The 50-year history, controversy, and clinical implications of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy: from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy

Dynamic obstruction in hypertrophic cardiomyopathy

PURPOSE OF REVIEW

The present article reviews the recent advances in the echocardiographic assessment of left ventricular outflow tract (LVOT) obstruction in hypertrophic cardiomyopathy (HCM). In particular, it highlights the role of novel imaging techniques in promoting our understanding of the pathophysiology of obstruction and discusses the prognostic value of information obtained from exercise echocardiography and the emerging role of image-guidance technologies for interventional relief of obstruction.

RECENT FINDINGS

The advent of novel echocardiography technologies, such as vector flow mapping, continues to expand our understanding of the exact mechanism of systolic anterior motion leading to dynamic LVOT obstruction by providing new insights into the interaction between pathologic mitral geometry and the left ventricular flow field. New studies provide evidence for the prognostic value of exercise echocardiography in the assessment of patients with HCM. Myocardial contrast perfusion imaging can delineate the anatomy of septal perforator arteries and identify the downstream septal perfusion bed, which is critical for safely guiding the procedure of alcohol septal ablation.

SUMMARY

Echocardiography represents a versatile, continuously evolving, and easily repeatable technique, allowing truly dynamic imaging studies, and is therefore most appropriate to evaluate a dynamic disease condition such as LVOT obstruction in HCM. It provides profound insights into the pathophysiology of LVOT obstruction, information on its clinical impact, and guidance for its relief by interventional strategies.

Radiofrequency septal reduction in symptomatic hypertrophic obstructive cardiomyopathy

BACKGROUND

Alcohol septal ablation remains the only approved nonsurgical therapeutic alternative for patients with drug-resistant hypertrophic obstructive cardiomyopathy (HOCM). Radiofrequency (RF) ablation offers another option for treating HOCM.

OBJECTIVE

The purpose of this study was to determine whether irrigated RF ablation can reduce symptomatic outflow tract obstruction in adults with HOCM.

METHODS

Patients with symptomatic HOCM and an outflow gradient of >50 mm Hg despite medication were offered RF ablation. In 11 patients, the hypertrophied interventricular septum was localized on a 3-dimensional mapping system and ablated via a transmitral or retrograde aortic approach.

RESULTS

Ten of 11(91%) patients had a significant and persistent reduction in resting and provocable left ventricular outflow tract gradients. Mean resting gradients at 12 months postprocedure were reduced by 85% (66.7 mm Hg at baseline to 10.0 mm Hg at 12 months); mean provocable gradients were reduced by 85% from baseline (136.2 mm Hg at baseline to 20.0 mm Hg at 12 months). Functional New York Heart Association heart classification improved from class 3.0 ± 0.0 in all patients to class mean of 1.8 ± 0.8.

CONCLUSION

RF septal ablation for the treatment of HOCM is a safe therapeutic option that allows for significant reduction in left ventricular outflow tract gradients, improvement in symptoms, and increase in efficacy rates comparable to reported rates for alcohol septal ablation.

Distinguishing ventricular septal bulge versus hypertrophic cardiomyopathy in the elderly

The burgeoning evidence of patients diagnosed with sigmoidal hypertrophic cardiomyopathy (HCM) later in life has revived the quest for distinctive features that may help discriminate it from more benign forms of isolated septal hypertrophy often labelled ventricular septal bulge (VSB). HCM is diagnosed less frequently than VSB at older ages, with a reversed female predominance. Most patients diagnosed with HCM at older ages suffer from hypertension, similar to those with VSB. A positive family history of HCM and/or sudden cardiac death and the presence of exertional symptoms usually support HCM, though they are less likely in older patients with HCM, and poorly investigated in individuals with VSB. A more severe hypertrophy and the presence of left ventricular outflow obstruction are considered diagnostic of HCM, though stress echocardiography has not been consistently used in VSB. Mitral annulus calcification is very prevalent in both conditions, whereas a restrictive filling pattern is found in a minority of older patients with HCM. Genetic testing has low applicability in this differential diagnosis at the current time, given that a causative mutation is found in less than 10% of elderly patients with suspected HCM. Emerging imaging modalities that allow non-invasive detection of myocardial fibrosis and disarray may help, but have not been fully investigated. Nonetheless, there remains a considerable morphological overlap between the two conditions. Comprehensive studies, particularly imaging based, are warranted to offer a more evidence-based approach to elderly patients with focal septal thickening.

Unique cause of right hemispheric syndrome: Embolism of myocardium after open septal myectomy

We present a novel case of acute ischemic stroke in the postoperative setting of open septal myectomy. A 24-year-old woman developed acute left hemiparesis and rightward eye deviation the morning after surgery. She underwent emergent endovascular stoke therapy by mechanical embolectomy with successful retrieval of a fragment of myocardium that was obstructing the right middle cerebral artery. To our knowledge there has been no previous case described of a myocardial fragment causing a proximal intracranial artery occlusion with resulting ischemia and infarction.

