Cardiac Scintigraphy With Technetium-99m-Labeled Bone-Seeking Tracers for Suspected Amyloidosis: JACC Review Topic of the Week

Technetium-labeled cardiac scintigraphy (i.e., Tc-PYP scan) has been repurposed for the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). Validated in cohorts of patients with heart failure and echocardiographic and/or cardiac magnetic resonance imaging findings suggestive of cardiac amyloidosis, cardiac scintigraphy can confirm the diagnosis of ATTR-CM only when combined with blood and urine testing to exclude a monoclonal protein. Multisocietal guidelines support the nonbiopsy diagnosis of ATTR-CM using cardiac scintigraphy, yet emphasize its use in the appropriate clinical context and the crucial need to rule out light chain amyloid cardiomyopathy. Although increased awareness of ATTR-CM and the advent of effective therapy have led to rapid adoption of diagnostic scintigraphy, there is heterogeneity in adherence to consensus guidelines. This perspective outlines clinical scenarios wherein findings on technetium-labeled cardiac scintigraphy have been misinterpreted, reviews causes of false-negative and false-positive results, and provides strategies to avoid costly and potentially fatal misdiagnoses.     

MN9202对心肌细胞的收缩和舒张功能的影响

目的研究MN9202对心肌细胞收缩舒张功能的影响.方法采用IonOptix单细胞动缘检测系统(IonOptix Co.USA),测定心肌细胞收缩幅度和收缩/舒张速度等,这些指标均由计算机自动实时采集并记录.结果MN9202降低心肌收缩幅度(ph)、心肌细胞收缩幅度/单个心肌细胞的长度百分比(peak height/baseline×100%,ph/bl%)、最大收缩速率( dL/dt)和最大舒张速率(-dL/dt),ph在对照组、MN9202(3×10-6mol/L)组和拉西地平(lacidipine,3×10-6mol/L)组分别为(0.13±0.04)μm、(0.08±0.05)μm和(0.07±0.04)μm,ph/bl%分别为(8.6±2.8)%、(5.8±4.3)%和(5.6±3.3)%, dL/dt分别为(1.6±0.5)μm/s、(1.1±0.7)μm/s和(1.0±0.6)μm/s,-dL/dt分别为(1.2±0.4)μm/s、(0.8±0.3)μm/s和(0.7±0.3)μm/s.异丙肾上腺素(10-8mol/L,isoproterenol,Iso)增加ph、pl/bl%、 dL/dt和-dL/dt均有统计学意义,上述指标分别增加45%、47%、54%、78%.3×10-7mol/L的MN9202和拉西地平降低Iso引起ph、ph/bl%、 dL/dt和-dL/dt的升高,其中MN9202使 dL/dt和-dL/dt的降低较对照组有显著差异(P＜0.05),拉西地平使ph/bl%、 dL/dt和-dL/dt的降低较对照组有统计学意义.结论MN9202使心肌细胞收缩和舒张功能均降低;Iso所致心肌细胞收缩和舒张功能的增强,3×10-7mol/L MN9202和拉西地平有抑制Iso的作用.     

Effect of propranolol on ventricular repolarization and refractoriness: Role of beta-blockade versus direct membrane effects

Summary The purpose of this study was to define the role of beta-adrenergic blockade and direct membrane effects in the ability of dl-propranolol to alter ventricular repolarization and refractoriness in the intact heart. The effective refractory period (ERP) and the local Q-T interval were measured at an epicardial site in the left ventricle in 14 open-chest dogs anesthetized with alpha-chloralose. Beta-adrenergic influences were eliminated in seven dogs (group 1) by stellate transection and nadolol (0.5 mg/kg IV), and enhanced in seven dogs (group 2) by stellate transection and stimulation of the left ansae subclavia. Each dog received an initial beta-blocking dose of propranolol (0.5 mg/kg) followed by a second, cumulative dose of 5.0 mg/kg. In group 1 dogs, there was no significant change in either the ERP or local Q-T interval in response to the first dose of propranolol. In group 2 dogs, left stellate stimulation significantly shortened the ERP (20±2 msec) and the local Q-T interval (17±4 msec). The first dose of propranolol prolonged these parameters to values not different from prestimulation control values. There was no change in the H-V interval, QRS complex duration, or diastolic threshold (DT) in either group after the initial propranolol dose. The second dose of propranolol significantly shortened the ERP (5±1 msec) and the local Q-T interval (11±2 msec) in both groups. This dose also significantly increased the DT, H-V interval, and QRS complex duration. In three additional nadolol-treated dogs, a single 5 mg/kg dose of propranolol shifted the entire strength-interval curve 4 to 7 msec earlier into electrical diastole. The data indicate that a beta-blocking dose of propranolol prolongs repolarization and refractoriness only when adrenergic input is elevated. In the absence of beta-adrenergic influences, high doses of propranolol shorten repolarization and refractoriness. This latter effect may be due to a direct membrane effect of the drug.     

