Hypertrophic cardiomyopathy: assessment with MR imaging and multidetector CT

Three-Tesla Magnetic Resonance Imaging Characteristics of Hypertrophic Cardiomyopathy: A Comparison with Several Echocardiography Parameters

Background

Hypertrophic cardiomyopathy (HCM) is a primary cardiac disorder characterized by myocardial hypertrophy without increased afterload. This study set out to describe the cardiac magnetic resonance (CMR) imaging characteristics of HCM and to evaluate correlations of selected CMR parameters with echocardiography.

Methods

This cross-sectional study enrolled 46 patients diagnosed at the Vietnam Heart Institute with HCM and underwent CMR at the Radiology Center, Bach Mai Hospital, from July 2021 to September 2022.

Results

A left ventricular outflow tract (LVOT)/aortic valve (AO) diameter ratio of ≥0.38 on CMR was consistent with an LVOT pressure gradient (PG) of <30 mmHg on echocardiography. The LVOT diameter and the LVOT/AO diameter ratio differed significantly between obstructive and non-obstructive HCM. The predominant phenotypes were diffuse asymmetric HCM (32.6%) and septal HCM (37%), followed by apical HCM (6.5%). Most late gadolinium enhancement (LGE) lesions were observed in the mid-wall of the hypertrophic segments. The mean LGE mass was significantly higher in the obstructive group than in the non-obstructive HCM group (p < 0.05). A strong negative correlation (r = -0.66) was found between the LVOT/AO diameter ratio on the CMR and the LVOT PG via echocardiography. Moreover, echocardiography detected morphologic risk factors for sudden cardiac death (SCD) in 80.4% of patients, whereas the corresponding proportion detected by CMR was 91.3%. Patients with systolic anterior motion (SAM) had a risk for a LVOT/AO diameter ratio <0.38, which was 5.7 times the risk observed in their counterparts without SAM.

Conclusions

The LVOT/AO diameter ratio detected by CMR is a precise index for classifying hemodynamic HCM groups. CMR was better than echocardiography for SCD risk stratification.

Role of Imaging in the Diagnosis, Evaluation, and Management of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is increasingly recognized and may benefit from the recent approval of new, targeted medical therapy. Successful management of HCM is dependent on early and accurate diagnosis. The lack of a definitive diagnostic test, the wide variation in phenotype and the commonness of phenocopy conditions, and the presence of normal or hyperdynamic left ventricular function in most patients makes HCM a condition that is highly dependent on imaging for all aspects of management including, diagnosis, classification, predicting risk of complications, detecting complications, identifying risk for ventricular arrhythmias, evaluating choice of therapy and monitoring therapy, intraprocedural guidance, and screening family members. Although echocardiographic imaging remains the mainstay in the diagnosis and subsequent management of HCM, this disease clearly requires multimethod imaging for various aspects of optimal patient care. Advances in echocardiography hardware and techniques, development and refinement of imaging with computed tomography, magnetic resonance, and nuclear scanning, and the emergence of very focused assessments such as diastology and fibrosis imaging have all advanced the diagnosis and management of HCM. In this review, we discuss the relative utility and evidence support for these imaging approaches to contribute to improve patient outcomes.

Tailored Planning of Surgical Myectomy in Obstructive Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic myocardial disease characterized by abnormal thickening of the myocardium caused by myocardial disarray and interstitial fibrosis. HCM is associated with sudden cardiac-related events, such as ventricular fibrillation, tachycardia, and syncope. Moreover, left ventricular or midcavity obstruction due to the thickened myocardium can result in severe heart failure and mortality in patients with HCM. Surgical myectomy is a standard treatment option for patients with symptomatic obstructive HCM; however, it is a complex procedure that requires careful planning and execution to avoid complications, such as residual flow obstruction, persistent obliteration of the left ventricular cavity in systole, or iatrogenic ventricular septal defects. Therefore, a thorough understanding of the mechanics of HCM and precise evaluation of the location and extent of the hypertrophic myocardium to be removed are crucial for preoperative planning. Multiphase cardiac CT postprocessing is important for preoperative evaluation and planning of surgical myectomy in patients with HCM. In this review, the authors highlight use of multiphase cardiac CT with step-by-step postprocessing methods to simulate successful surgical myectomy. The transaortic surgeon's view on end-diastolic phase images accurately represents the surgical field. Moreover, myocardial segmentation can be used to generate volume-rendered images and three-dimensional printing. CT evaluation can also assist in identifying concurrent abnormalities, such as mitral valve or papillary muscle abnormalities. In addition to CT, other imaging modalities for preoperative evaluation of HCM and postmyectomy evaluation methods are presented. ©RSNA, 2023 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Hypertrophic cardiomyopathy - phenotypic variations beyond wall thickness

Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy (LVH) in the absence of another causal disease. Several morphologic and histologic changes have been described. Given the morbidity and mortality associated with HCM, understanding these anatomic variations is key to interpreting imaging. This is especially important since many patients exhibit these associated findings in the absence of LVH and prompt early detection of these variations may lead to early diagnosis and treatment. This article describes the appearance of morphologic variations seen in HCM beyond myocardial thickening including: papillary muscle and mitral valve variants, myocardial crypts, left ventricular myocardial bands, and dystrophic calcification related to increased wall tension.

