Search

Aims  Many factors cause left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM). Previous studies reported that left ventricular basal muscle bundle (BMB) may be associated with LVOTO. We aimed to evaluate the role of BMB in LVOTO by echocardiography. Methods and results  Two hundred fifty-six patients diagnosed with HCM were recruited. The morphologic characteristics of left ventricular outflow tract (LVOT) were analysed. BMB was detected in 178 (69.5%) patients by echocardiography. Patients were separated by a resting or provocative LVOT gradient ≥30 mmHg or not. Compared to patients without LVOTO, patients with LVOTO had a significantly thicker basal septum, elongated anterior mitral leaflet (AML), shorter distance between the AML-free margin and the septum or BMB (M-sept/bundle), larger angle between the plane of the mitral valvular orifice and the ascending aorta (MV-AO angle), and higher prevalence of BMB (P < 0.05). According to multivariate analysis, the independent predictors of LVOTO were the presence of BMB, a large basal septum thickness, a short M-sept/bundle, a large MV-AO angle, and a large AML [odds ratio (95% confidence interval): 5.207 (1.381–19.633), 1.386(1.141–1.683), 0.615(0.499–0.756), 1.113(1.054–1.176), and 1.343(1.076–1.677), respectively, P < 0.05]. Of the 256 included patients, 139 underwent surgical myectomy. The transthoracic echocardiography, compared with surgical specimen, showed: sensitivity 98.3%, specificity 82.3%, positive predictive value 97.6%, negative predictive value 87.5%, and accuracy 96.4% to detect BMB. Conclusions BMB is common in HCM. BMB is a risk factor for LVOTO. [ABSTRACT FROM AUTHOR]

Background: Myocardial bridging (MB) is associated with various forms of arrhythmia. However, whether MB is a risk factor for atrial fibrillation (AF) in patients with hypertrophic obstructive cardiomyopathy (HOCM) remains unknown. This study aimed to identify the relationship between myocardial bridging of the left anterior descending coronary artery (MB-LAD) and AF in patients with HOCM.Methods: We reviewed the medical records of 1925 patients diagnosed with HOCM at Fuwai Hospital from January 2012 to March 2019. Patients with coronary artery disease, a history of heart surgery, and those who had not been subjected to angiography were excluded. Finally, 105 patients with AF were included in this study. The control group was matched in a ratio of 3:1 based on age and gender.Results: Forty-three patients were diagnosed with MB-LAD in this study. The presence of MB was significantly higher in patients with AF than in those without AF (19.0% vs. 7.3%; p = 0.001), although MB compression and MB length did not differ between the two groups. In conditional multivariate logistic analysis, MB (odds ratio [OR] 2.33; 95% confidence interval [CI] 1.08-5.01; p = 0.03), pulmonary arterial hypertension (OR 2.63; 95% CI 1.26-5.47; p = 0.01), hyperlipidemia (OR 1.83; 95% CI 1.12-3.00; p = 0.016), left atrial diameter (OR 1.09; 95% CI 1.05-1.13; p < 0.001), and interventricular septal thickness (OR 1.06; 95% CI 1.003-1.12; p = 0.037) were independent risk factors for AF in patients with HOCM.Conclusions: The presence of MB is an independent risk factor for AF in patients with HOCM. The potential mechanistic link between MB and the development of AF warrants further investigation. [ABSTRACT FROM AUTHOR]

Background and Aim: Recently alcohol septal ablation (ASA) has emerged as an alternative treatment for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) and a subgroup of HOCM patients with previous ASA may need myectomy. However, subsequent outcome and mechanism of residual obstruction has not been determined. This study aims to determine outcome after myectomy and mechanism of residual obstruction in HOCM patients with previous ASA.Methods: From February 2009 to June 2017, 38 HOCM patients with previous ASA underwent surgical septal myectomy at our institution. Seventy-six patients who underwent surgical septal myectomy initially were included as the comparison group through one-to-two propensity score matching method.Results: Fourteen available cardiac magnetic resonance images revealed inferior location and small area of infarcted myocardium induced by ASA in 12 patients and outside targeted location in two patients. During follow-up (median, 2.4; maximum, 7.8 years), event-free survival at 7 years was 83.2% in the previous ASA group and 94.6% in the comparison group, respectively (P = 0.0378). Multivariable analysis indicated previous ASA (hazard ratio, 4.28; 95% confidence intervals [CI], 1.20-15.26; P = 0.025) and postoperative left ventricular end-diastolic diameter (hazard ratio, 1.14; 95% CI, 1.05-1.23; P = 0.002) were independent predictors of adverse events.Conclusions: This study demonstrated that uncontrollable extent and location of infarcted myocardium induced by ASA may attribute to residual obstruction after previous ASA, and the long-term event-free survival after myectomy was inferior. It may provide special precaution to patient selection and the increased number of ASA practiced worldwide. [ABSTRACT FROM AUTHOR]

