Detection of apical hypertrophic cardiomyopathy by cardiovascular magnetic resonance in patients with non-diagnostic echocardiography

[Myocardial regional thickness in patients with and without cardiomyopathy assessed by cardiac magnetic resonance]

OBJECTIVE

To explore regional differences in myocardial wall thickness (WT) among the most prevalent cardiomyopathies and in individuals without structural heart disease using cardiac magnetic resonance.

METHODS

Patients older than 18 years referred to cardiac magnetic resonance during the period between January 2014 and September 2014, with a diagnosis of hypertrophic cardiomyopathy, idiopathic dilated cardiomyopathy, ischemic cardiomyopathy, and myocarditis were retrospectively selected from our database.

RESULTS

One hundred twenty patients patients were included. The control group had an average WT of 5.9±1.1mm, with a WT index of 2.9±0.8. Significantly lower mean WT in the apical segments were identified in both the control group (basal 6.7±1.3 vs. mid 6.0±1.3 vs. apical 4.6±1.0mm, P<.0001) and in all evaluated cardiomyopathies (hypertrophic cardiomyopathy: basal 10.5±2.4 vs. mid 10.8±2.7 vs. apical 7.3±3.3mm, P<.0001; idiopathic dilated cardiomyopathy: basal 7.7±1.7 vs. mid 7.6±1.3 vs. apical 5.4±1.3mm, P<.0001; ischemic cardiomyopathy: basal 7.4±1.7 vs. mid 7.5±1.9 vs. apical 5.5±1.8mm, P<.0001; myocarditis: basal 7.1±1.5 vs. mid 6.4±1.1 vs. apical 5.1±0.8, P<.0001). Significant gender differences were also evident regarding the mean WT both in the control group (male 6.5±2.1 vs. female 5.2±1.7mm, P<.0001), as in hypertrophic cardiomyopathy (10.5±5.3 vs. 8.5±5.7mm, P<.0001) and myocarditis (6.6±2.0 vs. 5.2±1.6mm, P<.0001).

CONCLUSION

We found a relatively high prevalence of segments commonly deemed thinned among patients without structural heart disease. We also observed a marked asymmetry and longitudinal gradient in wall thickness both in controls and in the various cardiomyopathies evaluated.

Distribution and Clinical Significance of High Signal Intensity of the Myocardium on T2-Weighted Images in 2 Phenotypes of Hypertrophic Cardiomyopathy

OBJECTIVE

The aim of this study was to evaluate distribution and clinical significance of high signal intensity of the myocardium on T2-weighted images (T2-HI) in 2 phenotypes of hypertrophic cardiomyopathy (HCM).

METHODS

Thirty-six patients with asymmetrical septal HCM (ASH) and 18 patients with apical HCM (APH) and their 864 myocardial segments were investigated. The distribution of T2-HI was compared with that of late gadolinium enhancement (LGE), and the relationships between T2-HI and clinical risk markers were evaluated. T2 values of the T2-HI were estimated with T2 mapping.

RESULTS

The T2-HI was observed in 18 segments (3.1%) in 13 patients with ASH (36.1%) and in 12 segments (4.2%) in 8 patients with APH (44.4%). It was often localized outside LGE. The presence of T2-HI was related to syncope in ASH (P = 0.016). Furthermore, it had higher T2 values (61.1 milliseconds) than the reference myocardium (47.3 milliseconds).

CONCLUSIONS

High signal intensity of the myocardium on T2-weighted images often locates outside LGE and reflects myocardial damage, which is related to syncope in ASH.

The role of cardiovascular magnetic resonance in sudden death risk stratification in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden death in young patients, but current risk stratification strategies do not identify all patients at risk. Contrast-enhanced cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) can identify areas of abnormal myocardial substrate comprising fibrosis, the structural nidus for potentially life-threatening ventricular arrhythmias. More recently, follow-up studies have demonstrated a strong relationship between extent of LGE in patients with HCM and increased risk of adverse disease-related events, including sudden death.

Apical Hypertrophic Cardiomyopathy Among Non-Asians: A Case Series and Review of the Literature

Apical hypertrophic cardiomyopathy (AHCM) has been rarely described in the Western world. More recently, improved sensitivity of diagnostic modalities and increased diagnostic awareness have increased detection rates, suggesting that the prevalence outside of Asia may have been previously understated. Hallmark features of AHCM include deeply negative, “giant” T-wave inversions on electrocardiography and a “spade-like” configuration of the left ventricle on ventriculography. We present two cases of AHCM, one in an African-American female and another in a Caucasian male.