Usefulness of Von Willebrand Factor Activity Indexes to Predict Therapeutic Response in Hypertrophic Cardiomyopathy

Degraded by shear stress, loss of high-molecular-weight multimers of von Willebrand factor (VWF) correlates strongly with pressure gradient in aortic stenosis (AS) and obstructive hypertrophic cardiomyopathy (HC). We assessed VWF tests before and after interventions in HC and contrasted the severity of abnormalities in HC to patients with AS, mitral regurgitation, and left ventricular assist devices. Ninety patients with median (interquartile range) age 66 (53 to 72) years, 51% men, with HC had assessments of 3 VWF parameters and B-type natriuretic peptide before and after 26 discreet medical/pacing interventions, 22 alcohol septal ablations, and 28 ventricular septal myectomies. VWF multimers were abnormal in 87% of patients with obstructive HC versus 48% of patients with latent obstruction (p = 0.0001). VWF measurements correlated with peak instantaneous left ventricular outflow tract gradient, Spearman ρ 0.51 to 0.61, p <0.0001. For B-type natriuretic peptide, correlation with left ventricular outflow tract gradient was weaker, ρ = 0.37, p = 0.0005, but stronger with septal thickness or mitral E/e'. In pre-/post-medical treatment of HC, VWF multimers were abnormal in 73%/68% of patients, p = 0.74; pre-/post-septal ablation 74%/26%, p = 0.0035; and pre-/post-septal myectomy 75%/0%, p <0.0001. In obstructive HC, the degree VWF multimer loss was greater than in severe AS or severe mitral regurgitation and overlapped that seen in left ventricular assist devices. In conclusion, VWF activity indexes were predictably abnormal in patients with HC with resting obstruction to a degree where bleeding could be anticipated, accurately reflected gradient changes after intervention, and demonstrated complete normalization after septal myectomy.

ICD Therapy for Primary Prevention in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common and heterogeneous disorder that increases an individual's risk of sudden cardiac death (SCD). This review article discusses the relevant factors that are involved in the challenge of preventing SCD in patients with HCM. The epidemiology of SCD in patients is reviewed as well as the structural and genetic basis behind ventricular arrhythmias in HCM. The primary prevention of SCD with implantable cardioverter-defibrillator (ICD) therapy is the cornerstone of modern treatment for individuals at high risk of SCD. The focus here is on the current and emerging predictors of SCD as well as risk stratification recommendations from both North American and European guidelines. Issues related to ICD implantation, such as programming, complications and inappropriate therapies, are discussed. The emerging role of the fully subcutaneous ICD and the data regarding its implantation are reviewed.

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.

Minimally invasive septal myectomy for the treatment of hypertrophic obstructive cardiomyopathy and intrinsic mitral valve disease

OBJECTIVE

Transaortic left ventricular septal myectomy described by Morrow is a classical procedure for the treatment of systolic anterior motion of the mitral apparatus associated with hypertrophic obstructive cardiomyopathy (HOCM). We aimed to review our results of transmitral septal myectomy and mitral valve repair/replacement in patients with intrinsic mitral valve disease associated with HOCM, operated on through a minimally invasive approach.

METHODS

Between 2005 and 2014, 19 patients [7 men (37%); mean (SD) age, 69.4 (14.5) years] were treated with minimally invasive approach for degenerative mitral regurgitation and HOCM. Preoperative peak left ventricular outflow tract (LVOT) gradient was 66 (24) mm Hg. Severe mitral regurgitation was diagnosed in 16 cases (84%). New York Heart Association functional class III to IV heart failure was present in 13 patients (68%).

RESULTS

Fifteen patients (79%) underwent mitral valve replacement, and four patients (21%) underwent mitral valve repair. Left ventricular outflow tract obstruction was corrected directly in all patients via the mitral valve with septal myectomy/myotomy, avoiding aortotomy in majority of the patients. No significant prolongation of extracorporeal circulation/aortic cross-clamping times was observed (P = 0.41 and P = 0.67, respectively) when compared with a similar population without HOCM. No iatrogenic ventricular septal defect developed in treated patients. No hospital mortality occurred. Resting LVOT gradient reduced at discharge to 13 (22) mm Hg (P = 0.025).

CONCLUSIONS

Transmitral left ventricular septal myectomy in patients with degenerative mitral valve disease is quite a simple, feasible, and effective technique and does not require aortotomy in most cases. It can be performed with low early mortality and satisfactory resolution of LVOT obstruction in a minimally invasive setting.

Clinical benefits of a specialised clinic for hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac condition, with a range of investigation and management options available. Recent research has recommended management within multidisciplinary-dedicated HCM centres.

AIM

To assess the clinical impact of attendance at a specialised clinic on the management of HCM.

