-old patient with stabbing thoracic pain and dyspnea due to pulmonary thromboembolism that was caused by an atypically localized myxoma at the right ventricular apex originating from the interventricular septum. The diagnosis was based on cardiac magnetic resonance (CMR) imaging. Superior to echocardiography, CMR could strengthen the diagnostic accuracy by additional information on tissue characterization using different imaging sequences. Typically for cardiac myxomas, contrast enhancement was moderate and delayed enhancement was found in the outer circumferential tumor margins only. CONCLUSION: High spatial resolution and multiplane imaging combined with different acquisition patterns of CMR achieve a global view of the heart that seems to be useful for diagnosing cardiac tumorous masses.     

Echocardiographic assessment of the right ventricle in the current era: Application in clinical practice

The right ventricle has unique structural and functional characteristics. It is now well recognized that the so‐called forgotten ventricle is a key player in cardiovascular physiology. Furthermore, there is accumulating evidence that demonstrates right ventricular dysfunction as an important marker of morbidity and mortality in several commonly encountered clinical situations such as heart failure, pulmonary hypertension, pulmonary embolism, right ventricular myocardial infarction, and adult congenital heart disease. In contrast to the left ventricle, echocardiographic assessment of right ventricular function is more challenging as volume estimations are not possible without the use of three‐dimensional (3D) echocardiography. Guidelines on chamber quantification provide a standardized approach to assessment of the right ventricle. The technique and limitations of each of the parameters for RV size and function need to be fully understood. In this era of multimodality imaging, echocardiography continues to remain a useful tool for the initial assessment and follow‐up of patients with right heart pathology. Several novel approaches such as 3D and strain imaging of the right ventricle have expanded the usefulness of this indispensable modality.     

Computed tomography and cardiac magnetic resonance imaging in pulmonary hypertension

Recent advances in imaging technology have allowed for better temporal and spatial resolution in cardiovascular imaging. The idea of a “one-stop shop” for anatomical and functional cardiopulmonary and vascular assessment in patients with pulmonary hypertension is very appealing since diagnostic, prognostic, and therapeutic response can be measured. Modalities, such as computed tomography (CT) and cardiac magnetic resonance (CMR), are better suited to image the right heart and associated structures in multiple projections allowing for three-dimensional data sets and image reconstruction. This review will focus on the use of CT and CMR in the assessment of the right ventricle and pulmonary structures as they relate to pulmonary vascular disease.     

Real-time, intracardiac, two-dimensional echocardiography: enhanced depth of field with a low-frequency (12.5 mhz) ultrasound catheter

Advances in catheter-based ultrasound imaging technology allow for a unique opportunity to develop two-dimensional intracardiac echocardiography, an imaging method that could have significant clinical applications. In this study, we evaluated the potential of a new, percutaneous, 9-Fr prototype intracardiac echocardiographic catheter with a 12.5-MHz rotating crystal in 13 dogs. In all dogs, we were able to easily advance the intracardiac echocardiographic catheter into the right and left hearts percutaneously and obtain dynamic images of cardiac structures in various imaging planes. With the intracardiac echocardiographic catheter in the right atrium, the whole chamber could be visualized. Minor manipulation allowed visualization of the right atrium, right ventricle, and tricuspid valve in a two-chamber view; further maneuvering yielded four-chamber views. With advancement of the catheter into the right ventricle and pulmonary artery, the right ventricular cavity, right ventricular outflow tract, and pulmonary artery could be imaged. The intracardiac echocardiographic catheter in the aortic root allowed visualization of the pulmonary artery and its bifurcation, superior portions of the atria, interatrial septum, aortic valve, and the proximal left coronary artery. With the intracardiac echocardiographic catheter in the left ventricle, short-axis images of the whole left ventricle were obtained. Manipulating the catheter tip within the left ventricle, we could visualize the left ventricle, left atrium (LA), and the mitral valve in the long axis. We were also able to visualize and identify experimentally-induced ischemic regional left ventricular dyskinesis (four of of five dogs), aortic valvular tear (five out of five dogs), and pericardial effusion with right atrial collapse (two out of two dogs). Intracardiac echocardiography was not associated with any complications. We conclude that percutaneous, low-frequency intracardiac echocardiography with a 12.5-MHz, 9-Fr catheter yields cardiac images in many imaging planes with a good depth of field, allows identification of valvular, myocardial, and pericardial abnormalities, and has excellent clinical potential in the assessment of many cardiovascular disorders.     