A Striking Coronary Artery Pattern in a Grown-Up Congenital Heart Disease Patient

Left ventricular noncompaction (LVNC) is a myocardial disorder probably due to the arrest of normal embryogenesis of the left ventricle. It could be isolated or associated with other extracardiac and cardiac abnormalities, including coronary artery anomalies. Despite the continuous improvement of imaging resolution quality, this cardiomyopathy still remains frequently misdiagnosed, especially if associated with other heart diseases. We report a case of LVNC association with both malposition of the great arteries and a very original coronary artery pattern.

The multi-modality cardiac imaging approach to the Athlete's heart: an expert consensus of the European Association of Cardiovascular Imaging

The term 'athlete's heart' refers to a clinical picture characterized by a slow heart rate and enlargement of the heart. A multi-modality imaging approach to the athlete's heart aims to differentiate physiological changes due to intensive training in the athlete's heart from serious cardiac diseases with similar morphological features. Imaging assessment of the athlete's heart should begin with a thorough echocardiographic examination.Left ventricular (LV) wall thickness by echocardiography can contribute to the distinction between athlete's LV hypertrophy and hypertrophic cardiomyopathy (HCM). LV end-diastolic diameter becomes larger (>55 mm) than the normal limits only in end-stage HCM patients when the LV ejection fraction is <50%. Patients with HCM also show early impairment of LV diastolic function, whereas athletes have normal diastolic function.When echocardiography cannot provide a clear differential diagnosis, cardiac magnetic resonance (CMR) imaging should be performed.With CMR, accurate morphological and functional assessment can be made. Tissue characterization by late gadolinium enhancement may show a distinctive, non-ischaemic pattern in HCM and a variety of other myocardial conditions such as idiopathic dilated cardiomyopathy or myocarditis. The work-up of athletes with suspected coronary artery disease should start with an exercise ECG. In athletes with inconclusive exercise ECG results, exercise stress echocardiography should be considered. Nuclear cardiology techniques, coronary cardiac tomography (CCT) and/or CMR may be performed in selected cases. Owing to radiation exposure and the young age of most athletes, the use of CCT and nuclear cardiology techniques should be restricted to athletes with unclear stress echocardiography or CMR.

Cardiovascular magnetic resonance: Diagnostic utility and specific considerations in the pediatric population

Cardiovascular magnetic resonance is a non-invasive imaging modality which is emerging as important tool for the investigation and management of pediatric cardiovascular disease. In this review we describe the key technical and practical differences between scanning children and adults, and highlight some important considerations that must be taken into account for this patient population. Using case examples commonly seen in clinical practice, we discuss the important clinical applications of cardiovascular magnetic resonance, and briefly highlight key future developments in this field.

The Role of Cardiac MRI in the Diagnosis and Risk Stratification of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM), the most common genetic cardiomyopathy, is a disease characterised by substantial heterogeneity. Although the majority of patients with HCM remain asymptomatic with near-normal longevity, a small, but important, subset remain at risk for a wide range of clinical outcomes including sudden death. Cardiovascular magnetic resonance (CMR), with its high spatial resolution and tomographic imaging capability, has emerged as an imaging modality particularly well suited to characterise the phenotypic expression of HCM. CMR helps in the diagnosis of HCM by identifying areas of hypertrophy not well visualised by echocardiography, providing more accurate wall thickness measurements and differentiating HCM from other causes of left ventricular (LV) hypertrophy. CMR has led to the identification of novel subgroups of patients with HCM, including those with LV apical aneurysms (a subgroup at increased risk for ventricular arrhythmias and thromboembolic stroke), as well as abnormalities that contribute to LV outflow obstruction. Additionally, contrast-enhanced CMR with late-gadolinium enhancement (LGE) has recognised patients with extensive LGE (≥15 % LV myocardium) as individuals who may be at increased risk of sudden death, independent of other high-risk features, with implications on management strategies including consideration for primary prevention implantable cardioverter defibrillator therapy. These observations justify an expanded role of CMR in the routine clinical assessment of patients with HCM.

