Myocardial Mechanics in Cardiomyopathies

Cardiomyopathies are a heterogeneous group of diseases that can be phenotypically recognized by specific patterns of ventricular morphology and function. The authors summarize recent clinical observations that mechanistically link the multidirectional components of left ventricular (LV) deformation with morphological phenotypes of cardiomyopathies for offering key insights into the transmural heterogeneity of myocardial function. Subendocardial dysfunction predominantly alters LV longitudinal shortening, lengthening and suction performance and contributes to the phenotypic patterns of heart failure (HF) with preserved ejection fraction (EF) seen with hypertrophic and restrictive patterns of cardiomyopathy. On the other hand, a more progressive transmural disease results in reduction of LV circumferential and twist mechanics leading to the phenotypic pattern of dilated cardiomyopathy and the clinical syndrome of HF with reduced (EF). A proper characterization of LV transmural mechanics, energetics, and space-time distributions of pressure and shear stress may allow recognition of early functional changes that can forecast progression or reversal of LV remodeling. Furthermore, the interactions between LV muscle and fluid mechanics hold the promise for offering newer mechanistic insights and tracking impact of novel therapies.     

Imaging methods in cardiomyopathies

The echocardiography, as a widely available and relatively inexpensive basic imaging method, fulfills an irreplaceable function of a screening method in cardiomyopathies. Among new imaging methods, three-dimensional (3D) echocardiography may prove useful, particularly in spongious and apical hypertrophic cardiomyopathies; speckletracking echocardiography in differentiation of athletic heart from hypertrophic cardiomyopathy, various types of restrictive cardiomyopathy (including the initial stages of cardiac amyloidosis) and distinguishing between stress and spongious cardiomyopathy. More detailed information may be provided by cardiac magnetic resonance imaging, especially in arrhythmogenic right ventricular cardiomyopathy and the prognostic assessment in all types of cardiomyopathies. A cardiac CT scan serves particularly for discrimination of ischemic heart disease and detection of various extracardiac structures. Nevertheless, an essential disadvantage of this method is the radiation exposure, preventing its use in long-term follow-up.     

Sudden cardiac death in nonischemic cardiomyopathy: Refining risk assessment

Sudden cardiac death (SCD) risk assessment among patients with nonischemic cardiomyopathy (NICM) has been has been less straightforward than for patients with ischemic cardiomyopathy. The common surrogate that has been associated with highest SCD risk for all cardiomyopathies, and which has been universally used to guide implantation of primary‐prevention implantable cardioverter‐defibrillators (ICDs), is left ventricular ejection fraction (LVEF) ≤35%. However, this practice has been called into question, especially in light of recent trials suggesting that ICD treatment may not be of additional survival benefit among those with NICM treated with optimal medical therapy. This Clinical Review attempts to offer refinements to the current practice of SCD risk assessment among patients with NICM, with specific focus on importance of NICM etiology and efforts to identify myocardial scarring and arrhythmogenic substrate, both of which may provide greater information about SCD risk than the LVEF alone. These concepts are illustrated further as they apply to hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and cardiac sarcoidosis, all of which are increasingly recognized NICM substrates associated with SCD and for which refinements for assessing risk are lacking in conventional guidelines.     

Tachycardia-Induced Cardiomyopathy Secondary to Right Ventricular Outflow Tract Ventricular Tachycardia: Improvement of Left Ventricular Systolic Function After Radiofrequency Catheter Ablation of the Arrhythmia

Cardiomyopathy Secondary to RVOT VT. Introduction : Several reports describe development of cardiomyopathics secondary to supraventricular tachycardia. Few reports have described cardiomyopathies secondary to ventricular tachycardia.
Methods and Results : We describe a patient who presented with dilated cardiomyopathy and repetitive nonsustained monomorphic ventricular tachycardia. Cardiac cathcterization showed hemodynamically insignificant coronary artery disease. Radiofrequency ablation of a right ventricular outflow tract ventricular tachycardia resulted in improvement of the left ventricular systolic function and resolution of heart failure symptoms.
Conclusions : This report suggests that right ventricular outflow tract ventricular tachycardia may cause reversible tachycardia-induced cardiomyopathy.     

