Myocardial Activity at 18F-FAPI PET/CT and Risk for Sudden Cardiac Death in Hypertrophic Cardiomyopathy.

Background Myocardial fibrosis contributes to adverse cardiovascular events in hypertrophic cardiomyopathy (HCM). Purpose To explore the characteristics of cardiac fibroblast activation protein inhibitor (FAPI) PET/CT imaging and its relationship with the risk of sudden cardiac death (SCD) in HCM. Materials and Methods In this prospective study from July 2021 to January 2022, participants with HCM and healthy control participants underwent cardiac fluorine 18 (18F)-labeled FAPI PET/CT imaging. Myocardial FAPI activity was quantified as intensity (target-to-background uptake ratio), extent (the percent of FAPI-avid myocardium of the left ventricle [LV]), and amount (the percent of FAPI-avid myocardium of LV × target-to-background ratio). Regional wall thickness was analyzed at cardiac MRI. The 5-year SCD risk score was calculated from the 2014 European Society of Cardiology guidelines. Univariable and multivariable linear regression analyses were used to identify factors related to the FAPI amount. The correlation between FAPI amount and 5-year SCD risk was explored. Results Fifty study participants with HCM (mean age, 43 years ± 13 [SD]; 32 men) and 22 healthy control participants (mean age, 45 years ± 17; 14 men) were included. All participants with HCM had intense and inhomogeneous cardiac FAPI activity in the LV myocardium that was higher than that in healthy control participants (median target-to-background ratio, 8.8 vs 2.1, respectively; P < .001). In HCM, more segments with FAPI activity were detected than the number of hypertrophic segments (median, 14 vs five, respectively; P < .001); 84% of nonhypertrophic segments showed FAPI activity. Log-transformed FAPI amount had a positive relationship with log-transformed N-terminal probrain natriuretic peptide, high-sensitive troponin I, and left atrial diameter and a negative relationship with LV ejection fraction z-score. Degree of FAPI activity positively correlated with the 5-year SCD risk score (r = 0.32; P = .03). Conclusion Fibroblast activation protein inhibitor (FAPI) PET/CT imaging indicated intense and heterogeneous activity in hypertrophic cardiomyopathy, and FAPI uptake was associated with 5-year risk of sudden cardiac death. © RSNA, 2022 Online supplemental material is available for this article.

Left ventricular basal muscle bundle in hypertrophic cardiomyopathy: insights into the mechanism of left ventricular outflow tract obstruction.

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.

Myocardial bridging of the left anterior descending coronary artery as a risk factor for atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy: a matched case-control study.

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.

Risk Factors of Pulmonary Arterial Hypertension and Its Relationship With Atrial Fibrillation in Patients With Obstructive Hypertrophic Cardiomyopathy.

Background: Pulmonary arterial hypertension (PH) is a common complication in patients with obstructive hypertrophic cardiomyopathy (OHCM). The risk factor of PH in patients with OHCM has not been fully elucidated, and even atrial fibrillation (AF) was considered a risk factor of PH. Thus, our study aimed to investigate risk factors of PH and the relationship between PH and AF in patients with OHCM. Methods: We retrospectively enrolled 483 consecutive patients diagnosed with OHCM at Fuwai Hospital (Beijing, China) from January 2015 to December 2017. Clinical and echocardiographic parameters were compared between patients with and without PH. Results: Eighty-two (17.0%) patients were diagnosed with PH in this study. Compared to patients without PH, those with PH were significantly older, had a lower body mass index (BMI), were more likely to be female and more symptomatic [New York Heart Association Class 3 or 4 symptoms], and had a higher AF prevalence. A multivariate analysis indicated that AF was an independent risk factor of PH (odds ratio [OR] 2.31, 95% confidence interval [CI] 1.03-5.20, p = 0.042). Moreover, PH was independently associated with a higher AF incidence after adjusting for age and left atrial diameter (OR 2.24, 95% CI 1.07-4.72, p = 0.034). Conclusion: AF was independently associated with PH in patients with OHCM. Further, PH was significantly associated with an increased risk of AF, which suggested that AF could aggravate PH and that PH may promote AF processes, forming a vicious circle.