Assessment of cardiac dimensions in children diagnosed with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant heart disease, characterized by increased left ventricular wall thickness and abnormal loading conditions. Imaging modalities are the first choice for diagnosis and risk stratification. Although heart dimensions have been characterized widely in HCM adults from cardiac imaging, there is limited information about children affected by HCM. The aim of this study is to evaluate left ventricular function and left heart dimensions in a small population of children diagnosed with HCM.

METHODS

A total of 16 (seven male, nine female) pediatric patients with an average age of 14.0 ± 2.5 years diagnosed with HCM at Great Ormond Street Hospital for Children were included in this study. Cardiac magnetic resonance (CMR) images were used to measure left and right ventricular dimensions, and septal and left ventricular free wall thicknesses in Simpleware ScanIP. The gender groups were compared using student t-test or non-parametric Mann-Whitney U-test depending on the sample distribution.

RESULTS

Differences in heart rate, left ventricular end-diastolic volume and end-diastolic volume index, left ventricular stroke volume and stroke volume index, left ventricular end-systolic long axis length, left ventricular end-systolic long axis length index, left ventricular end-diastolic mid-cavity diameter, left ventricular end-diastolic free wall thickness, left ventricular end-diastolic free wall thickness index, right ventricular end-diastolic long axis length were statistically significant in males and females.

CONCLUSION

Left ventricular wall and intraventricular septal thickness increase affecting left ventricle cavity dimensions and there may be differences in anatomical and physiological parameters in males and females affected by HCM.

Clinical Insights Into Heritable Cardiomyopathies

Cardiomyopathies (CMs) encompass a heterogeneous group of structural and functional abnormalities of the myocardium. The phenotypic characteristics of these myocardial diseases range from silent to symptomatic heart failure, to sudden cardiac death due to malignant tachycardias. These diseases represent a leading cause of cardiovascular morbidity, cardiac transplantation, and death. Since the discovery of the first locus associated with hypertrophic cardiomyopathy 30 years ago, multiple loci and molecular mechanisms have been associated with these cardiomyopathy phenotypes. Conversely, the disparity between the ever-growing landscape of cardiovascular genetics and the lack of awareness in this field noticeably demonstrates the necessity to update training curricula and educational pathways. This review summarizes the current understanding of heritable CMs, including the most common pathogenic gene variants associated with the morpho-functional types of cardiomyopathies: dilated, hypertrophic, arrhythmogenic, non-compaction, and restrictive. Increased understanding of the genetic/phenotypic associations of these heritable diseases would facilitate risk stratification to leveraging appropriate surveillance and management, and it would additionally provide identification of family members at risk of avoidable cardiovascular morbidity and mortality.

Impact of cardiac magnetic resonance on the diagnosis of hypertrophic cardiomyopathy - a 10-year experience with over 1000 patients

Objectives

To assess the value of cardiac MRI in comparison to echocardiography in consecutive patients with previously diagnosed and new suspected hypertrophic cardiomyopathy (HCM).

Methods

All MRI studies of patients with HCM or suspected disease performed at our centre within a 10-year time period were evaluated. Initial diagnoses (echocardiography-based) and final (MRI-based) diagnoses were compared in subgroups, and the discrepancies were recorded.

Results

A total of 1006 subjects with HCM or suspected HCM were identified (61% males, 39% females; median age, 49.1 years; interquartile range, 34.9–60.4). In 12 (2.2%) out of 550 patients with known HCM, MRI indicated a diagnosis other than HCM, including but not limited to the subaortic membrane (n = 1, 8.3%) or mild left ventricular hypertrophy (n = 5, 41.7%). Among all patients with suspected HCM (n = 456), MRI diagnosis was different from HCM in 5.3% (n = 24) of patients. In an additional 20.4% of patients (n = 93), no significant hypertrophy was present. In total, among patients with suspected HCM, MRI led to clear HCM diagnosis in 204 (44.7%) patients. Among patients with a history of uncontrolled hypertension suspected of having HCM, MRI aided in identifying cardiomyopathy in 47.9% of patients. This subgroup contained the largest proportion of patients with an ambiguous diagnosis, namely, 29.6% compared with 13.8% in the remaining groups of patients with suspected HCM (p = 0.0001).

Conclusions

In a small but important group of patients with ultrasound-based HCM, cardiac MRI can diagnose previously unknown conditions and/or refute suspected cardiomyopathy. The diagnostic yield of MRI when compared to echocardiography in patients suspected of having HCM is 44.7%.

Key Points

• Out of 550 patients previously diagnosed with echocardiography but without magnetic resonance imaging (MRI) as having hypertrophic cardiomyopathy (HCM), we diagnosed a different disease in 12 (2.2%) patients using MRI.