Background: The mid-term outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing coronary artery bypass graft (CABG) is unclear.Materials and Methods: We studied 44 patients with HOCM and coronary artery disease (CAD) who underwent septal myectomy and CABG) between 2011 and 2017. The control group was matched in a ratio of 4:1 based on age, sex, body mass index, hypertension, and chest pain.Results: Compared to patients without CAD, patients with CAD had a higher long-term cardiovascular mortality rate (0.6% vs 6.8%, P = 0.03; hazard ratio [HR] = 8.16, 95% confidence interval [CI]: 1.27-74.48, P = 0.03). In addition, 10 out of 176 (5.7%) patients without CAD and nine out of 44 (20.5%) patients with CAD achieved the secondary endpoints (progressive heart failure, unexplained syncope, stroke, atrial fibrillation, and myocardial infarction) (HR = 2.89, 95%CI: 1.03-8.12, P = 0.04). The 5-year survival rate and cardiovascular event-free survival rate were significantly higher in patients without CAD than in those with CAD (97.4% vs 93.9%, P = 0.03; 89.2% vs 80.1%; P = 0.04). In the multivariate analysis, presence of CAD, New York Heart Association class, and left atrial diameter were predictors of combined cardiovascular events when adjusted for age and male sex.Conclusions: The cardiovascular death and cardiovascular events are significantly increased in patients with HOCM and CAD who underwent CABG at the time of septal myectomy. [ABSTRACT FROM AUTHOR]

Background: Animal studies suggested that blocking the activation of the mammalian target of rapamycin (mTOR) pathway might be effective to treat cardiac hypertrophy in LEOPARD syndrome (LS) caused by PTPN11 mutations.Results: In the present study, mTOR pathway activity was examined in human myocardial samples from two patients with LS, four patients with hypertrophic cardiomyopathy (HCM), and four normal controls. The two patients with LS had p.Y279C and p.T468 M mutations of the PTPN11 gene, respectively. Although PTPN11 mutation showed initially positive regulation on phosphoinositide 3-kinase, overall the mTOR complex 1 pathway showed widely attenuated activity in LS. This included mildly hypophosphorylated mTOR and ribosomal protein S6 kinase and significantly hypophosphorylated Akt308 and ribosomal protein S6, which is similar to HCM. Akt473 is a basal molecule of the mTOR complex 2 pathway. Akt473 was less affected and showed hyperactivity in LS compared with HCM and normal controls. Additionally, MAPK/ERK kinase and ERK1/2 were significantly more phosphorylated in both HCM and LS than normal controls.Conclusions: In LS, the mTOR signaling pathway shows similar activity to HCM and is attenuated compared with normal controls. Thus, caution should be applied when using rapamycin to treat heart hypertrophy in LS. [ABSTRACT FROM AUTHOR]

Background: The prevalence of obstructive sleep apnoea (OSA) is high in patients with hypertrophic cardiomyopathy. The effect of septal myectomy on OSA is not clear. This study aimed to examine the association between hypertrophic obstructive cardiomyopathy and OSA before and after septal myectomy.Method: We included 85 consecutive patents with a confirmed diagnosis of hypertrophic obstructive cardiomyopathy who underwent septal myectomy. Polysomnography was performed in all patients before and 3 months after the surgery.Results: Of the 85 patients, 49 (58%) were diagnosed with OSA. Patients with OSA were significantly older than those without OSA. The incidence of atrial fibrillation significantly increased during the perioperative period in patients with OSA (p = 0.03). The severity of OSA significantly increased 3 months after surgery, as determined by the apnoea-hypopnoea index (AHI; p < 0.001), obstructive apnoea index (p = 0.024), and hypopnoea index (p = 0.003), whereas central apnoea index was decreased (p = 0.008). In the multivariate linear regression analysis, mean oxygen desaturation and time% with SpO2 <90% during sleep before surgery were significantly associated with increased AHI, independently of body mass index and sex (p = 0.026 and p = 0.007, respectively; adjusted R2 = 0.365).Conclusions: The severity of OSA significantly increased 3 months after septal myectomy as determined by AHI, obstructive apnoea index, and hypopnoea index. Mean oxygen saturation and time% with SpO2 <90% during sleep before surgery were independently associated with the increase of AHI. However, the specific mechanism of such deterioration of OSA after septal myectomy needs to be determined in detail. [ABSTRACT FROM AUTHOR]