Transient left ventricular ballooning syndrome

The transient left ventricular apical ballooning syndrome or takotsubo-like left ventricular dysfunction refers to the ventricular morphological features present in the heart of these patients. It resembles the Japanese Takotsubo, which means a “fishing pot for trapping octopuses”. This syndrome is characterized by transient left ventricular dysfunction, electrocardiographic changes and minimal release of myocardial enzymes that mimic acute anterior myocardial infarction, in patients without angiographic coronary artery disease.Several pathophysiological mechanisms have been proposed to explain it; however the precise aetiology remains unknown. This condition is transient and has a good prognosis, however Takotsubo cardiomyopathy as a new entity of acute heart failure, should be noted and thought of as a cause of sudden cardiac death. Its proper diagnosis and management greatly depends on our initial suspicion.     

Left ventricular solid body rotation in non‐compaction cardiomyopathy: A potential new objective and quantitative functional diagnostic criterion?

BACKGROUND: Left ventricular (LV) twist originates from the interaction between myocardial fibre helices that are formed during the formation of compact myocardium in the final stages of the development of myocardial architecture. Since non-compaction cardiomyopathy (NCCM) is probably caused by intrauterine arrest of this final stage, it may be anticipated that LV twist characteristics are altered in NCCM patients, beyond that seen in patients with impaired LV function and normal compaction. AIMS: The purpose of this study was to assess LV twist characteristics in NCCM patients compared to patients with non-ischaemic dilated cardiomyopathy (DCM) and normal subjects. METHODS AND RESULTS: The study population consisted of 10 patients with NCCM, 10 patients with DCM, and 10 healthy controls. LV twist was determined by speckle tracking echocardiography. In all controls and DCM patients, rotation was clockwise at the basal level and counterclockwise at the apical level. In contrast, in all NCCM patients the LV base and apex rotated in the same direction. CONCLUSIONS: These findings suggest that 'LV solid body rotation', with near absent LV twist, may be a new sensitive and specific, objective and quantitative, functional diagnostic criterion for NCCM.     

Systematic review of pregnancy in women with inherited cardiomyopathies

Pregnancy exposes women with inherited cardiomyopathies to increased risk for heart failure and arrhythmias. In this paper, we review the clinical course and management of pregnant women with the following inherited cardiomyopathies: hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction cardiomyopathy, and restrictive cardiomyopathy. We also discuss peripartum cardiomyopathy. Pregnancy is generally well tolerated in asymptomatic patients with inherited cardiomyopathies. However, worsening of the clinical condition can occur during pregnancy, despite intensive medical treatment. If prior cardiac events, poor functional class (New York Heart Association class III or IV), or advanced left ventricular systolic dysfunction are present, the risk of maternal cardiac complications during pregnancy are markedly increased. The postpartum condition is generally no worse than the antepartum condition, but no long-term follow-up studies have been reported. Preconception evaluation and counselling are important aspects of managing women with inherited cardiomyopathies. Genetic counselling and DNA testing should be offered to all women following the diagnosis of an inherited cardiomyopathy.     

2019 HRS expert consensus statement on evaluation,risk stratification,and management of arrhythmogenic cardiomyopathy: Executive summary

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.     

扩张性心肌病形成左心室血栓的相关因素分析

目的:通过超声心动图观察,探讨扩张性心肌病左心室血栓形成的相关因素。方法:根据超声心动图检查有、无左心室血栓,83例扩张性心肌病患者被分为A组(左室血栓组)和B组(左室无血栓组)。结果:左房内径、左室收缩期末内径、EF值、二尖瓣中等返流及主动脉瓣返流量在两组之间有显著差异(P<0.05~<0.01),而左室舒张末内径、室壁厚度及年龄、性别则无差异。结论:左室收缩功能的降低,左房内径的增大对左室血栓的形成有重要促进作用。而二尖瓣及主动脉瓣的中等量返流对左室血栓的形成有一定的对抗作用。     

Natural history and familial characteristics of isolated left ventricular non-compaction.