METHODS

A retrospective study of patients attending the HCM Clinic @ The Alfred during the first 2 years of operation was performed. Outcome measures comprised improvements in management of HCM as a result of attending the clinic including risk stratification and further investigations, medication changes, referral for implantable cardioverter-defibrillators (ICD) and septal reduction therapy, and screening of first-degree relatives (FDR).

RESULTS

Following specialised clinic attendance, there was an increase in patients investigated with 24-h Holter monitoring by 39%, stress echocardiography by 21% and cardiac magnetic resonance imaging by 70%. Medications were optimised in 47% of patients. Six per cent of patients underwent ICD implantation and 13% underwent septal myectomy. Seventy new FDR were screened identifying 10 new cases of HCM.

CONCLUSIONS

Attendance at our specialised HCM clinic leads to facilitation of cardiac investigations, optimisation of medical therapy, streamlining of referrals for ICD implantation and septal reduction therapy, and improved family screening. Referral to a specialised clinic offering comprehensive management should be considered for all patients with HCM.

Dynamic left ventricular outflow obstruction in situs inversus with levocardia

A 69-year-old man with situs inversus, levocardia and inverted great arteries developed severe dynamic left ventricular outflow tract (LVOT) obstruction with systolic anterior motion of the anterior mitral leaflet. There was no asymmetric septal hypertrophy. A possible mechanism of the LOVT obstruction in the present case may have been related to an abnormally long and bent outflow tract resulting from overriding of the right ventricle over the LVOT due to a congenital malposition of the heart. Mitral valve replacement with septal myectomy was performed in order to eliminate systolic anterior motion. The postoperative course has been excellent.

Morphological and Electrical Characteristics in Patient with Hypertrophic Cardiomyopathy: Quantitative Analysis of 864 Korean Cohort

PURPOSE

Although several studies have reported the morphological and electrical characteristics in patients with hypertrophic cardiomyopathy (HCM), comparison between asymmetric and apical HCM has not been investigated in a reasonably sized cohort.

MATERIALS AND METHODS

Echocardiography and electrocardiography were quantitatively analyzed in patients with HCM in a Korean tertiary referral center.

RESULTS

Of 864 patients (mean age 55.4±14.2 years, 68.9% men), 255 (29.5%) patients had apical HCM, 553 (64.0%) patients asymmetric HCM, and 56 (6.4%) patients mixed type HCM. In echocardiographic evaluations, about three quarters of patients (75.8%) had left atrial enlargement. Left ventricular (LV) dilatations and systolic dysfunction were observed in 6.1% and 2.4%, respectively. QRS widening, PR prolongation, and pathologic Q wave are frequent in patients with asymmetric HCM, while LV strain is frequent in patient with apical HCM. The prevalence of J-point elevations (9.4% in inferior, 2.2% in lateral leads) were substantially higher than that in general population. Giant negative T wave was observed in 15.0% of total patients (32.2% in apical, 6.2% in asymmetric, 25% in mixed type). There was no significant correlation between the thickness of the apical wall and the amplitude of T wave inversion (r=-0.005, p=0.71).

CONCLUSION

In a large cohort of HCM including apical type, repolarization abnormalities, including early repolarization and QT prolongation as well as LV strain, were significantly observed. T wave inversion was not appropriate for screening of HCM and not correlated with apical wall thickness.

Inherited cardiomyopathies--Novel therapies

Cardiomyopathies arising due to a single gene defect represent various pathways that evoke adverse remodeling and cardiac dysfunction. While the gene therapy approach is slowly evolving and has not yet reached clinical "prime time" and gene correction approaches are applicable at the bench but not at the bedside, major advances are being made with molecular and drug therapies. This review summarizes the contemporary drugs introduced or being tested to help manage these unique disorders bearing a major impact on the quality of life and survival of the affected individuals. The restoration of the RNA reading frame facilitates the expression of partly functional protein to salvage or alleviate the disease phenotype. Chaperones are used to prevent the degradation of abnormal but still functional proteins, while other molecules are given for pathogen silencing, to prevent aggregation or to enhance clearance of protein deposits. The absence of protein may be managed by viral gene delivery or protein therapy. Enzyme replacement therapy is already a clinical reality for a series of metabolic diseases. The progress in molecular biology, based on the knowledge of the gene defect, helps generate small molecules and pharmaceuticals targeting the key events occurring in the malfunctioning element of the sick organ. Cumulatively, these tools augment the existing armamentarium of phenotype oriented symptomatic and evidence-based therapies for patients with inherited cardiomyopathies.

Outcomes of acute myocardial infarction in patients with hypertrophic cardiomyopathy

BACKGROUND

Acute myocardial infarction is a recognized complication in patients with hypertrophic cardiomyopathy. However, limited data are available on outcomes of patients with hypertrophic cardiomyopathy and acute myocardial infarction.