Thallium-201 stress redistribution abnormalities of the right ventricle: A manifestation of proximal right coronary artery stenosis

Thallium imaging in conjunction with electrocardiographic stress testing has become a widely utllized method for evaluating the presence and location of coronary artery disease. The literature has emphasized the appearance of the left ventricle with little mention of the right ventricle. This report presents the initial demonstration of abnormal right ventricular myocardial radionuclide visualization due to right coronary artery stenosis, as exemplified in two patients. In both patients a perfusion defect was documented in the free wall of the right ventricle with early redistribution imaging showing reversibility of these defects. Both patients were found to have proximal stenosis of the right coronary artery at cardiac catheterization. Thereby, the appearance of the free right ventricular wall on thallium imaging may provide useful additional information regarding presence and location of right coronary artery stenosis.     

Usefulness of magnetic resonance imaging for the diagnosis of right ventricular dysplasia in children

Cardiac magnetic resonance (CMR) has been helpful in adults in the diagnosis of arrhythmogenic right ventricular dysplasia. Short of direct surgical observation or autopsy, no gold standard exists. CMR diagnostic criteria include right atrial and ventricular dilation, regional right ventricular (RV) wall motion abnormalities, outflow tract ectasia, and myocardial fatty infiltration. To determine whether adult diagnostic criteria are useful in children referred for CMR for this diagnosis, the images and records of 81 patients (aged 11.5 +/- 5.5 years) over an 8-year period were reviewed. Histories included ventricular tachycardia, palpitations, dilated right ventricle, syncope, near sudden death, or family history of RV dysplasia. Four families were studied with parents who had RV dysplasia diagnosed by surgery, explanted heart, or CMR. CMR imaging included T1-weighted imaging, cine, 1-dimensional RV myocardial tagging, and phase-encoded velocity mapping, and 2 patients underwent delayed-enhancement CMR. Only 1 of the 81 patients met 5 of the criteria. None of the others met >2 of the criteria, and only 2 patients met 1 or 2 criteria. For questionable regional wall motion abnormalities, RV myocardial tagging was helpful. In conclusion, CMR of patients with a history suspicious for the diagnosis of RV dysplasia is a low-yield test in children. This may be due to the evolving nature of the disease, which does not manifest itself from a morphologic or ventricular-function standpoint until later in development. Follow-up studies as patients age may be advantageous.     

成人先天性心脏病合并肺动脉高压患者的心脏磁共振评估

目的 探讨心脏磁共振（cardiac magnetic resonance,CMR）评价先天性心脏病合并肺动脉高压患者心室功能的临床价值.方法 对26例先天性心脏病合并肺动脉高压的患者行CMR检查,分别测量并计算右心室与左心室的短轴缩短率、舒张末期直径、舒张末期容积、收缩末期容积、每搏排血量、射血分数等心功能参数及主动脉、肺动脉直径,同时评价室间隔运动、心肌延时强化.采用配对样本t检验比较左、右心室功能参数,采用两个独立样本t检验比较室间隔运动正常组和异常组的右心功能情况,采用卡方检验比较室间隔运动异常与心肌延时强化的关联.结果 右心室舒张末期直径、舒张末期容积、收缩末期容积均显著高于左心室,差异有统计学意义（P＜0.05）;右心室短轴缩短率、射血分数均显著低于左心室,差异有统计学意义（P＜0.05）.26例患者中,14例室间隔运动异常,14例出现心肌延时强化.室间隔运动异常组心肌延时强化出现比例明显高于室间隔运动正常组,差异有统计学意义（P＜0.05）.同时,室间隔运动异常组的右心室舒张末期直径、舒张末期容积均显著高于正常组,差异有统计学意义（P＜0.05）;右心室短轴缩短率显著低于正常组,差异有统计学意义（P＜0.05）;射血分数低于正常组,但差异无统计学意义（P=0.08）.结论 合并肺动脉高压的成人先天性心脏病患者右心功能较左心功能差,室间隔运动异常患者的右心功能更差,室间隔运动异常患者出现心肌延时强化比例高.CMR能够提供先天性心脏病合并肺动脉高压患者的左、右心室功能及相关结构信息,对治疗和预后有重要价值.     

