Mid-term outcomes of biventricular obstruction and left ventricular outflow tract obstruction after surgery correction in child and adolescent patients with hypertrophic cardiomyopathy.
ABSTRACT: Data on the outcomes of hypertrophic cardiomyopathy (HCM) with biventricular obstruction are limited.Our aim is to compare mid-term outcomes of biventricular outflow tract obstruction (BVOTO) HCM, left ventricular outflow tract obstruction (LVOTO) HCM and nonobstructive hypertrophic cardiomyopathy (NO-HCM) in children and adolescents who were treated with standard medication or surgical resection.This retrospective study identified 21 BVOTO patients and recruited 27 LVOTO and 24 NO-HCM patients younger than 18 years presenting at our institution. The primary endpoint was all-cause death, and secondary endpoints were cardiovascular events.More BVOTO patients (61.9%) than LVOTO (19.2%) and NO-HCM patients (25%) exhibited New York Heart Association (NYHA) III/IV status (p < 0.01). Fourteen BVOTO and 16 LVOTO patients obtained a significant reduction of outflow tract pressure gradients after surgery (vs. preoperative baseline, p < 0.001). One of the 14 BVOTO patients died, whereas no deaths occurred among LVOTO patients. Three of 14 BVOTO surgery patients had complete heart block (CHB) and 4 had new right bundle branch block (RBBB), while no CHB or RBBB occurred in the LVOTO surgery patients. The BVOTO patients had a longer duration of aortic cross-clamping and postoperative hospital days than the LVOTO patients (p < 0.05). During a median 42-month follow-up, no deaths occurred among the remaining patients. The primary and secondary endpoint-free survival rates of the BVOTO group were comparable to those of the LVOTO and NO-HCM groups.In children and adolescents, BVOTO patients were associated with more severe symptoms than LVOTO and NO-HCM patients; however, good mid-term outcomes similar to those of the LVOTO and NO-HCM groups can be achieved with the application of contemporary cardiovascular treatment strategies. Notably, BVOTO surgery was associated with an increased risk of CHB and RBBB compared to LVOTO surgery.
Project description:Left ventricular outflow tract obstruction (LVOTO) has been reported with bio-prosthetic and mechanical mitral valves (MV), though it is more common with the former. The obstruction can be dynamic or fixed. We hereby report a case of fixed LVOTO following bio-prosthetic MV replacement (MVR).
Project description:To assess the global and regional right ventricular (RV) deformation in hypertrophic cardiomyopathy (HCM) patients with preserved right ventricular ejection fraction (RVEF) using 3.0-T cardiovascular magnetic resonance tissue tracking (CMR-TT). Eighty-two HCM patients and 32 age- and sex-matched healthy controls were enrolled. HCM patients were divided into groups depending on the presence or absence of right ventricular hypertrophy (RVH), RV late gadolinium enhancement (RV-LGE), and left ventricular outflow tract obstruction (LVOTO), respectively. The RV global and apical longitudinal peak strain (LPS) in HCM patients with RVH were significantly lower than that in HCM patients without RVH and controls (P?<?0.05). The global, apical and mid-ventricular LPS in HCM patients with RV-LGE were significantly lower than that in HCM patients without RV-LGE and controls (P?<?0.05). Lower LPS was demonstrated in HCM patients without RV-LGE compared with controls in apical and mid-ventricular levels (P?<?0.05). No significant difference was found regarding global and regional LPS in HCM patients with LVOTO compared without LVOTO (all P?>?0.05). CMR-TT was able to detect subclinical RV myocardial deformation prior to RVEF impairment, which was more severe in the presence of RVH and RV-LGE.
Project description:Highlights•Echocardiography is used to diagnose hypertrophic obstructive cardiomyopathy (HOCM) and Takotsubo cardiomyopathy (TCM).•Hypotension in a patient with TCM should be evaluated for left ventricular outflow tract obstruction (LVOTO).•Management of TCM is challenging in patients with HOCM with severe LVOTO.•Hypotension in LVOTO may paradoxically worsen with standard intravenous inotropes.•Fluid resuscitation, beta-blockers, alpha agonists, and intra-aortic balloon pump are the treatment options in LVOTO.
Project description:In 30-40% of hypertrophic cardiomyopathy (HCM) patients, symptomatic left ventricular (LV) outflow gradients develop only during exercise due to catecholamine-induced LV hypercontractility (inducible obstruction). Negative inotropic pharmacological options are limited to ?-blockers or disopyramide, with low efficacy and tolerability. We assessed the potential of late sodium current (INaL )-inhibitors to treat inducible obstruction in HCM.The electrophysiological and mechanical responses to ?-adrenoceptor stimulation were studied in human myocardium from HCM and control patients. Effects of INaL -inhibitors (ranolazine and GS-967) in HCM samples were investigated under conditions simulating rest and exercise.In cardiomyocytes and trabeculae from 18 surgical septal samples of patients with obstruction, the selective INaL -inhibitor GS-967 (0.5 ?M) hastened twitch kinetics, decreased diastolic [Ca2+ ] and shortened action potentials, matching the effects of ranolazine (10?M). Mechanical responses to isoprenaline (inotropic and lusitropic) were comparable in HCM and control myocardium. However, isoprenaline prolonged action potentials in HCM myocardium, while it shortened them in controls. Unlike disopyramide, neither GS-967 nor ranolazine reduced force at rest. However, in the presence of isoprenaline, they reduced Ca2+ -transient amplitude and twitch tension, while the acceleration of relaxation was maintained. INaL -inhibitors were more effective than disopyramide in reducing contractility during exercise. Finally, INaL -inhibitors abolished arrhythmias induced by isoprenaline.Ranolazine and GS-967 reduced septal myocardium tension during simulated exercise in vitro and therefore have the potential to ameliorate symptoms caused by inducible obstruction in HCM patients, with some advantages over disopyramide and ?-blockers.