METHODS

We analyzed the 2003-2011 Nationwide Inpatient Sample databases to identify all patients aged ≥18 years with a principal diagnosis of acute myocardial infarction. Patients with a concomitant diagnosis of hypertrophic cardiomyopathy were then identified and analyzed as a separate cohort. Multivariate logistic regression was used to compare outcomes in patients with acute myocardial infarction with and without hypertrophic cardiomyopathy.

RESULTS

Of 5,901,827 patients with acute myocardial infarction, 5688 (0.1%) had a diagnosis of hypertrophic cardiomyopathy. Patients with hypertrophic cardiomyopathy were older, more likely to be female, and less likely to have traditional cardiovascular risk factors. Compared with patients without hypertrophic cardiomyopathy, patients with hypertrophic cardiomyopathy were less likely to present with ST-elevation myocardial infarction and more likely to present with non-ST-elevation myocardial infarction. Patients with hypertrophic cardiomyopathy with ST-elevation myocardial infarction or non-ST-elevation myocardial infarction were less likely to receive revascularization. In the overall population with acute myocardial infarction, there was no difference in risk-adjusted in-hospital mortality between patients with and without hypertrophic cardiomyopathy (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.84-1.11; P = .59). In the population with ST-elevation myocardial infarction, patients with hypertrophic cardiomyopathy had lower risk-adjusted in-hospital mortality than those without hypertrophic cardiomyopathy (OR, 0.75; 95% CI, 0.63-0.91; P = .003), whereas in the population with non-ST-elevation myocardial infarction, there was no difference in risk-adjusted in-hospital mortality between patients with and without hypertrophic cardiomyopathy (OR, 0.97; 95% CI, 0.84-1.11; P = .63).

CONCLUSIONS

Patients with hypertrophic cardiomyopathy represent a small proportion of patients with acute myocardial infarction and are less likely to receive revascularization. Compared with patients without hypertrophic cardiomyopathy, patients with hypertrophic cardiomyopathy with ST-elevation myocardial infarction have lower risk-adjusted in-hospital mortality.

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.

Intervention in HCM: patient selection, procedural approach and emerging techniques in alcohol septal ablation

Hypertrophic cardiomyopathy (HCM) is a highly heterogeneous disease with varied patterns of hypertrophy. Basal septal hypertrophy and systolic anterior motion (SAM) of the mitral valve (MV) are the key pathophysiological components to left ventricular outflow tract (LVOT) obstruction in HCM. LVOT is associated with higher morbidity and mortality in patients with HCM. Percutaneous septal reduction therapy with alcohol septal ablation (ASA) can lead to a significant improvement in left ventricle haemodynamics, patient symptoms and perhaps prognosis. ASA delivers pure alcohol to an area of myocardium via septal coronary arteries; this creates damage to tissue akin to a myocardial infarction. The basal septal myocardium involved in SAM-septal contact is the target for this iatrogenic infarct. Appropriate patient selection and accurate delivery of alcohol are critical to safe and effective ASA. Securing the correct diagnosis and ensuring suitable cardiac anatomy are essential before considering ASA. Pre-procedural planning and intra-procedural imaging guidance are important to delivering precise damage to the desired area. The procedure is performed worldwide and is generally safe; the need for a pacemaker is the most prominent complication. It is successful in the majority of patients but room for improvement exists. New techniques have been proposed to perform percutaneous septal reduction. We present a review of the relevant pathophysiology, current methods and a summary of available evidence for ASA. We also provide a glimpse into emerging techniques to deliver percutaneous septal reduction therapy.

Three-dimensional haemodynamics in patients with obstructive and non-obstructive hypertrophic cardiomyopathy assessed by cardiac magnetic resonance

AIMS

The left ventricular outflow tract (LVOT) peak pressure gradient is an important haemodynamic descriptor in patients with hypertrophic cardiomyopathy (HCM); however, secondary alterations in aortic blood flow have not been well described in these patients. Aortic flow derangement is not easily assessed by traditional imaging methods, but may provide unique characterization of this disease. In this study, we demonstrated how four-dimensional (4D) flow MRI can assess LVOT peak pressure gradients in HCM patients and also evaluated the ascending aorta (AAo) haemodynamic derangement associated with HCM.

METHODS AND RESULTS

Obstructive (n = 12) and non-obstructive (n = 18) HCM patients were included in the study along with 10 normal volunteers. 4D flow MRI was used to visualize three-dimensional (3D) blood flow patterns within the LVOT and AAo, which were graded for the presence of helical flow as a marker of flow derangement (absent = 0, mild/moderate = 1, and severe = 2). MRI-estimated pressure gradient (ΔPMRI) was calculated from the peak systolic 3D blood velocity profile within the LVOT. There was higher grade helical flow in obstructive HCM patients compared with non-obstructive patients (P = 0.04) and volunteers (P < 0.001). Non-obstructive patients also had higher helix grade than volunteers (P = 0.002). There was a significant correlation between helical grade and increasing ΔPMRI (rS = 0.69, P < 0.001). Systolic anterior motion (SAM) of the mitral valve was associated with both increasing helix grade (P < 0.001) and ΔPMRI (P = 0.006).

