Hemodynamic effects of isometric exercise in hypertrophic cardiomyopathy: Comparison with normal subjects

BACKGROUND: We assessed the hemodynamic effects of isometric exercise by an ambulatory radionuclide monitoring device (VEST) that measured left ventricular function in patients who had hypertrophic cardiomyopathy (HCM), with and without significant left ventricular outflow-tract obstruction at rest, compared with control subjects. METHODS AND RESULTS: We studied 10 patients with obstructive HCM, 25 patients with nonobstructive HCM, and 11 control subjects. During VEST monitoring, all patients gripped a dynamometer at 75% of maximal strength for up to 5 minutes. End-diastolic, end-systolic, and stroke volumes; cardiac output; and systemic vascular resistance were expressed as a percentage of baseline. The mean exercise duration was similar among the 3 groups. During handgrip, heart rate, systolic blood pressure, and cardiac output increased significantly and similarly in the 3 groups. There was a significant difference in the lung activity between obstructive and nonobstructive HCM patients and control subjects (P <.001), with a fall in control subjects and no change in HCM patients, irrespective of obstruction. Control subjects showed a decrease in end-systolic volume (P =.02) and an increase in ejection fraction (P =.003) and stroke volume (P =.009), whereas these parameters did not change in HCM patients, irrespective of obstruction. Systemic vascular resistance increased in obstructive (P =.02) and nonobstructive (P <.01) HCM patients but did not change in control subjects. CONCLUSIONS: Isometric exercise causes an abnormal and similar adaptation to load changes in obstructive and nonobstructive HCM patients, as compared with control subjects.     

肥厚性心肌病MR延迟增强与心肌钙蛋白Ⅰ相关性的初步研究

目的：初探肥厚性心肌病（HCM）心肌MR延迟增强（DE）与心肌钙蛋白Ⅰ（cTn Ⅰ）的相关性，以及二者联合用于评价HCM病情和提示预后的价值。方法：搜集经超声心动图诊断的HCM患者35例，均同期行MR检查和血cTn Ⅰ检测，分析MR延迟增强与心肌肥厚、cTn Ⅰ值改变的关系。结果：（1）35例HCM中出现MR心肌灌注延迟期强化者25例（71．4％），血cTn Ⅰ异常增高者19例。无DE组cTn Ⅰ中位值5μg／L，DE组cTn Ⅰ中位值110μg／L，2组之间差异有统计学意义（U=-2．618，P〈0．05）。DE组25例中有18例（72．0％）血cTn Ⅰ异常增高，而在19例血cTn Ⅰ异常增高者中18例（94．7％）出现延迟强化。（2）心肌增强比例与肥厚比例呈正相关（rs=0．713，P〈0．01）。cTn Ⅰ值与心肌肥厚比例、增强比例呈正相关（rs=0．521、0．605，P均〈0．01）。结论：心肌MRI延迟增强和血cTn Ⅰ异常升高常同时发生于HCM患者。MR心肌延迟强化成像与cTn Ⅰ检测联合应用可以为准确判断HCM病情、评价疗效及预后提供有效的信息。     

基因突变阳性肥厚型心肌病患者超声心动图表现初步探讨

目的:初步探讨基因突变阳性肥厚型心肌病超声心动图的特点.方法:通过基因检测筛选出肥厚型心肌病患者基因突变阳性者,应用超声心动图观察患者室壁厚度、房室内径,并且通过多普勒组织成像观察患者心脏功能.结果:检测出肥厚型心肌病基因突变阳性患者5例,突变结果分别为β-MyHC、MyBP-C、TnT编码基因突变.超声表现均为左室壁为非对称性肥厚,均为非梗阻性肥厚型心肌病,都表现出左室舒张功能减低.结论:二维超声心动图能够描述肥厚型心肌病患者心脏结构变化,多普勒组织成像能够敏感的发现肥厚型心肌病基因突变患者心功能改变.MyHC左室舒张功能减低最明显.     