• Among patients with suspected HCM based on echocardiography, MRI led to clear HCM diagnosis in 44.7% of patients.

• In patients with a history of uncontrolled hypertension suspected, based on an echocardiogram, of having HCM, MRI aided in identifying cardiomyopathy in 47.9% of patients. This subgroup contained the largest proportion of patients with an ambiguous diagnosis.

Paediatric cardiomyopathies: echocardiographic diagnosis, clinical profile, and demographic characteristics: the experience of a tertiary referral centre for Latin American paediatric cardiology

BACKGROUND

Although multiple studies have been conducted in the adult population, there is a vast knowledge gap regarding the epidemiologic characteristics of cardiomyopathies in the paediatric population. This issue is even more crucial when the precarious situation of medical research in Latin America is considered. Given the potential impact that these disorders could have on Latin American health systems, a comprehensive epidemiologic study regarding the clinical profile and sociodemographic characteristics of these patients will influence the way we approach paediatric cardiomyopathies.

METHODS

An observational retrospective study was conducted at a tertiary referral centre for Colombian and Latin American paediatric cardiology. We analysed all cases of primary cardiomyopathies in children younger than 18 years of age who presented at our institution between 2010 and 2016. Cases of cardiomyopathies were classified according to World Health Organization guidelines.

RESULTS

From a total of 29,533 children who attended our institution during the study period, 89 new cases of primary cardiomyopathies were identified. The median age at diagnosis was 11 years (interquartile range 4-9). Dilated cardiomyopathy accounted for 57.3% (n = 51) of cases; hypertrophic cardiomyopathy, 12.3% (n = 11); restrictive cardiomyopathy, 8.9% (n = 8); non-compacted cardiomyopathy, 7.8% (n = 7); arrhythmogenic ventricular cardiomyopathy, 6.7% (n = 6); and unspecified cardiomyopathy, 6.7% (n = 6). Heart failure was observed in 53.93% of the patients. The overall mortality was 12.36% (n = 11), which included two of eight patients who underwent cardiac transplantation.

Assessment of Left Ventricular Myocardial Diseases with Cardiac Computed Tomography

Rapid advances in cardiac computed tomography (CT) have enabled the characterization of left ventricular (LV) myocardial diseases based on LV anatomical morphology, function, density, and enhancement pattern. Global LV function and regional wall motion can be evaluated using multi-phasic cine CT images. CT myocardial perfusion imaging facilitates the identification of hemodynamically significant coronary artery disease. CT delayed-enhancement imaging is used to detect myocardial scar in myocardial infarction and to measure the extracellular volume fraction in non-ischemic cardiomyopathy. Multi-energy cardiac CT allows the mapping of iodine distribution in the myocardium. This review summarizes the current techniques of cardiac CT for LV myocardial assessment, highlights the key findings in various myocardial diseases, and presents future applications to complement echocardiography and cardiovascular magnetic resonance.

Complete Resolution of Left Ventricular Outflow Tract Obstruction After Spontaneous Mitral Valve Chordal Rupture in a Patient With Hypertrophic Cardiomyopathy

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Spontaneous mitral chordal rupture is a complication in hypertrophic cardiomyopathy (HCM).

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Mitral chordal rupture in HCM causes deterioration in heart failure.

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Symptoms improved when left ventricular outflow tract (LVOT) obstruction disappeared.

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Mitral valve has a role in LVOT obstruction and systolic anterior motion.

Role of Cardiac Computed Tomography in the Diagnosis of Left Ventricular Myocardial Diseases

Multimodality imaging is indicated for the evaluation of left ventricular (LV) myocardial diseases. Cardiac magnetic resonance (CMR) allows morphological and functional assessment of the LV along with soft tissue characterization. Technological advances in cardiac computed tomography (CT) have led to the development of techniques for diagnostic acquisition in LV myocardial disease. Cardiac CT facilitates the characterization of LV myocardial disease based on anatomy, function, and enhancement pattern. LV regional and global functional parameters are evaluated using multi-phasic cine CT images. CT myocardial perfusion facilitates the identification of hemodynamically significant coronary artery stenosis. Cardiac CT with delayed enhancement is used to detect myocardial scarring or fibrosis in myocardial infarction and non-ischemic cardiomyopathy, and for the measurement of extracellular volume fraction in non-ischemic cardiomyopathy. In this review, we review imaging techniques and key imaging features of cardiac CT used for the evaluation of myocardial diseases, along with CMR findings.