Prevalence and predictors of asymmetric hypertensive heart disease: insights from cardiac and aortic function with cardiovascular magnetic resonance

AIMS

We sought to determine the prevalence of asymmetric hypertensive heart disease (HHD) overlapping morphologically with hypertrophic cardiomyopathy (HCM) and to determine predictors of this pattern of hypertensive remodelling.

METHODS AND RESULTS

One hundred and fifty hypertensive patients underwent 1.5 T cardiovascular magnetic resonance imaging. Twenty-one patients were excluded due to concomitant cardiac pathology that may confound the hypertrophic response, e.g. myocardial infarction, moderate-severe valvular disease, or other cardiomyopathy. Asymmetric HHD was defined as a segmental wall thickness of ≥15 mm and >1.5-fold the opposing wall in ≥1 myocardial segments, measured from short-axis cine stack at end-diastole. Ambulatory blood pressure, myocardial replacement fibrosis, aortic distensibility and aortoseptal angle were investigated as predictors of asymmetric HHD by multivariate logistic regression. Out of 129 hypertensive subjects (age: 51 ± 15 years, 50% male, systolic blood pressure: 170 ± 30 mmHg, diastolic blood pressure: 97 ± 16 mmHg), asymmetric HHD occurred in 21%. Where present, maximal end-diastolic wall thickness (EDWT) was 17.8 ± 1.9 mm and located exclusively in the basal or mid septum. In asymmetric HHD, aortoseptal angle (114 ± 10° vs. 125 ± 9° vs. 123 ± 12°, P < 0.05, respectively) was significantly reduced compared to concentric left ventricular hypertrophy (LVH) and compared to no LVH, respectively. Aortic distensibility in asymmetric HHD (1.01 ± 0.60 vs. 1.83 ± 1.65 mm²/mmHg × 10³, P < 0.05, respectively) was significantly reduced compared to subjects with no LVH. Age (odds ratio [95th confidence interval]: 1.10 [1.02-1.18], P < 0.05) and indexed LV mass (1.09 [0.98-1.28], P < 0.0001) were significant, independent predictors of asymmetric HDD.

CONCLUSIONS

Asymmetric HHD morphologically overlapping with HCM, according to the current ESC guidelines, is common. Postulating a diagnosis of HCM on the basis of EDWT of ≥15 mm should be made with caution in the presence of arterial hypertension particular in male subjects with elevated LV mass.

Diagnostic accuracy of standard axial 64-slice chest CT compared to cardiac MRI for the detection of cardiomyopathies

OBJECTIVE

To assess the diagnostic accuracy of standard axial chest CT compared with cardiac MRI for cardiomyopathies.

METHODS

The standard axial 64-slice chest CTs of 49 patients with cardiomyopathies and 27 controls were blindly assessed for the presence of a cardiomyopathy by two independent readers. Qualitative and quantitative analysis included assessment of: (i) interatrial septal thickness, (ii) left atrial diameter, (iii) myocardial hypertrophy, thinning or fat, (iv) myocardial and papillary muscle calcification, (v) papillary muscle thickness, (vi) calcified coronary artery segments, (vii) left ventricular (LV) diameter, (viii) interventricular septal thickness and (ix) right ventricular diameters. Cardiac MRI was the gold standard.

RESULTS

There were 21 (42.9%) dilated, 16 (32.7%) hypertrophic, 8 (16.3%) ischaemic and 4 other (8.2%) (LV non-compaction × 2, amyloid, idiopathic restrictive) patients with cardiomyopathies. An LV diameter of 47 mm, interventricular septal thickness of 14 mm and coronary artery/papillary muscle calcification on axial chest CT best distinguished dilated, hypertrophic and ischaemic cardiomyopathies from controls, respectively; kappa = 0.45 (moderate interobserver agreement). The sensitivity (95% confidence interval), specificity, positive- and negative-predictive values (95% confidence interval) and diagnostic accuracy of chest CT in diagnosing cardiomyopathies were 68% (52-83), 100%, 100%, 66% (55-85) and 80%, respectively.

CONCLUSION

Cardiomyopathies may be detected on standard chest CT with good sensitivity and high specificity.

ADVANCES IN KNOWLEDGE

It is useful to assess for an underlying cardiomyopathy on standard chest CT, especially in a patient with unexplained dyspnoea.