肥厚型心肌病合并心律失常临床特征及治疗

目的探讨肥厚型心肌病合并心律失常的临床特征及治疗方法。方法回顾性分析2000年9月至2016年7月经心脏超声或左室造影及心电图或动态心电图证实为肥厚型心肌病(HCM)合并心律失常的105例患者临床特征及治疗方法。结果 105例患者分为肥厚型非梗阻性心肌病组(HNCM)42例,肥厚型梗阻性心肌病组(HOCM)41例,心尖肥厚型心肌病组(AHCM)22例。3组患者临床特征差异无统计学意义(P>0.05)。HCM合并心律失常类型包括窦性心动过缓、心房扑动、心房颤动、房室传导阻滞、频发房性早搏、频发室性早搏、非持续性室性心动过速、心室颤动。3组不同心律失常类型中,均为心房颤动发生率最高,分别为38.1%、63.4%及50.0%。HOCM组12例患者行经皮间隔心肌消融术,4例患者行外科肥厚心肌切除术。HNCM组4例患者行永久起搏器植入术。HOCM组2例患者因心室颤动植入单腔植入型心律转复除颤器。HNCM组、HOCM组及AHCM组分别有7例、2例及2例患者行射频消融术。出院后随访3~14个月,平均(8±3)个月,患者均存活,临床症状均明显缓解。结论 HCM合并心律失常的患者,选择适当的治疗方法,可取得良好的疗效。     

Abnormal left ventricular ejection fraction response to mental stress and exercise in cardiomyopathy

Background

A decline in left ventricular (LV) ejection fraction in response to mental stress and exercise is regarded as an indicator of myocardial ischemia. In patients with LV dysfunction, the ejection fraction is sensitive to afterload, which increases during stress. Thus, the effects of mental stress and exercise on LV systolic function in patients with cardiomyopathy were examined.

Methods

The ambulatory nuclear VEST (Capintec, Inc., Ramsey, N.J.) was used to monitor LV ejection fraction in patients with cardiomyopathy (10 idiopathic and 9 ischemic). Patients underwent a series of mental stress tests (serial 7s, Stroop color, and Paced auditory addition) and treadmill exercise. Heart rate, systolic blood pressure, and LV ejection fraction were measured.

Results

Mental stress and exercise increased heart rate and systolic blood pressure. For idiopathic cardiomyopathy, LV ejection fraction decreased during serial 7s, Stroop color, Paced auditory addition and exercise by ?8%±6%, ?7%±5%, ?7%±3%, ?9%±10%, respectively. For ischemic cardiomyopathy, LV ejection fraction declined by ?4%±3%, ?7%±5%, ?6%±3%, ?2%±6% during the same stress tests. There was no difference between the idiopathic and ischemic groups. Each patient showed a 5% or greater decline in LV ejection fraction during one mental stress test. There was an inverse relation between changes in LV ejection fraction and systolic blood pressure during all mental stress tests and exercise (r=?0.47, p<0.0001).

Conclusions

In patients with depressed baseline systolic function, the decline in systolic function during mental stress and exercise could be related in part to increases in LV afterload.     

儿童肥厚型心肌病磁共振延迟强化特征分析

目的分析肥厚型心肌病（HCM）患儿心脏受累心肌MRI对比剂延迟强化发生率及其与预后的相关性。方法收集2006年1月至2012年1月我院收治的HCM患儿71例,所有患儿均接受心脏MRI检查,并行对比剂增强心肌显像。根据左心室心肌是否存在延迟强化,将患儿分为延迟强化组和非延迟强化组,并进一步分析受累心肌对比剂延迟强化的范围及程度等。应用Kaplan-Meier生存曲线分析两组患儿的预后差别,两组临床数据间的统计分析采用t检验。结果71例HCM患儿中,9例（12.7%）患儿左心室为对称性肥厚,其中2例患儿进展至终末期。52例（73%）患儿出现心肌延迟强化,其延迟强化组患儿左心室质量高于非延迟强化组患儿[（112.7±57.9）g/m2 vs.（70.3±37.4）g/m2],两组间差异有统计学意义（t=2.71,P=0.025）;但两组左室室壁厚度[（19.4±6.3）mm/m2 vs.（18.1±7.9）mm/m2]比较,差异无统计学意义（t=0.69,P=0.513）。HCM患儿随访（2.4±1.6）年显示,心肌延迟强化与不良心血管事件的发生密切相关（χ2=4.77,P=0.029）。结论HCM患儿中,其心肌延迟强化发生率与成人患者接近,并且心肌延迟强化具有判断患儿预后的临床价值。     