Mid-ventricular obstruction is associated with non-sustained ventricular tachycardia in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND: Mid-ventricular obstruction (MVO) is a rare subtype of hypertrophic cardiomyopathy (HCM) but it is associated with ventricular arrhythmia. The relationship between MVO and non-sustained ventricular tachycardia (NSVT) in HCM patients is unknown. HYPOTHESIS: The severity of MVO increases the incidence of NSVT in patients with hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Five hundred and seventy-two consecutive patients diagnosed with HOCM in Fuwai Hospital between January 2015 and December 2017 were enrolled in this study. Holter electrocardiographic and clinical parameters were compared between HOCM patients with and without MVO. RESULTS: Seventy-six (13.3%) of 572 patients were diagnosed with MVO. Compared to patients without MVO, those with MVO were much younger, and had a higher incidence of syncope, greater left ventricular (LV) posterior wall thickness, a higher percentage of LV late gadolinium enhancement, and higher prevalence of NSVT. Furthermore, the prevalence of NSVT increased with the severity of MVO (without, mild, moderate or severe: 11.1%, 18.2%, 25.6%, respectively, p for trend < .01). Similarly, the prevalence of NSVT differed among patients with isolated LV outflow tract (LVOTO), both MVO and LVOTO, and isolated MVO (11.1%, 21.3%, 26.6%, respectively, p for trend = .018). In addition to age, diabetes, left atrial diameter, and maximal wall thickness, multivariate analysis revealed the presence of MVO as an independent risk factor for NSVT (Odds ratio 2.69; 95% confidence interval 1.41 to 5.13, p = .003). CONCLUSIONS: The presence and severity of MVO was associated with higher incidence of NSVT in HOCM patients.

Validation of methods for effective orifice area measurement of prosthetic valves by two-dimensional and Doppler echocardiography following transcatheter self-expanding aortic valve implantation.

BACKGROUND: The effective orifice area (EOA) is utilized to characterize the hemodynamic performance of the transcatheter heart valve (THV). However, there is no consensus on EOA measurement of self-expanding THV. We aimed to compare two echocardiographic methods for EOA measurement following transcatheter self-expanding aortic valve implantation. METHODS: EOA was calculated according to the continuity equation. Two methods were constructed. In Method 1 and Method 2, the left ventricular outflow tract diameter (LVOTd) was measured at the entry of the prosthesis (from trailing-to-leading edge) and proximal to the prosthetic valve leaflets (from trailing-to- leading edge), respectively. The velocity-time integral (VTI) of the LVOT (VTILVOT) was recorded by pulsed-wave Doppler (PW) from apical windows. The region of the PW sampling should match that of the LVOTd measurement with precise localization. The mean transvalvular pressure gradient (MG) and VTI of THV was measured by Continuous wave Doppler. RESULTS: A total of 113 consecutive patients were recruited. The mean age was 77.2 ± 5.5 years, and 72 patients (63.7%) were male. EOA1 with the use of Method 1 was larger than EOA2 (1.56 ± 0.39 cm2 vs. 1.48 ± 0.41 cm2, P = 0.001). MG correlated better with the indexed EOA1 (EOAI1) (r = -0.701, P < 0.001) than EOAI2 (r = -0.645, P < 0.001). According to EOAI (EOAI ≤ 0.65 cm2/m2, respectively), the proportion of sever prosthesis-patient mismatch with the use of EOA1 was lower than EOA2 (12.4% vs. 21.2%, P < 0.05). Compared with EOA2, EOA1 had lower interobserver and intra-observer variability (intra: 0.5% ± 17% vs. 3.8% ± 22%, P < 0.001; inter: 1.0% ± 9% vs. 3.5% ± 11%, P < 0.001). CONCLUSIONS: For transcatheter self-expanding valve EOA measurement, LVOTd should be measured in the entry of the prosthesis stent (from trailing-to-leading edge), and VTILVOT should match that of the LVOTd measurement with precise localization.

Predictors of long-term outcome after septal myectomy in symptomatic hypertrophic obstructive cardiomyopathy patients with previous alcohol septal ablation and residual obstruction.

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.