Apical hypertrophic cardiomyopathy presenting as acute coronary syndrome

Apical hypertrophic cardiomyopathy is a rare variant of hypertrophic cardiomyopathy. It is characterized by a local hypertrophy of the apical segments and displays typical electrocardiographic and imaging patterns. The clinical manifestations are variable and range from an asymptomatic course to sudden cardiac death. The most frequent symptom is chest pain and thus apical hypertrophic cardiomyopathy can mimic the symptoms and repolarization disturbances indicative of acute coronary syndrome.

The role of imaging in the diagnosis and management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy, affecting approximately 1:500 people. As the yield of genetic testing is only about 35-60%, the diagnosis of HCM is still clinical and based on the demonstration of unexplained and usually asymmetric left ventricular (LV) hypertrophy by imaging modalities. In the past, echocardiography was the sole imaging modality used for the diagnosis and management of HCM. However, in recent years other imaging modalities such as cardiac magnetic resonance have played a major role in the diagnosis, management and risk stratification of HCM, particularly when the location of left ventricular hypertrophy is atypical (apex, lateral wall) and when the echocardiographic imaging is sub-optimal. However, the most unique contribution of cardiac magnetic resonance is the quantification of myocardial fibrosis. Exercise stress echocardiography is the preferred provocative test for the assessment of LV outflow tract obstruction, which is detected only on provocation in one-third of the patients.

Myocardial tissue characterization with magnetic resonance imaging

The availability of an accurate, noninvasive method using cardiac magnetic resonance imaging (MRI) to distinguish microscopic myocardial tissue changes at a macroscopic scale is well established. High-resolution in vivo monitoring of different pathologic tissue changes in the heart is a useful clinical tool for assessing the nature and extent of cardiac pathology. Cardiac MRI utilizes myocardial signal characteristics based on relaxation parameters such as T1, T2, and T2 star values. Identifying changes in relaxation time enables the detection of distinctive myocardial diseases such as cardiomyopathies and ischemic myocardial injury. The presented state-of-the-art review paper serves the purpose of introducing and summarizing MRI capability of tissue characterization in present clinical practice.

[Hypertrophic and restrictive cardiomyopathy. Differentiation by imaging]

The differentiation between hypertrophic and restrictive cardiomyopathies is often challenging in the routine clinical setting. Advances in the field of multimodal imaging have improved the diagnostics of these diseases and understanding of the underlying pathophysiology. Each imaging method, such as echocardiography, cardiac magnetic resonance imaging (CMR), cardiac computed tomography (CT) and coronary angiography including cardiac catheterization for pressure measurements, is of significant value in clinical diagnostics and also regarding therapeutic approaches and prognostic implications. This review gives an overview of developments of the past few years, describes recent insights and puts these findings into a scientific context. Particularly CMR has added valuable information to current knowledge by its unique potential of contrast-enhanced tissue characterization. Another promising CMR tool, parametric mapping has appeared on the horizon and may further deepen our understanding of cardiac pathophysiology as well as offer new therapeutic options to patients.

Diagnosis and management of hypertrophic cardiomyopathy

The clinical spectrum of hypertrophic cardiomyopathy (HCM) is complex and includes a variety of phenotypes, which leads to different types of manifestations. Although most of the patients are asymptomatic, a significant proportion of them will develop symptoms or risk of arrhythmias and sudden cardiac death (SCD). Therefore, the objectives of HCM diagnosis and management are to relieve the patients' symptoms (chest pain, heart failure, syncope, palpitations, etc.), prevent disease progression and major cardiovascular complications and SCD. The heterogeneity of HCM patterns, their symptoms and assessment is a challenge for the cardiologist.

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.

Role of multimodality cardiac imaging in the management of patients with hypertrophic cardiomyopathy: an expert consensus of the European Association of Cardiovascular Imaging Endorsed by the Saudi Heart Association

Taking into account the complexity and limitations of clinical assessment in hypertrophic cardiomyopathy (HCM), imaging techniques play an essential role in the evaluation of patients with this disease. Thus, in HCM patients, imaging provides solutions for most clinical needs, from diagnosis to prognosis and risk stratification, from anatomical and functional assessment to ischaemia detection, from metabolic evaluation to monitoring of treatment modalities, from staging and clinical profiles to follow-up, and from family screening and preclinical diagnosis to differential diagnosis. Accordingly, a multimodality imaging (MMI) approach (including echocardiography, cardiac magnetic resonance, cardiac computed tomography, and cardiac nuclear imaging) is encouraged in the assessment of these patients. The choice of which technique to use should be based on a broad perspective and expert knowledge of what each technique has to offer, including its specific advantages and disadvantages. Experts in different imaging techniques should collaborate and the different methods should be seen as complementary, not as competitors. Each test must be selected in an integrated and rational way in order to provide clear answers to specific clinical questions and problems, trying to avoid redundant and duplicated information, taking into account its availability, benefits, risks, and cost.

