超声心动图在肥厚型心肌病诊断中的应用价值

目的:分析超声心动图在肥厚型心肌病诊断中的应用效果及临床价值。方法:将某院2014年1月~2019年5月收治的200例肥厚型心肌病患者作为研究组,150例健康体检者作为常规组,对比两组的监测后的结果。结果:经分析,研究组的舒张末期直径、射血分数与常规组相比,无差异(P>0.05);研究组的心尖厚度较常规组厚(P<0.05);研究组的心肌重量较常规组重(P<0.05);研究组的左房径长于常规组(P<0.05)。结论:在肥厚型心肌病患者中超声心动图的应用具有较高的诊断价值,可以为临床治疗该疾病提供有效的依据。     

Sleep Disordered Breathing and Mortality in Patients With Hypertrophic Obstructive Cardiomyopathy Undergoing Septal Myectomy

ObjectiveTo determine the impact of sleep-disordered breathing (SDB) on survival in patients with hypertrophic cardiomyopathy (HCM) following septal myectomy.Patients and MethodsPatients with obstructive HCM undergoing septal myectomy from 2007 to 2016 were reviewed. Those who had an overnight oximetry test within 6 months before myectomy were included in analysis. Oxygen desaturation index was examined continuously and also categorically (SDB [>5/h] and severe SDB [>15/h]).ResultsA total of 619 of 1500 patients undergoing septal myectomy had overnight oximetry tests. Sleep-disordered breathing (oxygen desaturation index >5/h) was identified in 338 (54.6%) patients, and among those patients, 117 (18.9%) were classified as severe. Patients with SDB were older, had greater body mass index and body surface area, were more likely to have arterial hypertension and atrial fibrillation, and had an increased E/e’ ratio on Doppler echocardiography. Notably, there was no difference in preoperative resting left ventricular outflow tract pressure gradient between patients with SDB and those with normal overnight oximetry (55 (interquartile range: 25 to 86) mm Hg versus 52 (interquartile range: 21 to 85) mm Hg; P=.29). There was no difference in age-adjusted survival among patients with normal oximetry compared with those with mild SDB (hazard ratio: 0.98; 95% CI: 0.45 to 2.17), and severe SDB (hazard ratio: 1.06, 95% CI 0.42 - 2.71).ConclusionSleep-disordered breathing is present in more than half of patients with obstructive HCM in whom septal myectomy is indicated, and is mainly associated with aging, overweight, and male sex. However, SDB does not alter survival following septal myectomy.     

Association of HLA class II DRB1, DPA1 and DPB1 polymorphism with genetic susceptibility to idiopathic dilated cardiomyopathy in Chinese Han nationality

Although the aetiology of idiopathic dilated cardiomyopathy (IDC) remains unclear, many immunological abnormalities involving changes in cell-mediated and humoral immunity may be associated with cardiac impairment in IDC. Autoimmune mechanisms are likely to participate in the pathogenesis of at least a subgroup of IDC and components of the major histocompatibility complex may serve as markers for the propensity to develop immune-mediated myocardial damage. Human leukocyte antigen (HLA) class II genes, which are highly polymorphic, play an important role in the activating of immune responses and thus control the predisposition for or protection from IDC. This study explores the possible contribution of HLA-DRB and DP polymorphisms to IDC susceptibility. DNA genotyping for HLA-DRB1, DPA1 and DPB1 was performed using polymerase chain reaction-sequencing based typing (PCR-SBT) method in 198 IDC patients and 136 random selected healthy Han ethnic individuals living in Northern China. IDC patients were, sub-grouped into asymptomatics (subgroup A), with arrhythmia (subgroup B) and with overt congestive heart failure (subgroup C) according to the clinical manifestations and electrocardiogram or echocardiographic characteristics. ADP/ATP autoantibody was detected in IDC group by immunoblot analysis. The results revealed that HLA-DR15, -DPB*0601 frequencies were significantly elevated in IDC group compared with normal control. The DPB1*0601 allele in homozygous form or in combination with allele DPB1*2301 or *3901, was found present more often in IDC patients. The predominance of HLA-DR4 allele was observed in subgroup B after stratification. However, the frequency of DPB1*0101 allele increased in the control than in the IDC group. The frequency of HLA-DPB1*0601 allele was significantly higher in IDC patients with positive autoantibody against ADP/ATP carrier of myocardial mitochondria in contrast to those with negative autoantibody. We conclude that HLA-DR4, -DR15, -DPB1*0601 alleles confers susceptibility to, while DPB1*0101 allele confers protection from IDC among individuals of northern Chinese Han nationality. The glutamate at position 69 in the second exon of DPB1*0601, as a key residue for special conformation of HLA-DP, may confer predisposition to IDC. HLA-DR and -DP alleles polymorphisms may serve as genetic markers for IDC and be involved in the regulation of the immune specific response to auto or exterior anti-myocardium antibodies.     