AIMS: Non-compaction of the left ventricle (LVNC) is a disorder of endomyocardial morphogenesis that results in multiple trabeculations in the left ventricular myocardium. The current literature suggests that LVNC in adults is rare and associated with a poor prognosis. Given that the disorder is present at birth and that several studies have reported asymptomatic familial disease in some patients, we hypothesized that there is a long pre-clinical phase of the disease. The aim of this study was to define the prognosis and familial incidence of LVNC. METHODS AND RESULTS: This study cohort comprised 45 patients (mean age at diagnosis 37 years) consecutively identified at a referral centre for cardiomyopathy over a 10-year period. Twenty-eight patients (62%) had dyspnoea at presentation; 41 (91%) an abnormal ECG; and 30 (66%) left ventricular dilatation and impaired systolic function. Nine patients (20%) had non-sustained ventricular tachycardia on 24 h Holter monitoring. Mean survival from death or transplantation was 97% at 46 months. There were three thromboembolic events in two patients (4%). On systematic family screening, 8 of 32 (25%) asymptomatic relatives had a range of echocardiographic abnormalities, including LVNC, LVNC with impaired systolic function, and left ventricular enlargement without LVNC. CONCLUSION: This study demonstrates that LVNC is associated with a better prognosis than previously reported. In patients with familial disease, relatives may have features consistent with dilated cardiomyopathy rather than LVNC.     

Left ventricular noncompaction associated with a pathogenic mutation in the MYH7 gene: Known mutation,different phenotype

Left ventricular noncompaction (LVNC) is a genetically heterogeneous cardiomyopathy, with familial and sporadic forms, but genetic testing only identifies a pathogenic mutation in a minority of cases. The main complications are heart failure, embolism and dysrhythmias. Herein we report a familial case of LVNC associated with a mutation in the MYH7 gene and review the literature regarding controversies in LVNC. A 50-year-old woman was referred to the cardiology clinic for palpitations. She underwent echocardiography and cardiac magnetic resonance imaging that revealed mild left ventricular systolic dysfunction and LVNC criteria. She had several episodes of non-sustained ventricular tachycardia and received an implantable cardioverter-defibrillator (ICD). Genetic testing revealed the c.1003G>C (p.Ala335Pro) mutation in the MYH7 gene. Familial screening showed clear genotype-phenotype cosegregation, which provided strong evidence for the pathogenic role of this mutation. To the best of our knowledge, this is the first report of LVNC associated with the p.Ala335Pro mutation in the MYH7 gene. This mutation has been described in hypertrophic cardiomyopathy, suggesting that the same pathogenic sarcomere mutation may be associated with different cardiomyopathies. This case also highlights the current difficulties regarding decisions on ICD implantation for primary prevention of sudden cardiac death in LVNC.     

Reduced and delayed untwisting of the left ventricle in patients with hypertension and left ventricular hypertrophy: a study using two-dimensional speckle tracking imaging.