CONCLUSIONS

Ascending aorta flow derangement occurs in both obstructive and non-obstructive HCM patients and can be identified using 4D flow MRI. The degree of flow derangement correlates with LVOT gradient, SAM, and outflow tract geometry.

Plasma cardiac troponin I concentration and cardiac death in cats with hypertrophic cardiomyopathy

BACKGROUND

The use of cardiac biomarkers to assist in the diagnosis of occult and symptomatic hypertrophic cardiomyopathy (HCM) in cats has been established. There is limited data describing their prognostic utility in cats with HCM.

HYPOTHESIS

Circulating concentrations of N-terminal B-type natriuretic peptide (NTproBNP) and cardiac troponin I (cTnI) predict cardiac death in cats with HCM.

ANIMALS

Forty-one cats diagnosed with HCM at a veterinary teaching hospital, between February 2010 and May 2011.

METHODS

Prospective investigational study. Plasma samples were collected from cats diagnosed with HCM and concentrations of NTproBNP and cTnI were analyzed at a commercial laboratory. Echocardiographic measurements from the day of blood sampling were recorded. Long-term outcome data were obtained. Associations with time to cardiac death were analyzed using Cox proportional hazards models.

RESULTS

When controlling for the presence/absence of heart failure and echocardiographic measures of left atrial size and function, cTnI > 0.7 ng/mL was independently associated with time to cardiac death. In univariable analysis, NTproBNP > 250 pmol/L was associated with cardiac death (P = .023), but this did not remain significant (P = .951) when controlling for the effect of clinical signs or left atrial size/function.

CONCLUSIONS AND CLINICAL IMPORTANCE

Plasma concentration of cTnI (cutoff >0.7 ng/mL) is a predictor of cardiac death in cats with HCM that is independent of the presence of heart failure or left atrial dilatation.

Hypertrophic cardiomyopathy: present and future, with translation into contemporary cardiovascular medicine

Hypertrophic cardiomyopathy (HCM) is a common inherited heart disease with diverse phenotypic and genetic expression, clinical presentation, and natural history. HCM has been recognized for 55 years, but recently substantial advances in diagnosis and treatment options have evolved, as well as increased recognition of the disease in clinical practice. Nevertheless, most genetically and clinically affected individuals probably remain undiagnosed, largely free from disease-related complications, although HCM may progress along 1 or more of its major disease pathways (i.e., arrhythmic sudden death risk; progressive heart failure [HF] due to dynamic left ventricular [LV] outflow obstruction or due to systolic dysfunction in the absence of obstruction; or atrial fibrillation with risk of stroke). Effective treatments are available for each adverse HCM complication, including implantable cardioverter-defibrillators (ICDs) for sudden death prevention, heart transplantation for end-stage failure, surgical myectomy (or selectively, alcohol septal ablation) to alleviate HF symptoms by abolishing outflow obstruction, and catheter-based procedures to control atrial fibrillation. These and other strategies have now resulted in a low disease-related mortality rate of <1%/year. Therefore, HCM has emerged from an era of misunderstanding, stigma, and pessimism, experiencing vast changes in its clinical profile, and acquiring an effective and diverse management armamentarium. These advances have changed its natural history, with prevention of sudden death and reversal of HF, thereby restoring quality of life with extended (if not normal) longevity for most patients, and transforming HCM into a contemporary treatable cardiovascular disease.

Morphologic features of the recipient heart in patients having cardiac transplantation and analysis of the congruence or incongruence between the clinical and morphologic diagnoses

Cardiac transplantation (CT) has been one of the great medical advances of the last nearly 50 years. We studied the explanted hearts of 314 patients having CT at Baylor University Medical Center Dallas from 1993 to 2012, and compared the morphologic diagnoses to the clinical diagnoses before CT. Among the 314 patients the morphologic and clinical diagnoses were congruent in 272 (87%) and incongruent in 42 (13%). Most of the incongruity occurred among the 166 patients with non-ischemic cardiomyopathy (non-IC) (36/166 [22%]), and of that group the major incongruity occurred among the patients with hypertrophic cardiomyopathy (7/17 [41%]), non-compaction left ventricular cardiomyopathy (NCLVC) (3/3 [100%]), mononuclear myocarditis (3/3 [100%]), arrhythmogenic right ventricular cardiomyopathy (ARVC) (4/4 [100%]), and cardiac sarcoidosis (8/8 [100%]). The phrase "non-IC" is a general term that includes several subsets of cardiac diseases and simply means "insignificant narrowing of 1 or more of the epicardial coronary arteries," but it does not specify the specific cause of the heart failure leading to CT. A number of cardiac illustrations are provided to demonstrate the morphologic variability occurring among the patients with IC and non-IC.