Project description:Hypertrophic cardiomyopathy (HCM) is an inherited disease of the heart muscle characterized by otherwise unexplained thickening of the left ventricle. Left ventricular outflow tract (LVOT) obstruction is present in approximately two-thirds of patients and substantially increases the risk of disease complications. Invasive treatment with septal myectomy or alcohol septal ablation can improve symptoms and functional status, but currently available drugs for reducing obstruction have pleiotropic effects and variable therapeutic responses. New medical treatments with more targeted pharmacology are needed, but the lack of preclinical animal models for HCM with LVOT obstruction has limited their development. HCM is a common cause of heart failure in cats, and a subset exhibit systolic anterior motion of the mitral valve leading to LVOT obstruction. MYK-461 is a recently-described, mechanistically novel small molecule that acts at the sarcomere to specifically inhibit contractility that has been proposed as a treatment for HCM. Here, we use MYK-461 to test whether direct reduction in contractility is sufficient to relieve LVOT obstruction in feline HCM. We evaluated mixed-breed cats in a research colony derived from a Maine Coon/mixed-breed founder with naturally-occurring HCM. By echocardiography, we identified five cats that developed systolic anterior motion of the mitral valve and LVOT obstruction both at rest and under anesthesia when provoked with an adrenergic agonist. An IV MYK-461 infusion and echocardiography protocol was developed to serially assess contractility and LVOT gradient at multiple MYK-461 concentrations. Treatment with MYK-461 reduced contractility, eliminated systolic anterior motion of the mitral valve and relieved LVOT pressure gradients in an exposure-dependent manner. Our findings provide proof of principle that acute reduction in contractility with MYK-461 is sufficient to relieve LVOT obstruction. Further, these studies suggest that feline HCM will be a valuable translational model for the study of disease pathology, particularly LVOT obstruction.
Project description:Cardiovascular magnetic resonance (CMR) imaging in patients with hypertrophic cardiomyopathy (HCM) enables the assessment of not only left ventricular (LV) hypertrophy and scarring but also the severity of mitral regurgitation. CMR assessment of mitral regurgitation is primarily based on the difference between LV stroke volume (LVSV) and aortic forward flow (Ao) measured using the phase-contrast (PC) technique. However, LV outflow tract (LVOT) obstruction causing turbulent, non-laminar flow in the ascending aorta may impact the accuracy of aortic flow quantification, leading to false conclusions regarding mitral regurgitation severity. Thus, we decided to quantify mitral regurgitation in patients with HCM using Ao or, alternatively, main pulmonary artery forward flow (MPA) for mitral regurgitation volume (MRvol) calculations.The analysis included 143 prospectively recruited subjects with HCM and 15 controls. MRvol was calculated as the difference between LVSV computed with either the inclusion (LVSVincl) or exclusion (LVSVexcl) of papillary muscles and trabeculations from the blood pool and either Ao (MRvolAoi or MRvolAoe) or MPA (MRvolMPAi or MRvolMPAe). The presence or absence of LVOT obstruction was determined based on Doppler echocardiography findings.MRvolAoi was higher than MRvolMPAi in HCM patients with LVOT obstruction [47.0 ml, interquartile range (IQR)?=?31.5-60.0 vs. 35.5 ml, IQR?=?26.0-51.0; p <?0.0001] but not in non-obstructive HCM patients (23.0 ml, IQR?=?16.0-32.0 vs. 24.0 ml, IQR?=?15.3-32.0; p?=?0.26) or controls (18.0 ml, IQR?=?14.3-21.8 vs. 20.0 ml, IQR?=?14.3-22.0; p?=?0.89). In contrast to controls and HCM patients without LVOT obstruction, in HCM patients with LVOT obstruction, aortic flow-based MRvol (MRvolAoi) was higher than pulmonary-based findings (MRvolMPAi) (bias?=?9.5 ml; limits of agreement: -11.7-30.7 with a difference of 47 ml in the extreme case). The differences between aortic-based and pulmonary-based MRvol values calculated using LVSVexcl mirrored those derived using LVSVincl. However, MRvol values calculated using LVSVexcl were lower in all the groups analyzed (HCM with LVOT obstruction, HCM without LVOT obstruction, and controls) and with all methods of MRvol quantification used (p???0.0001 for all comparisons).In HCM patients, LVOT obstruction significantly affects the estimation of aortic flow, leading to its underestimation and, consequently, to higher MRvol values than those obtained with MPA-based MRvol calculations.