AIMS: Newly developed two-dimensional ultrasound speckle tracking imaging allows measurements of left ventricular (LV) rotation and twist. Because LV untwisting predominantly occurs during the isovolumic relaxation period, its assessment reflects the process of LV relaxation. The aim of this study was to examine whether LV hypertrophy (LVH) adversely affects LV untwisting and abnormalities in LV untwisting could become a novel marker in assessing LV relaxation abnormalities. METHODS AND RESULTS: We acquired basal and apical LV short-axis images in 49 hypertensive patients. Using two-dimensional strain software, a time-domain speckle tracking was performed, and the mean value of LV rotation was obtained at each plane. LV twist was defined as apical rotation relative to the base. In order to adjust for inter-subject differences in heart rate, the time sequence was normalized to the percentage of systolic and diastolic duration. The degree of LV untwisting was calculated as the percentage of systolic twist : untwisting = (TwistES-Twistt/TwistES) x 100, where Twistt is twist at time t and TwistES is twist at end-systole. Although peak systolic twist was not different, early diastolic LV untwisting and untwisting rate during isovolumic relaxation period was significantly delayed and reduced in parallel to the severity of LVH, as assessed by LV mass index. CONCLUSION: The observed delayed and reduced diastolic untwisting during the isovolumic relaxation period noted in hypertensive patients with LVH may contribute towards the LV relaxation abnormality. Two-dimensional speckle tracking imaging is a novel tool which can be used for the non-invasive assessment of LV relaxation.     

Effect of nicorandil on left ventricular end-diastolic pressure during exercise in patients with hypertrophic cardiomyopathy.

AIMS: Impaired coronary microcirculation is thought to contribute to myocardial ischaemia, causing an abnormal increase in left ventricular end-diastolic pressure during exercise in individuals with hypertrophic cardiomyopathy. The effects of nicorandil on left ventricular end-diastolic pressure during exercise were examined in patients with this condition. METHODS AND RESULTS: Left ventricular pressures and dimensions were measured simultaneously during supine bicycle exercise in 23 patients with nonobstructive hypertrophic cardiomyopathy, before and after intravenous injection of either nicorandil (0.1 mg/kg) or propranolol (0.15 mg/kg). Exercise thallium-201 scintigraphy was also performed. Patients were grouped according to the changes in left ventricular end-diastolic pressure during exercise before treatment. Group I comprised 13 patients in whom left ventricular end-diastolic pressure increased progressively to abnormal values during exercise; group II comprised 10 patients in whom left ventricular end-diastolic pressure changed biphasically. The extents of both left ventricular hypertrophy and ischemic burden during exercise were greater in group I than in group II. Of the eight group I patients who received nicorandil, four individuals exhibited biphasic changes in left ventricular end-diastolic pressure during exercise after its administration whereas four subjects showed no such effect of the drug. Left ventricular end-diastolic pressure increased progressively during exercise after propranolol treatment in all 6 group II patients given this drug. CONCLUSION: Nicorandil has a salutary effect on the changes in left ventricular end-diastolic pressure during exercise in patients with hypertrophic cardiomyopathy.     

Effect of age and gender on left ventricular rotation and twist in a large group of normal adults — A multicenter study

Background

The newly developed 2-dimensional speckle tracking imaging (2D-STI) allows assessment of left ventricular (LV) rotation and twist. The aims of the present study are to establish normal values and to examine the effect of aging and gender on these parameters.

Methods

We studied 228 healthy subjects (109 males, mean age 44 ± 15 years, ranged 18–78 years). LV longitudinal and circumferential strain, rotation and twist were assessed by 2D-STI at basal, middle and apical levels of parasternal short-axis and apical 2-, 4- and 3-chamber views.

Results

The mean global LV longitudinal and circumferential strains were − 20.4 ± 3.4% and − 22.9 ± 3.1%, respectively. Of the 2,736 segments analyzed, 110 (8%) and 128 (9.4%) segments did not have optimal images for the assessment of basal and apical rotation. The basal rotation (− 9.6 ± 2.5°) was significantly lower than apical rotation (11.2 ± 4.3°, p < 0.0001) with a mean LV twist of 20.5 ± 4.5°. The longitudinal strain decreased with aging, which was accompanied by significant augmentations in circumferential strain, LV rotation and twist. There was no gender difference for rotational and twist measurements which had acceptable inter and intra-observer variabilities.

Conclusions

Evaluation of LV rotation and twist are feasible with 2D-STI. Older age rather than gender seems to augment global LV rotation and twist. This may be the compensatory mechanism as a result of aging-related decline in subendocardial function. These data can serve as the references for further evaluation of pathological myocardial motions in various cardiovascular diseases.     