How does morphology impact on diastolic function in hypertrophic cardiomyopathy? A single centre experience

OBJECTIVES

It is unclear if morphology impacts on diastole in hypertrophic cardiomyopathy (HCM). We sought to determine the relationship between various parameters of diastolic function and morphology in a large HCM cohort.

SETTING

Tertiary referral centre from Stanford, California, USA.

PARTECIPANTS

383 patients with HCM and normal systolic function between 1999 and 2011. A group of 100 prospectively recruited age-matched and sex-matched healthy participants were used as controls.

PRIMARY AND SECONDARY OUTCOME MEASURES

Echocardiograms were assessed by two blinded board-certified cardiologists. HCM morphology was classified as described in the literature (reverse, sigmoid, symmetric, apical and undefined).

RESULTS

Reverse curvature morphology was most commonly observed (218 (57%). Lateral mitral annular E'<12 cm/s was present in 86% of reverse, 88% of sigmoid, 79% of symmetric, 86% of apical and 81% of undefined morphology, p=0.65. E/E' was similarly elevated (E/E': 12.3±7.9 in reverse curvature, 12.1±6.1 in sigmoid, 12.7±9.5 in symmetric, 9.4±4.0 in apical, 12.7±7.9 in undefined morphology, p=0.71) and indexed left atrial volume (LAVi)>40 mL/m(2) was present in 47% in reverse curvature, 33% in sigmoid, 32% in symmetric, 37% in apical and 32% in undefined, p=0.09. Each morphology showed altered parameters of diastolic function when compared with the control population. Left ventricular (LV) obstruction was independently associated with all three diastolic parameters considered, in particular with LAVi>40 mL/m(2) (OR 2.04 (95% CI 1.23 to 3.39), p=0.005), E/E'>15 (OR 4.66 (95% CI 2.51 to 8.64), p<0.001) and E'<8 (OR 2.55 (95% CI 1.42 to 4.53), p=0.001). Other correlates of diastolic dysfunction were age, LV wall thickness and moderate-to-severe mitral regurgitation.

CONCLUSIONS

In HCM, diastolic dysfunction is present to similar degrees independently from the morphological pattern. The main correlates of diastolic dysfunction are LV obstruction, age, degree of hypertrophy and degree of mitral regurgitation.

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.

Exercise, the athlete's heart, and sudden cardiac death

Physical activity is a potent therapy for both the prevention and treatment of cardiovascular disease. Exercise appears to most benefit people who are the least active. There is some evidence to suggest that a curvilinear relationship exists between exercise and survival, whereby beyond an optimal level of fitness, the principle of diminishing returns applies. Indeed, some go further in suggesting that there is evidence that extreme athletic training may be harmful in some individuals. The incidence of sudden cardiac death in athletes is greater than in matched, nonathletic counterparts, and this finding is driven by the provocation of an underlying cardiac abnormality by strenuous exertion. The task of detecting pathological myocardial substrate in athletes is made difficult by physiological adaptations to exercise that can mimic the appearance of cardiomyopathies and ion channelopathies in some individuals. This article details the clinical evaluation of the athlete with reference limits for cardiac physiological remodeling and discusses the diagnostic dilemmas that arise.

Evaluation of left ventricular myocardial perfusion and function using gated SPECT in patients with hypertrophic obstruction cardiomyopathy following percutaneous transluminal septal myocardial ablation

OBJECTIVE

This study was designed to evaluate the left ventricular myocardial perfusion and function in hypertrophic obstruction cardiomyopathy patients following percutaneous transluminal septal myocardial ablation (PTSMA) using rest single-photon emission computed tomography (SPECT) myocardial perfusion imaging.

PATIENTS AND METHODS

Thirty-five patients (24 men and 11 women, 48±11 years old) with hypertrophic obstruction cardiomyopathy underwent rest-gated Tc-MIBI SPECT imaging 4±10 days before (baseline) and 4.7±1.0 days (short-term) and 15.5±8.2 months (mid-term) after PTSMA. Semiquantitative and QGS quantitative evaluations of perfusion and function were carried out in 17 left ventricular segments.

RESULTS

Myocardial perfusion of the septum following PTSMA was significantly reduced compared with baseline in all patients (P<0.05), but the myocardial perfusion in the basal septum was significantly higher at mid-term compared with short-term following PTSMA (P<0.05). Left ventricular ejection fraction was significantly decreased following PTSMA (P<0.05). Regional wall motion assessed in the basal anterior, basal septum, and basal inferior areas following PTSMA was significantly reduced compared with baseline (P<0.05), and wall thickening of the interventricular septum was decreased following PTSMA (P<0.05).

CONCLUSION

Rest-gated SPECT imaging can be used to assess left ventricular myocardial perfusion and function and to investigate the efficacy of PTSMA during follow-up.