Disparities in the Diagnosis of Hypertrophic Obstructive Cardiomyopathy: A Narrative Review of Current Literature

Hypertrophic obstructive cardiomyopathy (HOCM) is a disorder of abnormal thickening of the myocardium that affects 0.2% of the population. HOCM is a frequently implicated cause of sudden cardiac death (SCD) in young athletes. In this manner, this condition has the capacity for tremendous emotional, social, financial, and medical burdens for families and communities across the country. Multiple factors including genetics and hormonal elements are believed to play a role in the development of this cardiomyopathy. HOCM is an autosomal dominant trait with variable expressivity. It is associated with several genetic changes in the myosin heavy chain genes. Current treatment includes optimization of cardiac risk factors and medical management with beta-adrenergic blockade with definitive treatment of surgical intervention to reduce cardiac workload. The demographic most likely to be diagnosed with HOCM based upon clinical registry data is Caucasian boys and men. However, a growing body of data supports increased prevalence in African American populations and percentages equal to, if not higher than, Caucasian males in Hispanic populations. Similarly, males of African American ethnicity that participate in basketball are the most likely demographic to be affected by HOCM based on the data available from the National Collegiate Athletic Association (NCAA). Further, though rates of diagnosis may be up to 1.5 times higher in males than in females, an increasing number of studies demonstrate an increased prevalence of HOCM in females, often presenting with worse symptoms and an increased incidence of disease progression. Similarly, data suggest that age of diagnosis is associated with various prognostic factors including annual mortality. In addition, consideration of the social determinants of health undoubtedly impacts the rate of diagnosis, access to care, and HOCM-related complications in underserved populations. Effective screening including auscultation and electrocardiography (EKG) with confirmatory echocardiography in these communities supports equitable surveillance and management of HOCM.

Clinics in diagnostic imaging (189). Acute phase cardiac sarcoidosis (CS)

A 44-year-old man presented with breathlessness and episodes of palpitations for the last one year. The imaging diagnosis of cardiac sarcoidosis was made based on chest radiography and cardiac magnetic resonance (MR) imaging findings, and was further confirmed by biopsy. Cardiac sarcoidosis is an uncommon entity, yet is potentially fatal with nonspecific clinical manifestations, including sudden cardiac death. Hence, it is important to diagnose and treat this entity at an early stage to improve morbidity and mortality. Cardiac MR imaging plays a pivotal role in facilitating diagnosis and monitoring therapeutic response. We describe the MR imaging features of cardiac sarcoidosis and discuss imaging features of other cardiomyopathies that may mimic cardiac sarcoidosis.

Mechanical dyssynchrony and diastolic dysfunction are common in LVH: a pilot correlation study using Doppler echocardiography and CZT gated-SPECT MPI

Hypertrophic cardiomyopathy (HCM) is an often under-diagnosed cause of left ventricular hypertrophy (LVH). It affects 1/500 of the population, is the most commonly inherited cardiovascular disorder, and can present in apical, concentric, or septal forms. Although most patients are asymptomatic, sudden cardiac death can be the initial presentation of HCM. By retrospectively enrolling patients suspected of having three different types of HCM in the absence of epicardial coronary stenosis, we aimed to examine systolic and diastolic dysfunction and perfusion abnormalities using both Doppler echocardiography and state-of-the-art gated single-photon emission computerized tomography (SPECT) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera and thallium-201. Both regional perfusion and gated SPECT parameters were collected in addition to diastolic parameters from Doppler echocardiography. The results showed that mild ischemia was common in patients suspected of having HCM, with a mean summed stress score of 4.7 ± 4.9 (score 0–4 in 17-segment model). The patients with HCM were associated with discernible left ventricular mechanical dyssynchrony, especially those with the apical form. In addition, diastolic dysfunction was prevalent and early to late ventricular filling velocity ratios were significantly different between groups. By combining gated-MPI and Doppler data, the trivial functional changes in HCM may be identified.

Imaging in Congenital and Hereditary Abnormalities of the Interventricular Septum: Clinical Anatomy and Diagnostic Clues

Early identification of congenital heart diseases, specifically those affecting the structural integrity and function of the interventricular septum, in childhood is important toward decreasing the morbidity and mortality of those affected. We review the pertinent clinical and imaging manifestations for those with ventricular septal defects, ventricular septal aneurysms, tetralogy of Fallot, and hypertrophic (obstructive) cardiomyopathy, in addition to discussing first-line imaging studies, including echocardiography, and indications for advanced imaging.

Sudden cardiac arrest in hypertrophic cardiomyopathy with dynamic cavity obstruction: The case for a decatecholaminisation strategy

Catecholamines are entrenched in the management of shock states. A paradigm shift has pervaded the critical care arena in recent years acknowledging their propensity to cause harm and fuel a 'death-spiral'. We present the case of a 21-year-old male following a witnessed out-of-hospital cardiac arrest who received high-quality cardiopulmonary resuscitation and standard advanced life support for refractory ventricular fibrillation until return of spontaneous circulation after 70 min. Early post-admission echocardiography revealed severe diffuse sub-basal left ventricular hypertrophy with dynamic mid-cavity obstruction and akinetic apical pouching. Within this context, a decatecholaminised strategy comprising a beta-blocker was used to augment the left ventricular end-diastolic volume and attain cardiovascular stability.