Cardiac magnetic resonance imaging for stage B heart failure

Cardiac magnetic resonance imaging (CMR) can play a key role in the assessment and follow-up of patients with stage B heart failure. CMR currently serves as the reference standard for quantifying right and left ventricular size and ejection fraction. Technical advances have also enabled CMR to provide noninvasive tissue characterization and detailed assessments of myocardial performance. Thus, in addition to standard metrics of cardiac structure and function, CMR offers a variety of tools for determining cause, severity, and estimating the prognosis associated with an asymptomatic cardiomyopathy.     

Ischemic heart disease: comprehensive evaluation by cardiovascular magnetic resonance

Considerable technical advances over the past decade have increased the clinical application of cardiovascular magnetic resonance (CMR) imaging. A comprehensive CMR examination can accurately measure left and right ventricular size and function, identify the presence and extent of reversible versus irreversible myocardial injury, and detect inducible ischemia. Streamlined protocols allow such a CMR examination to be a time-efficient diagnostic tool in patients with coronary artery disease. Moreover, edema imaging with T2-weighted CMR allows the detection of acute coronary syndromes. In this review, we present the relevant CMR methods and discuss practical uses of CMR in acute and chronic ischemic heart disease.     

Reversible ischaemia of right ventricle detected by exercise thallium-201 scintigraphy.

Exercise and redistribution thallium-201 imaging is commonly used for the detection and evaluation of left ventricular ischaemia and infarction. The right ventricle is frequently visualised after stress and sometimes on redistribution images. The visualisation of the right ventricle at rest is thought to be abnormal and is suggestive of pressure or volume overload of the right ventricle, either a result of pulmonary hypertension or secondary to left ventricular dysfunction. Using stress and delayed 201Tl imaging we have shown reversible left and right ventricular ischaemia and fixed left ventricular perfusion defects in two patients with multivessel coronary artery disease and left ventricular dyskinesia caused by prior myocardial infarction. Judging by the rarity of this finding as well as taking into consideration 201Tl kinetics, it is suggested that reversible right ventricular ischaemia after exercise may only be detected in patients with coronary artery disease who have severely compromised ventricular function. This finding may have therapeutic and prognostic significance.     

Comparison of left and right atrial volume by echocardiography versus cardiac magnetic resonance imaging using the area-length method

Increased atrial volumes predict adverse cardiovascular events. Accordingly, accurate measurement of atrial size has become increasingly important in clinical practice. The area-length method is commonly used to estimate the volume. Disagreements between atrial volumes using echocardiography and other imaging modalities have been found. It is unclear whether this has resulted from differences in the measurement method or discrepancies among imaging modalities. We compared the right atrial (RA) and left atrial (LA) volume estimates using the area-length method for transthoracic echocardiography and cardiovascular magnetic resonance (CMR) imaging. Patients undergoing echocardiography and CMR imaging within 1 month were identified retrospectively. For both modalities, the RA and LA long-axis dimension and area were measured using standard 2- and 4-chamber views, and the volume was calculated using the area-length method for both atria. The echocardiographic and CMR values were compared using the Bland-Altman method. A total of 85 patients and 18 controls were included in the present study. The atrial volumes estimated using the area-length method were significantly smaller when measured using echocardiography than when measured using CMR imaging (LA volume 35 ± 20 vs 49 ± 30 ml/m2, p <0.001, and RA volume 32 ± 23 vs 43 ± 29 ml/m2, p = 0.012). The mean difference (CMR imaging minus echocardiography) was 14 ± 14 ml/m2 for the LA and 10 ± 16 ml/m2 for the RA volume. Similar results were found in the healthy controls. No significant intra- or interobserver variability was found within each modality. In conclusion, echocardiography consistently underestimated the atrial volumes compared to CMR imaging using the area-length method.     