Cardiac myosin binding protein-C restricts intrafilament torsional dynamics of actin in a phosphorylation-dependent manner

We have determined the effects of myosin binding protein-C (MyBP-C) and its domains on the microsecond rotational dynamics of actin, detected by time-resolved phosphorescence anisotropy (TPA). MyBP-C is a multidomain modulator of striated muscle contraction, interacting with myosin, titin, and possibly actin. Cardiac and slow skeletal MyBP-C are known substrates for protein kinase-A (PKA), and phosphorylation of the cardiac isoform alters contractile properties and myofilament structure. To determine the effects of MyBP-C on actin structural dynamics, we labeled actin at C374 with a phosphorescent dye and performed TPA experiments. The interaction of all three MyBP-C isoforms with actin increased the final anisotropy of the TPA decay, indicating restriction of the amplitude of actin torsional flexibility by 15–20° at saturation of the TPA effect. PKA phosphorylation of slow skeletal and cardiac MyBP-C relieved the restriction of torsional amplitude but also decreased the rate of torsional motion. In the case of fast skeletal MyBP-C, its effect on actin dynamics was unchanged by phosphorylation. The isolated C-terminal half of cardiac MyBP-C (C5–C10) had effects similar to those of the full-length protein, and it bound actin more tightly than the N-terminal half (C0–C4), which had smaller effects on actin dynamics that were independent of PKA phosphorylation. We propose that these MyBP-C-induced changes in actin dynamics play a role in the functional effects of MyBP-C on the actin–myosin interaction.     

Could the unfortunate outcome of pediatric acute myocarditis be predicted? Factors contributing to a poor outcome in myocarditis

ObjectiveMyocarditis has spontaneous resolution in 50% of patients. Our study aimed to define risk factors for developing dilated cardiomyopathy (DCM) and death in pediatric patients with acute myocarditis (AM).MethodsThe retrospective cohort study included all patients with treated AM. The Mother and Child Health Institute from January 2011 to March 2019.ResultsIn the study, 62 patients were included, 40 boys and 22 girls (11.15±5.86 years) with AM. Twelve out of sixty-two children had acute fulminant myocarditis. Four patients died in the acute phase of AM, and 11 developed DCM. Follow up was 27.14±36.52 months. Patients with poor outcome (DCM development) were under the age of seven (odds ratio [OR] 10.1; p=0.003), more likely to be girls (OR 4.6; p=0.03), and had fulminant myocarditis (OR 27.0; <0.001). An ejection fraction (EF) <55% and fractional shortening (FS) <30% increased risk of DCM 13- and 5-fold, respectively, but patients with EF between 40 and 55% remain at highest risk of developing DCM. There was a 12-fold increased risk for DCM in patients with left ventricular end-diastolic diameter Z score >2+. The receiver operator curve showed that the lactate dehydrogenase (LDH) cut-off value for developing DCM was 1780 mmol/l (sensitivity 80%, specificity 100%).ConclusionAcute fulminant myocarditis was an independent risk factor for DCM. Children with EF between 40 and 50% at admission were at highest risk of developing DCM. Lactate dehydrogenase value could be a significant prognostic value for the outcome of pediatric myocarditis.     

Clinical outcomes of catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy: Insights from the Johns Hopkins ARVC Program

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