Myocardial T2 Mapping in Patients With Hypertrophic Cardiomyopathy

OBJECTIVE

The aim of this study was to evaluate the usefulness of T2 mapping for detecting myocardial injuries in patients with hypertrophic cardiomyopathy (HCM).

METHODS

Twenty-one HCM patients and 7 healthy volunteers were examined. The T2 values were measured at hyperintense areas (high-T2 areas) identified with T2 mapping, at late gadolinium enhancement (LGE) areas, and in nullified myocardium of the HCM patients. The associations between T2 values and laboratory data or LGE areas were assessed.

RESULTS

High-T2 areas had significantly greater T2 values than LGE areas (P < 0.05) and nullified areas (P < 0.01) of HCM and normal myocardium (P < 0.01). The presence of high-T2 areas was associated with an increase in troponin T levels (P = 0.02), and T2 values correlated with the levels of brain natriuretic peptide (P = 0.036, r = 0.86).

CONCLUSIONS

T2 mapping identified myocardial injuries suggested by the laboratory data in HCM.

Analysis of three-dimensional endocardial and epicardial strains from cardiac magnetic resonance in healthy subjects and patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic disease that leads to left ventricle (LV) hypertrophy with or without the presence of LV outflow tract obstruction. The aim of this study was to find an easy and useful indicator based on cardiac magnetic resonance (CMR) images for control subjects and patients with and without obstruction. CMR scans were performed for 19 control subjects and 19 HCM patients. Endocardial strain was defined as [Formula: see text], with [Formula: see text] being the length of endocardium at end-diastole (end-systole); similarly for epicardial strain ([Formula: see text]). The strains were evaluated in cine CMR two-, three- and four-chamber views. Six atrioventricular junction (AVJ) points from three CMR views were semi-automatically tracked. The peak systolic velocity (Sm1), peak early diastolic velocity and late diastolic velocity (Em, Am) were extracted and analysed. Compared with control subjects, HCM patients had significantly smaller three-dimensional strains and AVJ motion incorporating measurements from three long-axis views (all P < 0.05). Moreover, ROC analysis found that three-dimensional global epicardial strain <17.2% had the best sensitivity 94.4% and specificity 94.7% to differentiate HCM from control (AUC = 0.97). Therefore, three-dimensional endocardial and epicardial strains provide an easy and effective approach to manage and triage hypertrophic cardiomyopathy patients.

Hypertrophic Cardiomyopathy from A to Z: Genetics, Pathophysiology, Imaging, and Management

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of diseases related to sarcomere gene mutations exhibiting heterogeneous phenotypes with an autosomal dominant mendelian pattern of inheritance. The disorder is characterized by diverse phenotypic expressions and variable natural progression, which may range from dyspnea and/or syncope to sudden cardiac death. It is found across all racial groups and is associated with left ventricular hypertrophy in the absence of another systemic or cardiac disease. The management of HCM is based on a thorough understanding of the underlying morphology, pathophysiology, and clinical course. Imaging findings of HCM mirror the variable expressivity and penetrance heterogeneity, with the added advantage of diagnosis even in cases where a specific mutation may not yet be found. The diagnostic information obtained from imaging varies depending on the specific stage of HCM-phenotype manifestation, including the prehypertrophic, hypertrophic, and later stages of adverse remodeling into the burned-out phase of overt heart failure. However, subtle or obvious, these imaging findings become critical components in diagnosis, management, and follow-up of HCM patients. Although diagnosis of HCM traditionally relies on clinical assessment and transthoracic echocardiography, recent studies have demonstrated increased utility of multidetector computed tomography (CT) and particularly cardiac magnetic resonance (MR) imaging in diagnosis, phenotype differentiation, therapeutic planning, and prognostication. In this article, we provide an overview of the genetics, pathophysiology, and clinical manifestations of HCM, with the spectrum of imaging findings at MR imaging and CT and their contribution in diagnosis, risk stratification, and therapy.

Cardiac Magnetic Resonance and Computed Tomography in Hypertrophic Cardiomyopathy: an Update

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease and represents the main cause of sudden death in young patients. Cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) are noninvasive imaging methods with high sensitivity and specificity, useful for the establishment of diagnosis and prognosis of HCM, and for the screening of patients with subclinical phenotypes. The improvement of image analysis by CMR and CCT offers the potential to promote interventions aiming at stopping the natural course of the disease. This study aims to describe the role of RCM and CCT in the diagnosis and prognosis of HCM, and how these methods can be used in the management of these patients.

Contrast-enhanced Steady-state Free Precession in the Assessment of Hypertrophic Obstructive Cardiomyopathy after Alcohol Septal Ablation

PURPOSE

We evaluated the feasibility of contrast-enhanced steady-state free precession (ceSSFP) in the assessment of myocardial injury and obstruction of the left ventricular outflow tract (LVOT) in patients with hypertrophic obstructive cardiomyopathy (HOCM) after alcohol septal ablation (ASA).