Nonvolumetric echocardiographic indices of right ventricular systolic function: validation with cardiovascular magnetic resonance and relationship with functional capacity

Purpose: Right ventricular (RV) systolic function as measured by right ventricular ejection fraction (RVEF) has long been recognized as an important predictor of outcome in heart failure patients. The echocardiographic measurement of RV volumes and RVEF is challenging, however, owing to the unique geometry of the right ventricle. Several nonvolumetric echocardiographic indices of RV function have demonstrated prognostic value in heart failure. Comparison studies of these techniques with each other using RVEF as a benchmark are limited, however. Furthermore, the contribution of these various elements of RV function to patient functional status is uncertain. We therefore aimed to: (1) Determine which nonvolumetric echocardiographic index correlates best with RVEF as determined by cardiac magnetic resonance (CMR) imaging (the accepted gold standard measure of RV systolic function) and (2) Ascertain which echocardiographic index best predicts functional capacity. Methods: Eighty‐three subjects (66 with systolic heart failure and 17 healthy controls) underwent CMR, 2D echocardiography, and cardiopulmonary exercise testing for comparison of echocardiographic indices of RV function with CMR RVEF, 6‐minute walk distance and VO_{2 PEAK}. Results: Speckle tracking strain RV strain exhibited the closest association with CMR RV ejection fraction. Indices of RV function demonstrated weak correlation with 6‐minute walk distance, but basal RV strain rate by tissue velocity imaging had good correlation with VO_{2 PEAK}. Conclusion: Strain by speckle tracking echocardiography and strain rate by tissue velocity imaging may offer complementary information in the evaluation of RV contractility and its functional effects. (Echocardiography 2012;29:455‐463)     

Importancia de los hallazgos de la resonancia magnética cardiaca en el diagnóstico de la miocardiopatía arritmogénica del ventrículo izquierdo

Introduction and objectivesLeft dominant arrhythmogenic cardiomyopathy (LDAC) has recently been recognized as falling on the spectrum of arrhythmogenic cardiomyopathy. It is characterized by fibroadipose replacement of the left ventricle. The aim of this study was to describe the most frequent forms of clinical presentation of LDAC, imaging findings, and events at follow-up, highlighting the importance of cardiac magnetic resonance (CMR).MethodsProspective registry of patients with findings compatible with LDAC. CMR image analysis and clinical follow-up was performed. The primary endpoint was the appearance of major adverse cardiovascular events (MACE) during follow-up, defined as sudden cardiac death, sustained ventricular arrhythmias, and heart transplant.ResultsWe included 74 consecutive patients (mean age, 48.6 years; 50 men [67.6%]). The most frequent CMR indications were chest pain with normal coronary angiography, ventricular arrhythmias, and suspicion of cardiomyopathies. The main CMR findings were midwall and/or subepicardial pattern of late gadolinium enhancement (91.9%), fatty epicardial infiltration (83.8%), and left ventricle segmental contractility abnormalities (47.9%). At a mean follow-up of 3.74 years, 24 patients (32.4%) had a MACE (sudden cardiac death 8.1%, sustained ventricular arrhythmias 21.6%, and heart transplant 4.1%). Independent predictors for the appearance for MACE were a CMR study showing severe late gadolinium enhancement, male sex, and practicing sports.ConclusionsCMR is a key tool for diagnosing LDAC. Characteristic findings are subepicardial fatty infiltration and midwall-subepicardial late gadolinium enhancement. The prognosis of this population is poor with a high incidence of sudden cardiac death and ventricular arrhythmias.     

Multimodality Evaluation of the Right Ventricle: An Updated Review

The assessment of the volumes, function, and mechanics of the right ventricle (RV) is very challenging because of the anatomical complexity of the RV. Because RV structure, function, and deformation are very important predictors of cardiovascular morbidity and mortality in patients with heart failure, pulmonary hypertension, congenital heart disease, or arrhythmogenic RV cardiomyopathy, it is of great importance to use an appropriate imaging modality that will provide all necessary information. In everyday clinical practice, 2‐dimensional echocardiography (2DE) represents a method of first choice in RV evaluation. However, cardiac magnetic resonance (CMR) remained the gold standard for RV assessment. The development of new imaging tools, such as 3‐dimensional echocardiography (3DE), provided reliable data, comparable with CMR, and opened a completely new era in RV imaging. So far, 3DE has shown good results in determination of RV volumes and systolic function, and there are indications that it will also provide valuable data about 3‐dimensional RV mechanics, similar to CMR. Two‐dimensional echocardiography–derived strain is currently widely used for the assessment of RV deformation, which has been proven to be a more significant predictor of functional capacity and survival than CMR‐derived RV ejection fraction. The purpose of this review is to summarize currently available data about RV structure, function, and mechanics obtained by different imaging modalities, primarily 2DE and 3DE, and their comparison with CMR and cardiac computed tomography.     

