Myocardial bridging in obstructive hypertrophic cardiomyopathy: a risk factor for myocardial fibrosis.

BACKGROUND: Myocardial bridging (MB) is common in patients with hypertrophic cardiomyopathy (HCM). There are sparse data on the impact of MB on myocardial fibrosis in HCM. This study was designed to evaluate the relationship between MB and myocardial fibrosis in patients with obstructive HCM. METHODS: In this cohort study, retrospective data were collected from a high-volume HCM center. Patients with obstructive HCM who underwent septal myectomy and preoperative cardiac magnetic resonance (CMR) were screened from 2011 to 2018. RESULTS: Finally, 492 patients were included in this study, with an average age of 45.7 years. Of these patients, 76 patients had MB. MB occurred mostly in the left anterior descending artery (73/76). The global extent of late gadolinium enhancement (LGE) was correlated with the degree of systolic compression (r = 0.33, p = 0.003). Multivariable linear regression analysis revealed that the degree of systolic compression was an independent risk factor for LGE (ß = 0.292, p = 0.007). The LGE fraction of basal and mid anteroseptal segments in patients with severe MB (compression ratio ≥ 80%) was significantly greater than that in patients with mild to moderate MB (compression ratio < 80%). During a median follow-up of 28 (IQR: 15-52) months, 15 patients died. Kaplan-Meier analysis did not identify differences in all-cause death (log-rank p = 0.63) or cardiovascular death (log-rank p = 0.72) between patients undergoing MB-related surgery and those without MB. CONCLUSIONS: MB with severe systolic compression was significantly associated with a high extent of fibrosis in patients with obstructive HCM. Concomitant myotomy or coronary artery bypass grafting might provide excellent survival similar to that of patients without MB. Identification of patients with severe MB and providing comprehensive management might help improve the prognosis of patients with HCM.

Systemic inflammation is associated with myocardial fibrosis in patients with obstructive hypertrophic cardiomyopathy.

AIMS: Chronic low-grade inflammation, often observed in hypertrophic cardiomyopathy (HCM), promotes adverse ventricular remodelling. This study aimed to investigate the relationship between inflammatory markers and myocardial fibrosis (MF) in patients with HCM. METHODS AND RESULTS: This study included 102 patients with complete baseline data who underwent septal myectomy. Myocardial samples were stained with Masson's trichrome and analysed to determine myocardial collagen content and MF levels. Plasma levels of inflammatory markers were measured using standard laboratory procedures. Univariate and multivariate logistic regression analyses were performed to explore the relationship between the inflammatory markers and MF. Among the 102 participants included in the analysis, the mean age was 48.9 years, with 69 [67.6%] being men. The overall MF ranged from 2.5% to 40.7% (mean = 15.2 ± 8.1%, median = 13.0%, IQR = 9.9%-18.4%). Participants were divided into two groups based on a median MF of 13%. The high MF group had a larger left atrial diameter and left ventricular ejection fraction. Levels of interleukin (IL)-2, tumour necrosis factor (TNF)-α and interferon (IFN)-α were significantly higher in patients with high MF compared to those with low MF (2.3 vs. 4.0 pg/mL, 3.1 vs. 3.9 pg/mL, 4.2 vs.4.7 pg/mL, respectively; all P < 0.05). In multivariate models adjusted for age, sex and other clinical features, IL-2, IL-5 and TNF-α, were correlated with increased interstitial MF [odds ratio (OR): 1.54, 95% confidence interval (CI): 1.10-2.14; OR: 1.42, 95% CI: 1.02-1.98; OR: 1.33, 95% CI: 1.04-1.70]. After additional adjustment for imaging indicators, IL-2 and TNF-α remained significant (OR: 1.49, 95% CI: 1.06-2.09, P = 0.021; OR:1.35, 95% CI: 1.01-1.80, P = 0.044). The correlation analysis between inflammation and replacement fibrosis assessed by CMR in 97 patients revealed that 72 (74.2%) showed late gadolinium enhancement (LGE). No significant correlation was found between inflammatory markers and the presence or extent of LGE. CONCLUSIONS: Higher levels of IL-2 and TNF-α were associated with increased histopathological interstitial MF in patients with HCM. Given the gradual progression of MF in HCM, initiating anti-inflammatory treatment in the early stages may delay its progression.

MYH7 mutation is associated with mitral valve leaflet elongation in patients with obstructive hypertrophic cardiomyopathy.

Mitral valve (MV) leaflet elongation is recognized as a primary phenotypic expression of hypertrophic cardiomyopathy (HCM) that contributes to obstruction. This study investigates the correlation between MV length and genotype mutations in the two predominant genes, myosin-binding protein C (MYBPC3), and the ß-myosin heavy chain (MYH7) in patients with obstructive HCM (OHCM). Among the 402 OHCM patients, there were likely pathogenic or pathogenic variations in MYH7 (n = 94) and MYBPC3 (n = 76), along with a mutation-negative group (n = 212). Compared to genotype-negative patients, genotype-positive individuals exhibited elongated MV length, thicker interventricular septum, and increased instances of late gadolinium enhancement. Notably, MYH7 mutations were associated with a more severe disease trajectory than MYBPC3 mutations. After adjusting for potential confounders, multivariate linear regression analysis revealed that MYH7 gene mutations and left ventricular volume were independently associated with MV leaflet elongation. The study indicates that mutations in MYH7 and hemodynamics factors are significant risk factors for elongated MV leaflet. Consequently, regular assessment of MV length, especially in patients with MYH7 mutation and enlarged LV volume, is crucial for timely preoperative strategic planning and improved prognosis.