METHODS

Twelve patients with HOCM underwent 16 magnetic resonance (MR) examinations following ASA. Precontrast SSFP, ceSSFP and late gadolinium enhancement (LGE) imaging were performed with a 1.5-tesla imager. ceSSFP was performed 3 to 7 min after gadolinium injection. We visually and quantitatively evaluated the signal patterns of the myocardium after ASA on SSFP and LGE MR imaging. We observed the LVOT using ceSSFP in the 3-chamber view.

RESULTS

We could visualize ASA-induced myocardial infarction (MI) in all 16 studies by LGE and ceSSFP but in only 6 studies (37.5%) by precontrast SSFP. Contrast was higher between MI and remote myocardium with LGE than ceSSFP (P < 0.01). ASA-induced hypointense regions were well visualized by the 2 sequences after contrast in the 7 patients who underwent MR imaging within 7 weeks of ASA and in a few patients after 80 weeks from ASA. The ceSSFP allowed comparable visualization of the jet flow crossing the LVOT to that derived from echocardiographic data.

CONCLUSION

Contrast-enhanced steady-state free precession allows assessment of myocardial injury as well as of the left ventricular outflow tract after alcohol septal ablation in a single scan without penalty in scan time and cine imaging contrast.

MR Imaging in Hypertrophic Cardiomyopathy: From Magnet to Bedside

Hypertrophic cardiomyopathy ( HCM hypertrophic cardiomyopathy ), the most common genetically transmitted cardiac disorder, has been the focus of extensive research over the past 50 years. HCM hypertrophic cardiomyopathy is a multifaceted disease with highly heterogeneous genetic background, phenotypic expression, clinical presentation, and long-term outcome. Though most patients have an indolent course with a life expectancy comparable to that of the general population, early diagnosis and accurate risk profiling are essential to identify the sizeable subset at increased risk of sudden cardiac death or disease progression and heart failure-related complications, requiring aggressive management options. Imaging has a central role in the diagnosis and prognostic assessment of HCM hypertrophic cardiomyopathy patients, as well as screening of potentially affected family members. In this context, magnetic resonance (MR) imaging has recently emerged as an ideal complement to transthoracic echocardiography. Its multiparametric approach, fusing spatial, contrast, and temporal resolution, provides the clinician with detailed characterization of the HCM hypertrophic cardiomyopathy phenotype and assessment of its functional consequences including causes and site of dynamic obstruction, presence and extent of myocardial perfusion abnormalities, and fibrosis. Moreover, MR is key in differentiating HCM hypertrophic cardiomyopathy from "phenocopies"-that is, hearts with similar morphology but profoundly different etiology, such as amyloid or Anderson-Fabry disease. Long term, the incremental information provided by MR is relevant to planning of septal reduction therapies, identification of the early stages of end-stage progression, and stratification of arrhythmic risk. The aim of this review is to depict the increasingly important role of MR imaging in relation to the complexity of HCM hypertrophic cardiomyopathy , highlighting its role in clinical decision making.

Magnetic Resonance Imaging of Hypertrophic Cardiomyopathy: Beyond Left Ventricular Wall Thickness

During the past decade, cardiac magnetic resonance has gained increasing popularity in the diagnosis of hypertrophic cardiomyopathy because of its greater accuracy and better characterization of cardiac morphology compared with other imaging modalities. In this pictorial essay, a global clinical portrait of hypertrophic cardiomyopathy will be drawn. The various radiologic findings associated with each variant of hypertrophic cardiomyopathy, and the clinical edge offered by cardiac magnetic resonance will be discussed.

Congenital and hereditary causes of sudden cardiac death in young adults: diagnosis, differential diagnosis, and risk stratification

Sudden cardiac death is defined as death from unexpected circulatory arrest-usually a result of cardiac arrhythmia-that occurs within 1 hour of the onset of symptoms. Proper and timely identification of individuals at risk for sudden cardiac death and the diagnosis of its predisposing conditions are vital. A careful history and physical examination, in addition to electrocardiography and cardiac imaging, are essential to identify conditions associated with sudden cardiac death. Among young adults (18-35 years), sudden cardiac death most commonly results from a previously undiagnosed congenital or hereditary condition, such as coronary artery anomalies and inherited cardiomyopathies (eg, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy [ARVC], dilated cardiomyopathy, and noncompaction cardiomyopathy). Overall, the most common causes of sudden cardiac death in young adults are, in descending order of frequency, hypertrophic cardiomyopathy, coronary artery anomalies with an interarterial or intramural course, and ARVC. Often, sudden cardiac death is precipitated by ventricular tachycardia or fibrillation and may be prevented with an implantable cardioverter defibrillator (ICD). Risk stratification to determine the need for an ICD is challenging and involves imaging, particularly echocardiography and cardiac magnetic resonance (MR) imaging. Coronary artery anomalies, a diverse group of congenital disorders with a variable manifestation, may be depicted at coronary computed tomographic angiography or MR angiography. A thorough understanding of clinical risk stratification, imaging features, and complementary diagnostic tools for the evaluation of cardiac disorders that may lead to sudden cardiac death is essential to effectively use imaging to guide diagnosis and therapy.