Hypertrophic cardiomyopathy in 2013: Current speculations and future perspectives

Hypertrophic cardiomyopathy (HCM), the most variable cardiac disease in terms of phenotypic presentation and clinical outcome, represents the most common inherited cardiomyopathic process with an autosomal dominant trait of inheritance. To date, more than 1400 mutations of myofilament proteins associated with the disease have been identified, most of them “private” ones. This striking allelic and locus heterogeneity of the disease certainly complicates the establishment of phenotype-genotype correlations. Additionally, topics pertaining to patients’ everyday lives, such as sudden cardiac death (SCD) risk stratification and prevention, along with disease prognosis, are grossly related to the genetic variation of HCM. This review incorporates contemporary research findings and addresses major aspects of HCM, including preclinical diagnosis, genetic analysis, left ventricular outflow tract obstruction and SCD. More specifically, the spectrum of genetic analysis, the selection of the best method for obstruction alleviation and the need for a unique and accurate factor for SCD risk stratification are only some of the controversial HCM issues discussed. Additionally, future perspectives concerning HCM and myocardial ischemia, as well as atrial fibrillation, are discussed. Rather than enumerating clinical studies and guidelines, challenging problems concerning the disease are critically appraised by this review, highlighting current speculations and recommending future directions.

Risk stratification in hypertrophic cardiomyopathy: time for renewal?

Systematic clinical assessment and careful monitoring of patients with hypertrophic cardiomyopathy (HCM) can be used to identify a cohort of patients that benefit from medical intervention and almost certainly improve long-term outcomes. One of the major limitations of the current approach is a lack of predictive power of individual risk factors, which means that many patients receive therapy. The aim of this review is to highlight other aspects of the disease, assessed using old and new medical technologies, that appear to provide new prognostic information. The hope for the future is that their incorporation in new risk algorithms will improve treatment for all HCM patients with the disease, irrespective of their vulnerability to adverse complications.

Management of hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is clinically defined as unexplained myocardial hypertrophy, and it is an autosomal dominant disease of the cardiac sarcomere. It is present in 1 in 500 in the general adult population, making it the most common genetic cardiovascular disease. The pathophysiology of HCM is complex, leading to significant variability in clinical presentation. This, combined with the lack of randomized trials, makes the management of these patients difficult.

FINDINGS

The majority of patients with HCM are asymptomatic without a substantial reduction in survival. However, a considerable portion of patients will experience significant symptoms and HCM-related death, and effective therapies are available for these patients. Patients may have symptoms of heart failure from outflow tract obstruction and/or restrictive physiology. Medical therapy targeted at the underlying pathophysiology should be used, and surgical myectomy or alcohol septal ablation is available for those with refractory symptoms. While the overall risk of sudden cardiac death (SCD) is low in HCM patients, some are at elevated risk for and experience SCD, a devastating outcome in young patients. Risk stratification for SCD and treatment with implantable cardioverter-defibrillators is paramount. Many HCM patients will also develop atrial fibrillation, and this is often poorly tolerated. A rhythm control strategy with antiarrhythmic drugs or catheter ablation is often necessary, and anticoagulation should be administered to reduce the risk of thromboembolism. Finally, family members of patients with HCM should be regularly screened with electrocardiography and echocardiography.

CONCLUSIONS

HCM is a complex disease with heterogeneous phenotypes and clinical manifestations. The management of HCM focuses on reducing symptoms of heart failure, preventing SCD, treating atrial fibrillation, and screening family members. Treatment should be tailored to the unique characteristics of each individual patient.

Comparison of long-term effect of dual-chamber pacing and alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

Introduction. Nonpharmacological treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM) comprises surgical myectomy (SME), alcohol septal ablation (ASA), and dual-chamber (DDD) pacing. The aim of the study was to compare the long-term effect of DDD pacing and ASA in symptomatic HOCM patients. Patients and Methods. We evaluated retrospective data from three cardiocenters; there were 24 patients treated with DDD pacing included and 52 treated with ASA followed for 101 ± 49 and 87 ± 23 months, respectively. Results. In the group treated with DDD pacing, the left ventricle outflow tract gradient (LVOTG) decreased from 82 ± 44 mmHg to 21 ± 21 mmHg, and NYHA class improved from 2.7 ± 0.5 to 2.1 ± 0.6 (both P < 0.001). In the ASA-treated group, a decline in LVOTG from 73 ± 38 mmHg to 24 ± 26 mmHg and reduction in NYHA class from 2.8 ± 0.5 to 1.7 ± 0.8 were observed (both P < 0.001). The LVOTG change was similar in both groups (P = 0.264), and symptoms were more affected by ASA (P = 0.001). Conclusion. ASA and DDD pacing were similarly effective in reducing LVOTG. The symptoms improvement was more expressed in patients treated with ASA.

Predictors of outcome after alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy. Special interest for the septal coronary anatomy

Background

Alcohol septal ablation (ASA) provides symptomatic relief in most but not all patients with hypertrophic obstructive cardiomyopathy (HOCM). Therefore we investigated predictors of outcome after ASA.