Diagnosis of apical hypertrophic cardiomyopathy: T-wave inversion and relative but not absolute apical left ventricular hypertrophy

BACKGROUND

Diagnosis of apical HCM utilizes conventional wall thickness criteria. The normal left ventricular wall thins towards the apex such that normal values are lower in the apical versus the basal segments. The impact of this on the diagnosis of apical hypertrophic cardiomyopathy has not been evaluated.

METHODS

We performed a retrospective review of 2662 consecutive CMR referrals, of which 75 patients were identified in whom there was abnormal T-wave inversion on ECG and a clinical suspicion of hypertrophic cardiomyopathy. These were retrospectively analyzed for imaging features consistent with cardiomyopathy, specifically: relative apical hypertrophy, left atrial dilatation, scar, apical cavity obliteration or apical aneurysm. For comparison, the same evaluation was performed in 60 healthy volunteers and 50 hypertensive patients.

RESULTS

Of the 75 patients, 48 met conventional HCM diagnostic criteria and went on to act as another comparator group. Twenty-seven did not meet criteria for HCM and of these 5 had no relative apical hypertrophy and were not analyzed further. The remaining 22 patients had relative apical thickening with an apical:basal wall thickness ratio >1 and a higher prevalence of features consistent with a cardiomyopathy than in the control groups with 54% having 2 or more of the 4 features. No individual in the healthy volunteer group had more than one feature and no hypertension patient had more than 2.

CONCLUSION

A cohort of individuals exist with T wave inversion, relative apical hypertrophy and additional imaging features of HCM suggesting an apical HCM phenotype not captured by existing diagnostic criteria.

The Role of Multimodality Cardiac Imaging for the Assessment of Sports Eligibility in Patients with Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) cannot be considered an innocent finding, but it is not necessarily a life-threatening condition. Athletes with BAV should undergo a thorough staging of the valve anatomy, taking into consideration hemodynamic factors, as well as aortic diameters and looking for other associated significant cardiovascular anomalies by use of a multimodality cardiac imaging approach. Furthermore an accurate follow-up is mandatory with serial cardiological controls in those allowed to continue sports.

Individualized cardiovascular risk assessment by cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) is gaining clinical importance in preventive medicine. Evidence on diagnostic accuracy and prognostic value, in addition to the development of faster imaging, increased availability of equipment and imaging expertise have led to a wide-spread use of CMR in a growing number of clinical indications. The first part of this review summarizes the role of CMR biomarkers for risk assessment focusing on the patients groups that benefit from the use of CMR. In the second part, the future directions for CMR are discussed and their role in prevention of cardiovascular disease.

2014 korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the korean society of cardiology and the korean society of radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

2014 Korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the Korean Society of Cardiology and the Korean Society of Radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

The role of magnetic resonance imaging in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inheritable cardiac disorder, with an estimated prevalence of 1:500 in the general population. Most cases of HCM are phenotypically expressed in adolescence or early adulthood but age-related penetrance with certain phenotypes is increasingly recognized. Clinical manifestations of HCM are usually the result of systolic and/or diastolic dysfunction, left ventricular outflow tract (LVOT) obstruction, arrhythmias and sudden cardiac death (SCD). In recent years magnetic resonance imaging (MRI) has become established as an important tool for the evaluation of suspected HCM as it can reliably establish the diagnosis, help distinguish HCM from other causes of left ventricular hypertrophy (LVH) and identify those patients at greatest risk of SCD. This article reviews the current status of MRI in the evaluation of the HCM patient including imaging protocols, disease characterization and the emerging role of MRI for risk stratification and proband screening.