Magnetic resonance imaging for hypertrophic cardiomyopathy update

OBJECTIVES

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the myocardium. Although many patients remain asymptomatic, sudden cardiac death could be the first manifestation of HCM. Magnetic resonance imaging (MRI) plays an important role in the diagnosis and management of this disease.

METHODS

The epidemiology, pathophysiology, and diagnosis of HCM will be briefly reviewed. This is followed by a discussion on the role of cardiac MRI, recommended protocol, typical imaging findings of HCM, and advanced MRI techniques.

CONCLUSIONS

Although MRI is not intended to be a first-line tool for the assessment of HCM, MRI does provide valuable information to aid the management of patients either at risk of or diagnosed with HCM.

Population-based studies of myocardial hypertrophy: high resolution cardiovascular magnetic resonance atlases improve statistical power

BACKGROUND

Cardiac phenotypes, such as left ventricular (LV) mass, demonstrate high heritability although most genes associated with these complex traits remain unidentified. Genome-wide association studies (GWAS) have relied on conventional 2D cardiovascular magnetic resonance (CMR) as the gold-standard for phenotyping. However this technique is insensitive to the regional variations in wall thickness which are often associated with left ventricular hypertrophy and require large cohorts to reach significance. Here we test whether automated cardiac phenotyping using high spatial resolution CMR atlases can achieve improved precision for mapping wall thickness in healthy populations and whether smaller sample sizes are required compared to conventional methods.

METHODS

LV short-axis cine images were acquired in 138 healthy volunteers using standard 2D imaging and 3D high spatial resolution CMR. A multi-atlas technique was used to segment and co-register each image. The agreement between methods for end-diastolic volume and mass was made using Bland-Altman analysis in 20 subjects. The 3D and 2D segmentations of the LV were compared to manual labeling by the proportion of concordant voxels (Dice coefficient) and the distances separating corresponding points. Parametric and nonparametric data were analysed with paired t-tests and Wilcoxon signed-rank test respectively. Voxelwise power calculations used the interstudy variances of wall thickness.

RESULTS

The 3D volumetric measurements showed no bias compared to 2D imaging. The segmented 3D images were more accurate than 2D images for defining the epicardium (Dice: 0.95 vs 0.93, P<0.001; mean error 1.3 mm vs 2.2 mm, P<0.001) and endocardium (Dice 0.95 vs 0.93, P<0.001; mean error 1.1 mm vs 2.0 mm, P<0.001). The 3D technique resulted in significant differences in wall thickness assessment at the base, septum and apex of the LV compared to 2D (P<0.001). Fewer subjects were required for 3D imaging to detect a 1 mm difference in wall thickness (72 vs 56, P<0.001).

CONCLUSIONS

High spatial resolution CMR with automated phenotyping provides greater power for mapping wall thickness than conventional 2D imaging and enables a reduction in the sample size required for studies of environmental and genetic determinants of LV wall thickness.

ECG-gated cardiac MDCT for detection of systolic anterior motion of mitral valve

OBJECTIVES

Evaluating ECG-gated cardiac MDCT detection of systolic anterior motion of the mitral valve, in comparison to trans-thoracic echocardiography as a gold standard.

MATERIALS AND METHODS

Study group included 83 consecutive patients (57 men; average age 56.1 years) evaluated with both retrospective ECG-gated cardiac MDCT and trans-thoracic echocardiography within an interval of 30 days. ECG-gated cardiac MDCT imaging was performed with retrospective ECG- gating using 64-slice and 128-slice CT scanners with an inherent temporal resolution range of 75-165 ms. MDCT's and trans- thoracic echocardiograms were retrospectively and independently evaluated by experienced radiologist and cardiologist respectively, for presence of systolic anterior motion of the mitral valve.

RESULTS

7 patients (8.4%) were found to have systolic anterior motion by trans-thoracic echocardiography, from which 6 were found to have systolic anterior motion by ECG-gated cardiac MDCT. Of the 76 patients without systolic anterior motion on trans-thoracic echocardiography, all were correctly identified using ECG-gated cardiac MDCT. The sensitivity, specificity, positive and negative predictive values and accuracy of ECG-gated cardiac MDCT in identifying systolic anterior motion of the mitral valve were 85.7% (6/7), 100% (76/76), 100% (6/6), 98.7% (76/77) and 98.8% (82/83), respectively.

CONCLUSION

ECG-gated cardiac MDCT is comparable to trans-thoracic echocardiography in detecting systolic anterior motion of the mitral valve.