SARC Gene Mutation Is Associated With Myocardial Fibrosis Measured by Histopathology and Cardiac Magnetic Resonance in Patients With Hypertrophic Cardiomyopathy.

Background Sarcomere gene mutation and myocardial fibrosis are both associated with poorer clinical outcomes in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to determine the relationship between sarcomere gene mutation and myocardial fibrosis measured by both histopathology and cardiac magnetic resonance (CMR). Methods and Results Two hundred twenty-seven patients with HCM who underwent surgical treatment, genetic testing, and CMR were enrolled. We retrospectively analyzed basic characteristics, sarcomere gene mutation, and myocardial fibrosis measured by CMR and histopathology. In our study, the mean age was 43 years, and 152 patients (67.0%) were men. A total of 107 patients (47.1%) carried a positive sarcomere gene mutation. The myocardial fibrosis ratio was significantly higher in the late gadolinium enhancement (LGE)+ group (LGE+ 14.3±7.5% versus LGE- 9.0±4.3%; P=0.001). Patients with HCM with SARC+ showed a high probability of fibrosis both in histopathology (myocardial fibrosis ratio 15.3±8.0% versus 12.4±6.5%; P=0.003) and CMR examination (LGE+ 98.1% versus 84.2%; P<0.001; LGE quantification 8.3% versus 5.8%; P<0.001). Linear regression analysis showed that sarcomere gene mutation (B=2.661; P=0.005) and left atrial diameter (B=0.240; P=0.001) were related factors for histopathological myocardial fibrosis. Also, the myocardial fibrosis ratio was significantly higher in the MYH7 (myosin heavy chain) group (MYH7 18.1±9.6% versus MYBPC3 [myosin binding protein C] 13.1±5.2%; P=0.019). Conclusions Patients with HCM with positive sarcomere gene mutation had a higher myocardial fibrosis extent than patients without mutation, and a significant difference in myocardial fibrosis was also observed between the MYBPC3 and MYH7 groups. In addition, a high consistency was found between CMR-LGE and histopathological myocardial fibrosis in patients with HCM.

Impact of Body Mass Index on Postoperative Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy Undergoing Septal Myectomy.

Background Obesity is an established cardiovascular risk factor in patients with hypertrophic cardiomyopathy. Postoperative atrial fibrillation (POAF) is one of the most common complications after surgery in patients with obstructive hypertrophic cardiomyopathy (OHCM). We aimed to determine the impact of body mass index (BMI) on the occurrence of POAF in patients with OHCM who underwent septal myectomy. Methods and Results In all, 712 OHCM patients without previous atrial fibrillation who underwent septal myectomy were identified. Patients were stratified into 3 groups based on BMI. Of these, 224 (31.5%) had normal weight (BMI<24 kg/m2), 339 (47.6%) were overweight (BMI, 24 to <28 kg/m2), and 149 (20.9%) were obese (BMI≥28 kg/m2). Overweight and obese patients had increased levels of left atrial diameter (P<0.001) and left ventricular end-diastolic diameter (P<0.001), compared with patients with normal weight. Among 184 patients (25.8%) developing POAF, 32 cases (14.3%) occurred in the normal weight group, 100 cases (29.5%) occurred in the overweight group, and 52 cases (34.9%) occurred in the obese group (P<0.001). Logistic regression analysis indicated that overweight (odds ratio [OR]: 2.161, 95% CI, 1.333-3.503; P=0.002) or obesity (OR, 2.803; 95% CI, 1.589-4.944; P<0.001), age (OR, 1.037; 95% CI, 1.018-1.057; P<0.001), and left atrial diameter (OR, 1.060; 95% CI, 1.027-1.095; P<0.001) were independently associated with the occurrence of POAF in patients with OHCM. Conclusions Overweight and obesity are strong predictors of POAF in patients with OHCM. Strategies aimed at lowering BMI may be a potential way to prevent POAF.

Radiofrequency and cryoballoon ablation improve cognitive function in patients with atrial fibrillation.

ABSTRACT: Atrial fibrillation is considered to be the most common arrhythmia in the clinic, and it gradually increases with age. In recent years, there has been increasing evidence that atrial fibrillation may exacerbate the progression of cognitive dysfunction. The current guidelines recommend ablation for drug-refractory atrial fibrillation.We aimed to prospectively analyze changes in cognitive function in patients with atrial fibrillation following treatment using different ablation methods.A total of 139 patients, with non-valvular atrial fibrillation, were included in the study. The patients were divided into the drug therapy (n = 41) and catheter ablation (n = 98) groups, with the catheter ablation group further subdivided into radiofrequency ablation (n = 68) and cryoballoon (CY) ablation (n = 30). We evaluated cognitive function at baseline, 3- and 12-months follow-up using the Telephone Interview for Cognitive Status-modified (TICS-m) test, then analyzed differences in cognitive function between the drug therapy and catheter ablation groups, to reveal the effect of the different ablation methods.We observed a significantly higher TICS-m score (39.56 ±â€Š3.198) in the catheter ablation group at 12-month follow-up (P < .001), than the drug treatment group was. Additionally, we found no statistically significant differences in TICS-m scores between the radiofrequency ablation and CY groups at 3- and 12-month postoperatively (P > .05), although the two subgroups showed statistically significant cognitive function (P < .001).Overall, these findings indicated that radiofrequency and CY ablation improve cognitive function in patients with atrial fibrillation.