A primer on the methods and applications for contrast echocardiography in clinical imaging

Contrast echocardiography is broadly described as a variety of techniques whereby the blood pool on cardiac ultrasound is enhanced with encapsulated gas-filled microbubbles or other acoustically active nano- or microparticles. The development of this technology has occurred primarily in response to the need improve current diagnostic applications of echocardiography such as the need to better define left ventricular cavity volumes, regional wall motion, or the presence or absence of masses and thrombi. A secondary reason for the development of contrast echocardiography has been to expand the capabilities of echocardiography. These new applications include myocardial perfusion imaging for detection of ischemia and viability, perfusion imaging of masses/tumors, and molecular imaging. The ability to fill all of these current and future clinical roles has been predicated on the ability to produce robust contrast signal which, in turn, has relied on technical innovation with regards to the microbubble contrast agents and the ultrasound imaging paradigms. In this review, we will discuss the basics of contrast echocardiography including the composition of microbubble contrast agents, the unique imaging methods used to optimize contrast signal-to-noise ratio, and the clinical applications of contrast echocardiography that have made a clinical impact.

Multimodality imaging in apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare morphologic variant of HCM in which the hypertrophy of myocardium is localized to the left ventricular apex. Symptoms of AHCM might vary from none to others mimic coronary artery disease including acute coronary syndrome, thus resulting in inappropriate hospitalization. Transthoracic echocardiography is the first-line imaging technique for the diagnosis of hypertrophic cardiomyopathies. However, when the hypertrophy of the myocardium is localized in the ventricular apex might results in missed diagnosis. Aim of this paper is to review the different imaging techniques used for the diagnosis of AHCM and their role in the detection and comprehension of this uncommon disease.

Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement

Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

Functional, morphological and electrocardiographical abnormalities in patients with apical hypertrophic cardiomyopathy and apical aneurysm: correlation with cardiac MR

Objective

The prognosis of apical hypertrophic cardiomyopathy (APH) has been benign, but apical myocardial injury has prognostic importance. We studied functional, morphological and electrocardiographical abnormalities in patients with APH and with apical aneurysm and sought to find parameters that relate to apical myocardial injury.

Methods

Study design: a multicentre trans-sectional study. Patients: 45 patients with APH and 5 with apical aneurysm diagnosed with transthoracic echocardiography (TTE) in the database of Hamamatsu Circulation Forum. Measure: the apical contraction with cine-cardiac MR (CMR), the myocardial fibrotic scar with late gadolinium enhancement (LGE)-CMR, and QRS fragmentation (fQRS) defined when two ECG-leads exhibited RSR’s patterns.

Results

Cine-CMR revealed 27 patients with normal, 12 with hypokinetic and 11 with dyskinetic apical contraction. TTE misdiagnosed 11 (48%) patients with hypokinetic and dyskinetic contraction as those with normal contraction. Apical LGE was apparent in 10 (83%) and 11 (100%) patients with hypokinetic and dyskinetic contraction, whereas only in 11 patients (41%) with normal contraction (p<0.01). Patients with dyskinetic apical contraction had the lowest left ventricular ejection fraction, the highest prevalence of ventricular tachycardia, and the smallest ST depression and depth of negative T waves. The presence of fQRS was associated with impaired apical contraction and apical LGE (OR=8.32 and 8.61, p<0.05).

Conclusions

CMR is superior to TTE for analysing abnormalities of the apex in patients with APH and with apical aneurysm. The presence of fQRS can be a promising parameter for the early detection of apical myocardial injury.

Significance of left ventricular apical-basal muscle bundle identified by cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

AIMS

Cardiovascular magnetic resonance (CMR) has improved diagnostic and management strategies in hypertrophic cardiomyopathy (HCM) by expanding our appreciation for the diverse phenotypic expression. We sought to characterize the prevalence and clinical significance of a recently identified accessory left ventricular (LV) muscle bundle extending from the apex to the basal septum or anterior wall (i.e. apical-basal).

METHODS AND RESULTS

CMR was performed in 230 genotyped HCM patients (48 ± 15 years, 69% male), 30 genotype-positive/phenotype-negative (G+/P-) family members (32 ± 15 years, 30% male), and 126 controls. Left ventricular apical-basal muscle bundle was identified in 145 of 230 (63%) HCM patients, 18 of 30 (60%) G+/P- family members, and 12 of 126 (10%) controls (G+/P- vs. controls; P < 0.01). In HCM patients, the prevalence of an apical-basal muscle bundle was similar among those with disease-causing sarcomere mutations compared with patients without mutation (64 vs. 62%; P = 0.88). The presence of an LV apical-basal muscle bundle was not associated with LV outflow tract obstruction (P = 0.61). In follow-up, 33 patients underwent surgical myectomy of whom 22 (67%) were identified to have an accessory LV apical-basal muscle bundle, which was resected in all patients.