Project description:Background:Ebstein's anomaly (EA) is mainly thought of as a right heart condition, however, congenital left-sided lesions can co-exist. Therefore, it is paramount to include the left side of the heart as part of a routine investigation in these patients. We present a 57-year-old symptomatic patient with EA and progressive tricuspid regurgitation (TR) associated with acquired left ventricular outflow obstruction (LVOTO). Case summary:A 57-year-old women, known to have severe EA presented with shortness of breath and chest pain on exertion secondary to progression of the tricuspid valve regurgitation and right ventricle dilatation leading to a dynamic compression of the left outflow tract requiring surgical intervention. Discussion:Left ventricular obstruction secondary to severe TR and dilation of the right ventricle can present and remain silent at rest but becoming significant on exertion. Therefore, we recommend that all patients with EA and significant TR undergo exercise echocardiography at regular intervals to specifically look for acquired dynamic LVOTO.
Project description:Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric left ventricular (LV) hypertrophy and diastolic dysfunction, which leads to LV outflow tract obstruction (LVOTO) in the majority of cases. Mutations in genes encoding sarcomeric proteins cause HCM and are identified in more than half of the patients (sarcomere-mutation positive, SMP). Currently, more than 1500 HCM-causing mutations are known. Approximately 80% of mutations are located in the MYH7 and MYBPC3 genes, encoding for the thick filament proteins β-myosin heavy chain (β-MHC) and cardiac myosin-binding protein C (cMyBP-C), respectively. Less frequent are mutations in the TNNT2 and TNNI3 genes, encoding for the thin filament proteins cardiac troponin T (cTnT) and I (cTnI). Here, we applied an unbiased proteomics approach in a large number of myectomy samples from a clinically well-characterized HCM patient group to define HCM-specific derailments as well as genotype-specific changes at protein level. Our study shows that the downregulation of metabolic pathways and the upregulation of extracellular matrix proteins are the most prominent HCM-specific disease characteristics that are present in all samples independent of their genotype.
Project description:This case report concerns an 81-year-old woman with previously well-controlled hypertrophic obstructive cardiomyopathy (HOCM). She was referred to our hospital because of the acute onset of takotsubo syndrome. Echocardiography revealed basal hyperkinesis due to takotsubo syndrome superimposed on septal hypertrophy, which resulted in the reappearance of prominent left ventricular outflow tract obstruction (LVOTO). Although she developed cardiogenic shock triggered by atrial fibrillation, LVOTO was successfully mitigated by aggressive fluid resuscitation, rhythm control, and the administration of ?-blocker. We herein report a rare case with catastrophic hemodynamics due to the incidental combination of HOCM and takotsubo syndrome.
Project description:BACKGROUND:Brain microstructural maturation progresses rapidly in the third trimester of gestation and first weeks of life, but typical microstructural development may be influenced by the presence of critical congenital heart disease (CHD). OBJECTIVE:The aim of this study was to investigate the pattern of white matter (WM) microstructural development in neonates with different types of critical CHD. The secondary aim was to examine whether there is an association between WM microstructural maturity and neonatal ischemic brain injury. METHODS:For this prospective, longitudinal cohort study, 74 term born neonates underwent diffusion tensor imaging (DTI) before (N = 56) and after (N = 71) cardiac surgery performed <30 days of life for transposition of the great arteries (TGA), single ventricle physiology with aortic arch obstruction (SVP-AO), left- (LVOTO) or right ventricle outflow tract obstruction (RVOTO). Microstructural integrity was investigated by fractional anisotropy (FA) and by mean diffusivity (MD) in 16 white matter (WM) structures in three WM regions with correction for postmenstrual age. Ischemic brain injury was defined as moderate-severe white matter injury or stroke. RESULTS:Before cardiac surgery, the posterior parts of the corona radiata and internal capsule showed significantly higher FA and lower MD compared to the anterior parts. Centrally-located WM structures demonstrated higher FA compared to peripherally-located structures. Neonates with TGA had higher FA in projection-, association- and commissural WM before surgery, when compared to other CHD groups. Neonates with LVOTO showed lower preoperative MD in these regions, and neonates with SVP-AO higher MD. Differences in FA/MD between CHD groups were most clear in centrally located WM structures. Between CHD groups, no differences in postoperative FA/MD or in change from pre- to postoperative FA/MD were seen. Neonatal ischemic brain injury was not associated with pre- or postoperative FA/MD. CONCLUSIONS:Collectively, these findings revealed brain microstructural WM development to follow the same organized pattern in critical CHD as reported in healthy and preterm neonates, from posterior-to-anterior and central-to-peripheral. Neonates with TGA and LVOTO showed the most mature WM microstructure before surgery and SVP-AO the least mature. Degree of WM microstructural immaturity was not associated with ischemic brain injury.