25 years of aortic valve replacement using mechanical valves: Risk factors for early and late mortality

This study describes the changes that have taken place in patientcharacteristics in 25 years of aortic valve replacement usingmechanical valves, and looks for risk factors for early andlate mortality. During this period, 1449 mechanical valves wereimplanted. Overall early mortality (<30 days) was 5·3%and for aortic valve replacement without concomitant procedures3·9%. Overall survival rates at 5, 10 and 15 years were80%, 63% and 49%, respectively. Despite an increased proportionof higher risk patients (older age, more reoperations, moreconcomitant coronary bypass surgery) survival rates improvedthroughout the study period. Early mortality was related toan early year of operation, urgency, reoperation and concomitantsurgery to the tricuspid valve or ascending aorta. Late mortalitywas higher for patients of older age, with an early year ofoperation, male gender, concomitant coronary bypass surgery,mitral valve surgery or replacement of the ascending aorta.Aortic regurgitation did not have a major influence on earlynor late mortality. The improvement in early and late mortalityin more recent years was largely the result of the introductionof cardioplegia. A changing, non-proportional effect was observedfor several risk factors during the follow-up period. This studyillustrates the changes and improvements in medical care thathave taken place in patients requiring aortic valve replacement.     

机械瓣膜置换术后低强度抗凝的初步研究

将50名风显性心脏瓣膜病患者按国际标准化比值（INR）分为三组，并于术后定时分别检测凝血酶原时间（PT）及相应的INR，D－二聚体（D-dimer)浓度，抗凝血酶Ⅲ活度（AT－Ⅲ：C），并监测其术后出血及血栓形成发生率。结果：机械瓣膜置换术（HVR）后，INR控制于1．3－2．0范围内即可保持D－dimer浓度，AT－Ⅲ：C，与对照组无显著差异（P＞0．01）。采取高的INR值虽可以降低D－dimer浓度，提高AT－Ⅲ：C，但差异不显著（P＞0．01），而出血发生概率明显增加（P＜0．01）。三组术后并未出现血栓形成，说明风湿性心脏瓣膜病患者机械瓣膜置换术后行低强度抗凝是可行的，术后采取INR控制于1．3－2．0的低强度抗凝是安全的。     

Transcatheter perforation of atretic pulmonary valve by the stiff end of a coronary wire in neonates with pulmonary atresia with intact ventricular septum: A solution in developing countries

Objectives

To evaluate the safety of using the stiff end of a coronary wire to perforate an atretic pulmonary valve (PV) in patients with pulmonary atresia with intact ventricular septum (PAIVS).

A novel use of a split sheath to maintain vessel access when guidewire exchange is not possible

After inserting a catheter into a vessel, guidewire exchange technique must be used to maintain vascular access. If the lumen of the catheter is blocked and the guidewire exchange cannot be used, the catheter can only be removed, vascular access is lost, and an alternate vascular approach attempted. We describe a technique to remove the blocked catheter and still maintain vascular access. © 2008 Wiley‐Liss, Inc.     