CONCLUSION

Apical-basal muscle bundles are a unique myocardial structure commonly present in HCM patients as well as in G+/P- family members and may represent an additional morphologic marker for HCM diagnosis in genotype-positive status.

Percutaneous Septal Ablation in Hypertrophic Obstructive Cardiomyopathy: From Experiment to Standard of Care

Hypertrophic cardiomyopathy (HCM) is one of the more common hereditary cardiac conditions. According to presence or absence of outflow obstruction at rest or with provocation, a more common (about 60-70%) obstructive type of the disease (HOCM) has to be distinguished from the less common (30-40%) nonobstructive phenotype (HNCM). Symptoms include exercise limitation due to dyspnea, angina pectoris, palpitations, or dizziness; occasionally syncope or sudden cardiac death occurs. Correct diagnosis and risk stratification with respect to prophylactic ICD implantation are essential in HCM patient management. Drug therapy in symptomatic patients can be characterized as treatment of heart failure with preserved ejection fraction (HFpEF) in HNCM, while symptoms and the obstructive gradient in HOCM can be addressed with beta-blockers, disopyramide, or verapamil. After a short overview on etiology, natural history, and diagnostics in hypertrophic cardiomyopathy, this paper reviews the current treatment options for HOCM with a special focus on percutaneous septal ablation. Literature data and the own series of about 600 cases are discussed, suggesting a largely comparable outcome with respect to procedural mortality, clinical efficacy, and long-term outcome.

The relationship between electrocardiographic changes and CMR features in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy

To investigate the relationship between electrocardiographic (ECG) abnormalities and left ventricular (LV) segmental hypertrophy and myocardial fibrosis assessed by cardiovascular magnetic resonance (CMR) in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy (HCM). 118 asymptomatic or mildly symptomatic patients with HCM were examined with late gadolinium enhancement (LGE) CMR, 12-lead ECG, and echocardiography. The distribution and magnitude of LV segmental hypertrophy and LGE were assessed and analyzed in relation to ECG abnormalities. Abnormal electrocardiograms were found in 113 of 118 (95%) patients. Negative T waves were associated with greater apical septal thickness (P = 0.009) and an increased ratio of LV septum to free wall thickness (P = 0.01). Giant negative T waves (GNT) were found in 19 patients (16%), and were associated with apical HCM (P < 0.001), greater apical thickness (P = 0.004), and increased ratio of LV apical to basal wall thickness (P < 0.001). However, no significant association was demonstrated between GNT and apical LGE (P = 0.71). Abnormal Q waves were associated with greater basal anteroseptal thickness (P = 0.001), maximal basal thickness (P = 0.004), and more segments with extensive LGE (>75% wall thickness involved) (P = 0.001). LV hypertrophy was related to greater LV mass (P = 0.002) and LV end diastolic volume (P = 0.002). In addition, a modest but significant correlation was observed between maximum LV wall thickness and the Romhilt-Estes score (r = 0.41, P < 0.001). GNT were associated with apical HCM and an increased ratio of LV apical to basal wall thickness. Abnormal Q waves were related to basal anteroseptal hypertrophy and segmental extensive LGE.

Clinical significance of left ventricular apical aneurysms in hypertrophic cardiomyopathy patients: the role of diagnostic electrocardiography

OBJECTIVES

Some patients with hypertrophic cardiomyopathy (HCM) develop left ventricular apical aneurysm, leading to serious cardiovascular complications. The aims of this study were to identify the incidence and clinical course of HCM patients with apical aneurysms in Japan, and to evaluate the role of electrocardiography (ECG) as a screening test to detect apical aneurysms in HCM patients.

METHODS AND RESULTS

In a retrospective, single center analysis of a population of 247 HCM patients, 21 patients (8.5%) had left ventricular apical aneurysms. Their mean age was 60 ± 14 years (range: 23-77 years) at study entry. Over 4.7 ± 3.3 years of follow-up, 10 patients (47.6%) experienced an adverse clinical event (annual event rate: 10.1%/y), including five implantable cardioverter-defibrillator (ICD) implantations for ventricular tachycardia/ventricular fibrillation (VT/VF), an appropriate discharge of ICD for VT/VF, and four nonfatal thromboembolic strokes. Two patients developed systolic dysfunction (ejection fraction <50%). No sudden cardiac death or progressive heart failure was detected. Fourteen patients showed ST-segment elevation (≥ 1 mm) in V3 through V5 of ECG. In four patients, progression of the ST-segment elevation was recognized. When the ST-segment elevation was used to identify apical aneurysms in HCM patients, the sensitivity was 66.7%, and the specificity was 98.7%.