Obstructive sleep apnea causes impairment of the carotid artery in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND: Obstructive sleep apnea (OSA) prevalence is high among patients with hypertrophic cardiomyopathy (HCM). OSA can cause increase in carotid intima-media thickness (CIMT) in the general population. However, whether this phenomenon is applicable to patients with HCM is unclear. METHODS: A total of 130 consecutive patients with a confirmed diagnosis of hypertrophic obstructive cardiomyopathy (HOCM) at Fuwai Hospital between September 2017 and May 2018 were analyzed. RESULTS: 72 patients (55.4%) were diagnosed with OSA. Patients with OSA were older. Compared to those in patients without OSA, the left, right, and mean CIMTs were significantly increased in patients with OSA. In the multiple linear regression model, age (ß = 0.341, p < 0.001), apnea-hypopnea index (AHI) (ß = 0.421, p < 0.001), and fasting glucose level (ß = 0.167, p < 0.03) were independently associated with mean CIMT increase (adjusted R2 = 0.458, p < 0.001). In the receiver operating characteristic curve analysis, the area under the curve for CIMT was 0.813 (95% CI, 0.717-0.909, p < 0.001) with a sensitivity and specificity of 0.84 and 0.70 for unexplained syncope, respectively. In the multivariate logistic regression model, we found that the mean CIMT (OR = 10.4, 95% CI = 3.16-34.11, p < 0.001), left ventricular ejection fraction (LVEF) (OR = 0.90, 95% CI = 0.83-0.99, p = 0.03), and amaurosis (OR = 5.07, 95% CI = 1.47-17.49, p = 0.01) were independently associated with unexplained syncope occurrence. CONCLUSIONS: In patients with HOCM, CIMT increased with OSA severity. Age, AHI, and fasting plasma glucose level were independently associated with mean CIMT increase. Moreover, amaurosis, LVEF, and higher mean CIMT were independently associated with unexplained syncope in patients with HOCM.

Incidence and predictors of asymptomatic pericardial effusion after transcatheter closure of atrial septal defect.

AIMS: Pericardial effusion (PE) without obvious periprocedural complications (e.g., cardiac perforation, device erosion) may occur after transcatheter closure of secundum atrial septal defects (ASD). The aim of the study was to investigate the incidence and predictors of PE unrelated to procedural complications. METHODS AND RESULTS: We included all patients who had undergone successful percutaneous ASD closure from June 2009 to April 2014 (n=2,652) with no pre-existing PE or cardiac perforation or erosion. Transthoracic echocardiography (TTE) was performed during the procedure and one, three, and six months postoperatively. After device implantation, fifty patients (1.9%) developed new-onset PE (37 immediately, 13 during follow-up). These patients were asymptomatic, stable haemodynamically, and had no new arrhythmias. PE appeared mild (5.1±1.9 mm) and homogeneously echolucent by TTE. PE diminished spontaneously. Compared with 2,602 patients without PE, factors independently predicting asymptomatic PE were the device touching the atrial free wall, device size, patient age, and total defect size. Areas under the receiver operating characteristic curves were 0.78 (p<0.001), 0.66 (p<0.001) and 0.77 (p<0.001) for device size, patient age, and total defect size, respectively. CONCLUSIONS: This is the first systematic report of a new type of PE. Our data provide new insights into new-onset PE after percutaneous ASD closure.

Excision of anomalous muscle bundles as an important addition to extended septal myectomy for treatment of left ventricular outflow tract obstruction.

OBJECTIVE: This study aims to report our preliminary experience and anatomic findings in the surgical treatment and postoperative management of hypertrophic obstructive cardiomyopathy. METHODS: This study included 277 patients with hypertrophic obstructive cardiomyopathy (168 [60.65%] were male), with a median age of 47 years (interquartile range, 35-54 years), who underwent surgical myectomy performed by 1 surgeon in Fuwai Hospital between May 2010 and April 2015. The median follow-up was 14 months (interquartile range, 7-24 months). RESULTS: A total of 127 patients (45.85%) underwent concomitant procedures, and 2 patients (0.72%) died in the early perioperative days. The left ventricular outflow gradient decreased from 78 mm Hg (interquartile range, 61-100 mm Hg) to 11 mm Hg (interquartile range, 8-15 mm Hg) when discharged (P < .001). Of the 228 patients with well-documented anatomic description, more than 80% had various intraventricular anomalies. The cumulative survival was 99.28% (95% confidence interval, 97.15-99.82) at 1 year and 96.98% (95% confidence interval, 92.56-98.79) at 5 years. Of the surviving 272 patients, 268 (98.53%) were categorized with functional class I and II of the New York Heart Association classification at the latest evaluation. CONCLUSIONS: Anomalous muscle bundles are common in hypertrophic obstructive cardiomyopathy, and they may lead to middle-apical obstruction. Surgical myectomy provides excellent clinical outcomes with low risk for sufficient relief of obstruction and radical correction of intraventricular anomalies in patients with hypertrophic obstructive cardiomyopathy.