Left Ventricular Diastolic Dysfunction in β-Thalassemia Major with Heart Failure

We studied the clinical, electrocardiographic, echocardiographic, Doppler and T2* cardiac magnetic resonance (CMR) data of all adult β-thalassemia major (β-TM) patients with heart failure (HF) consecutively observed at our referral center of the Sicilian region between 2008 and 2016. There were 16 patients enrolled in the study. Echocardiographic examination showed that only one patient had HF with systolic dysfunction of the left ventricle (HFrEF), whereas the others had HF with preserved systolic function of the left ventricle (HFpEF). Systolic dysfunction of the right ventricle (RV) was observed in 13 cases. Furthermore, 30.0% of the patients presented T2* CMR values consistent with intermediate risk of systolic dysfunction of the left ventricle (LV) due to iron overload, whereas 70.0% had normal values. Typical electrocardiographic abnormalities (wide T wave inversion and low voltages) were observed in 11 out of 16 patients. In conclusion, in the adult β-TM patients with HF recently observed at our center, the predominant form was that with diastolic dysfunction of the LV, and with systolic dysfunction of the RV. Only 30.0% had low values of T2* CMR. Typical electrocardiographic abnormalities were found in 69.0%.     

心脏核磁共振成像技术在肥厚型心肌病中的应用现状及最新进展

Hypertrophic cardiomyopathy(HCM)is the most common genetic cardiomyopathy and the leading cause of sudden death in young people and a major cause of heart failure symptoms at any age.Due to its genetic etiology,there is substantial heterogeneity in the phenotypic expression and clinical course of patients with HCM.Traditionally,two-dimensional echocardiography has been the easiest and reliable technique for establishing a diagnosis of HCM.However,cardiovascular magnetic resonance(CMR)has emerged as a novel,3-dimensional tomographic imaging technique,which provides high spatial and temporal resolution images of the heart (not limited by thoracic or pulmonary parenchyma),in any plane and without ionizing radiation.As a result,CMR is particularly well suited to provide detailed characterization of the HCM phenotype,including a precise assessment of the location and distribution of LV wall thickening(as well as other myocardial structures such as the right ventricle and papillary muscles).In this regard,CMR has been demonstrated to provide a diagnosis of HCM in cases where the echocardiogam was non-diagnostic.Furthermore,CMR provides an accurate assessment of total LV mass which is a more robust marker of hypertrophy,with potential implications for risk stratification.In addition,with the intravenous administration of gadolinium,first-pass perfusion sequences can identify myocardial perfusion abnormalities,while late gadolinium enhancement sequences can identify areas of myocardial fibrosis/scarring.Although the clinical implications of late gadolinium enhancement in HCM are still uncertain this information may,in the near-future,have important implications with regard to identifying HCM patients at high risk of sudden death and progressive heart failure,including evolution into the end-stage phase of HCM.Therefore,at present,CMR provides important information impacting on diagnosis and clinical management strategies in patients with HCM and will likely have an expanding role in the evaluation of patients with this complex disease.     

Multisite stimulation in refractory heart failure.

Since the early nineties, the employment of DDD pacing from a right ventricular site with a short AV delay in patients with severe heart failure has led to considerable conflicting results, so that the real benefit of this method remains to be defined even in selected patients, such as those with first-degree AV block, QRS duration > 140 ms due to left bundle branch block (LBBB), mitral regurgitation time > or = 450 ms and diastolic filling time < or = 200 ms. Indeed, the asynchronous activation induced by pacing the right apex is the most important limitation to the technique, particularly in patients without an LBBB pattern or in those with an incomplete LBBB pattern. Recent studies have also shown that pacing of the right interventricular septum provides no better results than pacing of the right apex, at least in selected patients with no LBBB pattern and no significant mitral regurgitation. Today, it has been suggested that permanent biventricular pacing could be proposed as a feasible and reliable approach to improving ventricular function through the synchronization of the septum and the apex of the left ventricle, particularly in patients with a marked delay in ventricular activation sequence. This technique may be performed by means of transvenous leads inserted through the coronary sinus into the cardiac veins to stimulate both ventricles simultaneously, starting from the right apex and left lateral wall. Consequently, this approach supplies a strong basis for initiating further studies to examine the chronic effects of left ventricular pacing in patients with severe heart failure. We also suggest that the new tissue Doppler imaging techniques could usefully be applied to accurately select candidates to biventricular pacing.