CONCLUSION

Apical aneurysms in HCM patients in Japan are not rare, and are associated with serious cardiovascular complications. The early diagnosis of apical aneurysms can be achieved by serial ECG.

ECG characteristics according to the presence of late gadolinium enhancement on cardiac MRI in hypertrophic cardiomyopathy

BACKGROUND

Late gadolinium enhancement (LGE) on cardiac MRI (CMR) has been described as an independent predictive factor of cardiovascular events among patients with hypertrophic cardiomyopathy (HCM). LGE and Q waves are considered as myocardial scar markers but their relation in the context of HCM is poorly established and has to be more supported. The objective of the study was to compare ECG findings in the presence or absence of LGE.

METHODS

42 patients with HCM confirmed by CMR were included in the study. ECG abnormalities including abnormal Q waves and five ECG scores of left ventricular hypertrophy were assessed and compared according to LGE presence and its extension. Some CMR features, such as septal to posterior wall thickness ratio, were also studied according to the presence of LGE and the presence of abnormal Q waves.

RESULTS

Abnormal Q waves were more prevalent in the LGE (+) group (60% vs 12%; p=0.002), but there was no correlation between location of Q waves on ECG and territory of LGE on CMR. Among patients with LGE, quantitative analysis of LGE was not different in the presence or absence of Q waves. In contrast to the LGE mass, septal to posterior wall thickness was higher in patients with abnormal Q waves (2.3±0.7 vs 1.6±0.5; p=0.012).

CONCLUSIONS

Although abnormal Q waves were more prevalent in the presence of LGE, no correlation was found with the LGE location and extent. These data suggest that abnormal electrical activation of the hypertrophied ventricular septum represented by a high septal to posterior wall thickness ratio seems to be an important mechanism of abnormal Q waves in HCM.

Systematic echocardiography is not efficacious when screening an ethnically diverse cohort of athletes in West Asia

BACKGROUND

The clinical and economic value of including systematic echocardiography (ECHO) alongside the 12-lead electrocardiograpm (ECG) when undertaking pre-participation screening in athletes has not been examined, yet several sporting organistations recommend its inclusion.

DESIGN

To examine the efficacy of systematic ECHO alongside the ECG, to identify sudden cardiac death (SCD) disease and to provide a cost-analysis of a government-funded pre-participation screening programme.

METHODS

A total 1628 athletes presented for cardiological consultation, ECG, and ECHO as standard, with further cardiac examinations performed if necessary to confirm or exclude pathology. The efficacy of systematic ECHO was compared to an ECG-led programme, with ECHO reserved as a follow-up examination.

RESULTS

To screen 1628 athletes with ECG and ECHO cost US$743,996. There were 54 24-h-blood pressure/ECG Holter recordings, 62 exercise tests, 25 CMRs, two electrophysiological studies, and two genetic tests, which cost US$67,734: total US$811,730. Eight athletes (0.5%) were identified with hypertrophic cardiomyopathy (HCM) and two (0.1%) with Wolff-Parkinson-White syndrome. The cost per identifed athlete was US$81,173. All 10 athletes presented an abnormal ECG. No athlete diagnosed with HCM was identified by ECHO in isolation. When adopting a ECG-led screening protocol, 15% of athletes required ECHO as a follow-up examination, resulting in a US$380,600 cost reduction (47% saving), with the cost per diagnosis reduced to US$43,113.

CONCLUSIONS

Athletes diagnosed with a disease associated with SCD were identified via an abnormal ECG and/or physical examination, personal symptoms, or family history. Screening athletes with systematic ECHO is not economically or clinically effective.

Advances of cardiovascular MRI in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic disease characterized by abnormal myocardial hypertrophy, which can lead to a wide clinical spectrum, including sudden cardiac death and heart failure. Cardiac MRI has a significant role in establishing the diagnosis of HCM. In the three principal management issues related to HCM; testing of family members of affected individuals; assessing the risk of sudden cardiac death from lethal ventricular arrhythmias; and selection of appropriate treatments for left ventricular outflow obstruction, cardiac MRI has established or emerging roles.