Methods

Clinical, echocardiographic, angiographic and procedural characteristics were analysed in 113 consecutive patients. Successful ASA was defined as NYHA ≤ 2 with improvement of at least 1 class combined with a resting gradient < 30 mmHg and provoked gradient < 50 mmHg at 4-month follow-up.

Results

In 37 patients ASA was not successful. In multivariate analysis, baseline gradient (OR 1.06 (1.01–1.11) per 5 mmHg, p = 0.024) and distance to the ablated septal branch (OR 1.09 (1.03–1.16) per mm, p = 0.004) were predictors of unsuccessful outcome. The combined presence of a non-ablated septal branch and a distance ≥ 19 mm to the ablated branch was a predictor of unsuccessful outcome (OR 5.88 (2.06–16.7), p < 0.001).

Conclusions

Baseline gradient and a greater distance from the origin of the left anterior descending artery to the ablated septal branch combined with a non-ablated proximal septal branch are associated with an unsuccessful outcome after ASA.

Enrichment analysis applied to disease prognosis

Enrichment analysis is well established in the field of transcriptomics, where it is used to identify relevant biological features that characterize a set of genes obtained in an experiment.

This article proposes the application of enrichment analysis as a first step in a disease prognosis methodology, in particular of diseases with a strong genetic component. With this analysis the objective is to identify clinical and biological features that characterize groups of patients with a common disease, and that can be used to distinguish between groups of patients associated with disease-related events. Data mining methodologies can then be used to exploit those features, and assist medical doctors in the evaluation of the patients in respect to their predisposition for a specific event.

In this work the disease hypertrophic cardiomyopathy (HCM) is used as a case-study, as a first test to assess the feasibility of the application of an enrichment analysis to disease prognosis. To perform this assessment, two groups of patients have been considered: patients that have suffered a sudden cardiac death episode and patients that have not.

The results presented were obtained with genetic data and the Gene Ontology, in two enrichment analyses: an enrichment profiling aiming at characterizing a group of patients (e.g. that suffered a disease-related event) based on their mutations; and a differential enrichment aiming at identifying differentiating features between a sub-group of patients and all the patients with the disease. These analyses correspond to an adaptation of the standard enrichment analysis, since multiple sets of genes are being considered, one for each patient.

The preliminary results are promising, as the sets of terms obtained reflect the current knowledge about the gene functions commonly altered in HCM patients, thus allowing their characterization. Nevertheless, some factors need to be taken into consideration before the full potential of the enrichment analysis in the prognosis methodology can be evaluated. One of such factors is the need to test the enrichment analysis with clinical data, in addition to genetic data, since both types of data are expected to be necessary for prognosis purposes.

[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.

A surgical experience of symptomatic sigmoid septum: drastic exacerbation of mitral regurgitation after sufficient ventricular septal myectomy

A 74-year-old woman presented with progressive dyspnea on exertion. Transthoracic echocardiography (TTE) demonstrated significant left ventricular outflow tract (LVOT) obstruction with a pressure gradient of 100 mmHg caused by a sigmoid septum (SS). Mitral regurgitation (MR) of a mild to moderate degree occurred due to systolic anterior motion (SAM) of the anterior mitral leaflet (AML), with no intrinsic mitral valve (MV) abnormality. Myectomy of the hypertrophied septal bulge ameliorated the pressure gradient to 8 mmHg with similar MR. However, just before the sternal closure, hemodynamic status deteriorated drastically to ventricular fibrillation. MR exacerbated to a severe degree with an uncertain etiology; thus, a mechanical prosthetic valve was implanted. The postoperative course was complicated by prolonged mechanical ventilation due to massive pulmonary edema and complete atrioventricular block (CAVB) requiring permanent pacemaker implantation. One year postoperatively, the patient is asymptomatic and TTE revealed no residual pressure gradient with an iatrogenic ventricular septal defect (VSD). This case, the first published surgical experience of SS, may indicate that secondary MR, which is usually relieved by sufficient myectomy in hypertrophic cardiomyopathy (HCM), can exacerbate markedly, and that myectomy might not be advisable in SS. The therapeutic strategy must be considered carefully before embarking on surgical intervention.

Dramatically different phenotypic expressions of hypertrophic cardiomyopathy in male cousins undergoing cardiac transplantation with identical disease-causing gene mutation

Described herein are certain findings in 2 male cousins who underwent cardiac transplantation for severe heart failure (HF), one of the diastolic type (ejection fraction ≈65%), and one of the systolic type (ejection fraction ≈20%), both the consequence of hypertrophic cardiomyopathy (HC), and each had identical disease-causing gene mutations. The implanted heart in one had normal-sized ventricular cavities and no grossly visible ventricular wall lesions (except in one papillary muscle) and the other patient had severely dilated ventricular cavities and multiple extensive ventricular wall scars. The heart mass and the age of onset of symptoms was similar in each patient. A number of other family members had evidence of HC.