[Magnetic resonance imaging of hypertrophic cardiomyopathy : evaluation of diastolic function]

Hypertrophic cardiomyopathy (HCM) has a prevalence of approximately 0.2% and is clinically asymptomatic in many patients or presents with unspecific symptoms. This explains the importance of imaging for the diagnosis of HCM as well as for the assessment of the clinical course. The definitive finding in HCM is myocardial hypertrophy with thickening of the ventricular wall ≥ 15 mm. While echocardiography is an excellent screening tool magnetic resonance imaging (MRI) allows a comprehensive analysis of the heart in HCM. This includes a detailed analysis of the distribution and extent of myocardial hypertrophy, a thorough evaluation of systolic and diastolic cardiac function, the assessment of the presence and extent of dynamic outflow tract obstruction as well as the description of the systolic anterior motion (SAM) phenomenon of the mitral valve with secondary mitral insufficiency. When contrast material is administered, additional information about myocardial perfusion as well as the presence and extent of myocardial fibrosis can be obtained. This study compared systolic functional parameters as well as end systolic and end diastolic wall thickness of patients with and without diastolic dysfunction.

Hypertrophic cardiomyopathy complicated by pulmonary edema in the postpartum period

We report the case of a 42-year-old patient with hypertrophic cardiomyopathy (HCM) who presented to the emergency department with severe shortness of breath one week following uneventful cesarean delivery. Thoracic CT ruled out pulmonary embolus and confirmed pulmonary edema. Asymmetric interventricular septal thickening was clearly identified, demonstrating that the heart may be evaluated even on a non-ECG gated study. Acute pulmonary edema in the postpartum period is an unusual clinical presentation of HCM.

Sudden cardiac death in young athletes: preparticipation screening for underlying cardiovascular abnormalities and approaches to prevention

The study of sudden cardiac death (SCD) in athletes has received more interest in the medical and lay press over the past few years. Professional athletes represent ideals of fitness and health, and the sudden death of prominent athletes can come as a shock. Underlying occult cardiovascular disorders are the most common cause of SCD in athletes. Unfortunately, because these disorders rarely present clinically, their initial manifestation is often a fatal event. Due to this, much attention has turned to both primary and secondary prevention. Primary prevention includes preparticipation screening and secondary prevention includes having automatic external defibrillators available at sporting events. This article summarizes the most common causes of athletic-related cardiac arrest and evaluates the screening methods used to screen for these conditions. The general sentiment is that we need to more effectively identify athletes who are at risk for SCD, but how to do so using an efficient screening system and in a cost-effective manner have not been determined.

[Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging]

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.

Clinical indications for cardiac computed tomography. From the Working Group of the Cardiac Radiology Section of the Italian Society of Medical Radiology (SIRM)

Cardiac computed tomography (CCT) has grown as a useful means in different clinical contexts. Technological development has progressively extended the indications for CCT while reducing the required radiation dose. Even today there is little documentation from the main international scientific societies describing the proper use and clinical indications of CCT; in particular, there are no complete guidelines. This document reflects the position of the Working Group of the Cardiac Radiology Section of the Italian Society of Radiology concerning the indications for CCT.

MRI classification of asymmetric septal hypertrophic cardiomyopathy and its relation to the presence of risk factors

Asymmetric septal hypertrophic cardiomyopathy (ASH) is the common phenotype of hypertrophic cardiomyopathy (HCM). We sought to classify ASH using magnetic resonance imaging (MRI) and to determine whether the MRI classification of ASH is related to the presence of risk factors for HCM. Ninety-three patients with ASH underwent cine and delayed-enhancement MRI. The ASH was classified morphologically using cine MRI at end-diastole. We evaluated the association between the MRI findings and the presence of risk factors in the ASH. The ASH was classified into three subtypes by MRI: contiguous subtype showing various clinical and MRI features (57%), sigmoid subtype (29%) with fewer risk factors, and reverse-curve subtype (14%) in younger patients with the larger myocardial mass and delayed-enhancement, which were significantly related to the risk factors. MRI was used to classify ASH into three subtypes, which might be related to the presence of risk factors.

MR Imaging of Nonischemic Cardiomyopathy

Cardiac magnetic resonance (CMR) imaging plays an important role in the distinction between ischemic and nonischemic cardiomyopathy. It does so principally by its excellent soft-tissue contrast and its ability to detect scar tissue. The distribution of scar tissue not only allows the diagnosis of coronary artery disease in a failing heart but also the type of nonischemic cardiomyopathy. The incorporation of CMR imaging early in the diagnostic cascade of a patient with heart failure of unknown cause can potentially avoid a cardiac catheterization.

Left ventricular apical diseases

There are many disorders that may involve the left ventricular (LV) apex; however, they are sometimes difficult to differentiate. In this setting cardiac imaging methods can provide the clue to obtaining the diagnosis. The purpose of this review is to illustrate the spectrum of diseases that most frequently affect the apex of the LV including Tako-Tsubo cardiomyopathy, LV aneurysms and pseudoaneurysms, apical diverticula, apical ventricular remodelling, apical hypertrophic cardiomyopathy, LV non-compaction, arrhythmogenic right ventricular dysplasia with LV involvement and LV false tendons, with an emphasis on the diagnostic criteria and imaging features.