Regional Left Ventricular Reverse Remodeling After Myectomy in Hypertrophic Cardiomyopathy.

BACKGROUND: Surgical extended septal myectomy is appropriate treatment for obstructive hypertrophic cardiomyopathy (HCM) with refractory symptoms. Using 3-layer speckle tracking imaging, we aimed to evaluate the effects of myectomy on left ventricular (LV) regions and the potential factors associated with LV reverse remodeling. METHODS: In 71 patients (mean age, 41.0 ± 15.0 years) undergoing septal myectomy, 3-layer speckle tracking was performed before myectomy and latest review. We evaluated the myectomy site (target anteroseptum) and LV free wall longitudinal strain (LS) and circumferential strain (CS) in endocardial, midmyocardial, and epicardial layers. The thickness of each free wall segment was calculated and totaled for the free wall thickness score. RESULTS: Compared with before myectomy, LS increased; however, CS decreased at the myectomy site after myectomy. For the free wall, LS and CS improved in all 3 layers after the procedure (all p < 0.05). Factors independently associated with latest-review free wall strain were free wall thickness score (LS, ß = -0.150; p < 0.001; CS, ß = -0.090; p < 0.001), age (LS, ß = 0.118; p < 0.001), and ΔLV outflow tract gradient (CS, ß = 0.039; p = 0.002). Factors independently associated with myectomy site strain were resected thickness (LS, ß = -0.439; p = 0.001; CS, ß = -0.736; p = 0.001), and age (LS, ß = 0.178; p < 0.001). CONCLUSIONS: Sufficient relief of obstruction and lower resected thickness in the target anteroseptum lead to more favorable remodeling. Free wall thickness score and age are important factors associated with reverse remodeling.

Assessment of the morphology and mechanical function of the left atrial appendage by real-time three-dimensional transesophageal echocardiography.

BACKGROUND: The left atrial appendage (LAA) is an important source of thrombus formation. We investigated the feasibility of the recently developed real-time three-dimensional transesophageal echocardiography (RT3D-TEE) method in assessment of the morphology and function of the LAA. METHODS: Ninety-six consecutive patients (58 males with a mean age of (43.4 ± 12.5) years) who were referred for 2-dimensional (2D) transesophageal echocardiography (TEE) underwent additional RT3D-TEE. LAA morphology was visualized in multiple views. Orifice size, depth, volumes and ejection fraction (EF) of the LAA, were measured. RESULTS: All the patients underwent RT3D-TEE examination without complications. Ninety-two patients (95.8%) had adequate images for visualization and quantitative analysis of the LAA. The LAA exhibited great variability with respect to relative dimensions and morphology. LAA orifice area was (3.8 ± 1.2) cm(2) with a diameter of (2.4 ± 0.9) cm × (1.4 ± 0.6) cm. The mean depth of the LAA was (2.9 ± 0.7) cm. End-diastolic volume (EDV-LAA), end-systolic volume (ESV-LAA) and EF of the LAA were (6.2 ± 3.7) ml, (4.1 ± 2.8) ml, and 0.35 ± 0.16, respectively. EDV-LAA, ESV-LAA and the orifice area of the LAA in patients with atrial fibrillation (AF) were larger than those without AF, whereas the EF was smaller in the AF patients. CONCLUSIONS: Defining LAA morphology and quantitative analysis of the size and function of the LAA with superior quality and resolution of images using RT3D-TEE is feasible. This technique may be an ideal tool for guidance of the LAA occlusion procedure. Determination of LAA volumes and volume-derived EF by RT3D-TEE provides new insights into the analysis of LAA function.