起搏诱导性心肌病临床研究进展

起搏诱导性心肌病通常定义为长期右心室起搏出现左室射血分数的下降.然而最近的研究数据表明,仅依据左室射血分数下降来定义起搏诱导性心肌病可能低估了长期右心室起搏有害影响的发生率,当出现起搏诱导性心肌病时,主要的治疗方式为升级成心脏再同步化治疗,而最新的数据表明,传导系统起搏可能在预防和治疗起搏诱导性心肌病方面有一定优势.现...     

First evidence of premature ventricular complex-induced cardiomyopathy: a potentially reversible cause of heart failure

Tachycardia-induced cardiomyopathy is a well-recognized and reversible condition, but left ventricular dysfunction due to frequent isolated premature ventricular complexes (PVCs) has not been reported. We observed resolution of dilated cardiomyopathy in a patient after a focal source of PVCs was eliminated by radiofrequency ablation. In a subset of patients with heart failure, PVC-induced cardiomyopathy may be a potentially reversible cause of left ventricular dysfunction.     

A serious clinical course of a very elderly patient with takotsubo cardiomyopathy

An 86-year-old woman was admitted to our hospital because of vomiting and anorexia. Although serum cardiac markers, an electrocardiogram, and echocardiography suggested acute myocardial infarction, emergency cardiac catheterization revealed akinesis of the left ventricular apex without significant coronary artery stenosis. She was diagnosed as having takotsubo cardiomyopathy. The left ventricular dysfunction was considered transient and reversible but did not improve at all, contrary to our expectations. She died of worsening heart failure on day 14. We discuss this serious clinical course of a very elderly patient with takotsubo cardiomyopathy.     

经胸超声心动图评价高血压心脏病与左心室流出道梗阻的应用价值

目的:应用经胸超声心动图(transthoracic echocardiography,TTE),评价高血压心脏病与肥厚型心肌病(HCM)左心室流出道梗阻的二维及血流动力学特征,为临床鉴别诊断提供影像学依据。方法:左心室流出道梗阻患者31例,其中高血压性左心室流出道梗阻12例,肥厚型梗阻性心肌病19例,二维图像下测量两组患者的室间隔厚度及左心室后壁厚度,在静息状态和激发试验后测量两组患者的左心室流出道流速及最大压差,分别进行组间及组内比较。结果:室间隔厚度肥厚型心肌病组(19.6±1.8)mm明显高于高血压组(12.4±0.6)mm,差异有统计学意义(P<0.05)。左心室后壁厚度:肥厚型心肌病组(11.5±0.5)mm,高血压组(11.3±0.6)mm,两组间比较差异无统计学意义(P>0.05)。高血压组组内比较激发试验后左心室流出道流速(398.6±36.7)cm/s及压差[(68.4±12.9)mmHg,1 mmHg=0.133kPa],均高于静息状态下流速178.2±23.4)cm/s,压差(13.5±6.2)mmHg,差异有统计学意义(P<0.05)。结论:经胸超声心动图能准确评价左心室流出道梗阻的解剖结构与血流动力学特征,可准确鉴别梗阻类型及梗阻程度。     

Echocardiography for Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic cardiomyopathy. The prevalence of phenotypic expression, in the absence of another systemic or cardiac disease causing increased left ventricular (LV) wall thickness, is estimated to be 1:500. The frequency of clinical presentation is far less, highlighting the need for a non-invasive diagnostic imaging tool. Echocardiography is readily available and allows for structural characterization and hemodynamic assessment of the hypertrophic heart and to screen patients at-risk for HCM, such as first degree relatives of affected individuals, and differentiate HCM from the athletic heart. Echocardiography can also be used to assess for anatomic abnormalities of the mitral valve apparatus that may exacerbate LV outflow track obstruction and to further risk stratify patients during exercise. Finally, echocardiography plays an integral role in guiding alcohol septal ablation procedures.