Myocardial Fibrosis and Inflammation by CMR Predict Cardiovascular Outcome in People Living With HIV

ObjectivesThe goal of this study was to examine prognostic relationships between cardiac imaging measures and cardiovascular outcome in people living with human immunodeficiency virus (HIV) (PLWH) on highly active antiretroviral therapy (HAART).BackgroundPLWH have a higher prevalence of cardiovascular disease and heart failure (HF) compared with the noninfected population. The pathophysiological drivers of myocardial dysfunction and worse cardiovascular outcome in HIV remain poorly understood.MethodsThis prospective observational longitudinal study included consecutive PLWH on long-term HAART undergoing cardiac magnetic resonance (CMR) examination for assessment of myocardial volumes and function, T1 and T2 mapping, perfusion, and scar. Time-to-event analysis was performed from the index CMR examination to the first single event per patient. The primary endpoint was an adjudicated adverse cardiovascular event (cardiovascular mortality, nonfatal acute coronary syndrome, an appropriate device discharge, or a documented HF hospitalization).ResultsA total of 156 participants (62% male; age [median, interquartile range]: 50 years [42 to 57 years]) were included. During a median follow-up of 13 months (9 to 19 months), 24 events were observed (4 HF deaths, 1 sudden cardiac death, 2 nonfatal acute myocardial infarction, 1 appropriate device discharge, and 16 HF hospitalizations). Patients with events had higher native T1 (median [interquartile range]: 1,149 ms [1,115 to 1,163 ms] vs. 1,110 ms [1,075 to 1,138 ms]); native T2 (40 ms [38 to 41 ms] vs. 37 ms [36 to 39 ms]); left ventricular (LV) mass index (65 g/m² [49 to 77 g/m²] vs. 57 g/m² [49 to 64 g/m²]), and N-terminal pro–B-type natriuretic peptide (109 pg/l [25 to 337 pg/l] vs. 48 pg/l [23 to 82 pg/l]) (all p < 0.05). In multivariable analyses, native T1 was independently predictive of adverse events (chi-square test, 15.9; p < 0.001; native T1 [10 ms] hazard ratio [95% confidence interval]: 1.20 [1.08 to 1.33]; p = 0.001), followed by a model that also included LV mass (chi-square test, 17.1; p < 0.001). Traditional cardiovascular risk scores were not predictive of the adverse events.ConclusionsOur findings reveal important prognostic associations of diffuse myocardial fibrosis and LV remodeling in PLWH. These results may support development of personalized approaches to screening and early intervention to reduce the burden of HF in PLWH (International T1 Multicenter Outcome Study; NCT03749343).     

糖尿病大鼠心力衰竭时心肌细胞凋亡的研究

目的探讨糖尿病大鼠心力衰竭时是否存在心肌细胞凋亡.方法建立STZ糖尿病大鼠模型,饲养12周,经心功能检测后确认为糖尿病心力衰竭的大鼠,采用TUNEL法及TEM法,检测糖尿病大鼠左室心肌的凋亡细胞.结果 糖尿病大鼠出现心功能异常并可见凋亡的心肌细胞,而对照组左室心肌组织中未见心肌细胞凋亡.结论心肌细胞凋亡与糖尿病大鼠心力衰竭密切相关.     

体外无创性临时心脏起搏的临床应用

目的　评价体外无创性临时心脏起搏 ( ENCP)对心脏骤停及急性严重缓慢性心律失常的抢救效果、安全性。方法　 19例心脏骤停患者和 18例有严重临床症状缓慢性心律失常患者紧急行 ENCP。结果　所有病人均在 1～ 5 min内在床边得到 ENCP。心脏骤停组 12例起搏成功 ,其中 5例复苏 ,起搏成功者平均起搏阈值 ( 10 5 .2± 15 .6) m A,起搏成功率 63 .1% ,起搏成功并复苏2 6.3 %。严重缓慢性心律失常组 17例 ENCP后临床症状迅速明显改善 ,平均起搏阈值 ( 75 .3± 2 1.5 ) m A,起搏成功率 94.4%。严重缓慢性心律失常组的起搏成功率明显高于心脏骤停组 ,起搏阈值明显低于心脏骤停组。所有患者起搏过程中均出现与起搏脉冲同步的胸部肌肉抽动 ,但只有 1例因胸痛在 ENCP维持下安装了经静脉临时心脏起搏器 ,其余病人虽有不适 ,均能接受 ENCP。所有 ENCP患者均未发现皮肤、软组织损伤及严重心律失常等不良反应。结论　体外起搏是心脏骤停、急性严重缓慢性心律失常行之有效的治疗手段。