Effects of exercise on the duration of diastole and on interventricular phase differences in patients with hypertrophic cardiomyopathy: relationship to cardiac output reserve

Background  Our study sought to characterize the effect of exercise on the duration of left ventricular (LV) diastole and interventricular dyssynchrony in patients with hypertrophic cardiomyopathy (HCM). We hypothesized that an abnormally shortened diastolic time may adversely affect cardiac performance. Methods  We studied 49 symptomatic patients with HCM during incremental exercise. Twenty-nine patients had obstructive disease (HOCM) and 20 no resting or provocable gradient (HNCM). Right heart catheterization and high temporal resolution radionuclide angiography were simultaneously performed. The loss of diastolic time per beat (LDT_RR) was quantified using a regression equation obtained from a healthy control group (n = 30). Results  During rest and peak exercise, a significant shortening of the relative duration of LV diastole (35.6 ± 5 vs. 38.0 ± 3 s/min and 29.3 ± 6 vs. 32.4 ± 3 s/min; P ≤ .02) and an increased interventricular phase delay were evident in patients with HOCM compared to controls. Baseline and peak exercise LDT_RR values were inversely related to cardiac output reserve and exercise duration. In multivariate analysis, LDT_RR at peak exercise was identified as an independent predictor of cardiac output reserve. Conclusions  In HOCM, baseline abnormalities of the relative duration of LV systolic and diastolic time aggravate during exercise. The disproportionate shortening of diastolic time may significantly impair cardiac efficiency by restricting diastolic filling.     

Effects of diltiazem on myocardial perfusion abnormalities during exercise in patients with hypertrophic cardiomyopathy

The effect of diltiazem on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise myocardial²⁰¹Tl single photon emission computed tomography (SPECT). Exercise myocardial SPECT was performed before and 8 weeks after oral administration of diltiazem (180 mg/day) in 20 patients with HCM who showed transient perfusion defects on exercise myocardial²⁰¹Tl SPECT under control conditions. SPECT images were divided into 17 segments. The²⁰¹Tl perfusion defects were visually scored and evaluated as the defect score. The transient dilation index was calculated as an index of subendocardial ischemia. Improvement of the defect score was demonstrated in 15 patients after the administration of diltiazem. The mean defect score decreased significantly from 9.90± 5.17 to 5.50±4.89 (p < 0.0001). Although 16 of 20 patients showed an abnormal transient dilation index before diltiazem treatment, 16 showed improvement and 13 of these normalized after diltiazem therapy. The mean transient dilation index decreased from 1.16 + 0.10 to 1.02 ± 0.09 (p < 0.0001). In conclusion, diltiazem prevents or diminishes myocardial ischemia in patients with HCM.     

肥厚型心肌病的心电图分析

目的探讨肥厚型心肌病的患者心电图变化及其临床意义。方法对超声心动诊断的88例肥厚型心肌病患者均行常规12导联心电图检查,并对其进行分析。结果心电图异常（ST-T改变、异常Q波、心室肥厚等）发生率为93．2％。Ⅳ型ST—T改变多见于前侧壁导联（V1～V3）、高侧壁导联（I～avL）,具有特殊性。其他3型患者ST-T改变、异常Q波的发生率及部位差异均无统计意义（P〈0．05）。结论肥厚型心肌病患者大多存在不同程度的心电图异常,但除心尖肥厚型心肌病外,其他各型心电图改变没有特异性。     

细胞凋亡抑制因子在心肌病血清中的表达

 目的探讨细胞凋亡抑制因子对心肌病的影响和作用机制.方法运用细胞免疫学方法,检测了66例心肌病患者细胞凋亡抑制因子APO-1/Fas和调节因子IL-6,TNFa等指标.结果心肌病各组APO-1/Fas,IL-6,TNFa等指标较对照组有不同程度升高,心功能愈差,升高愈明显.结论 APO-1/Fas,IL-6,TNFa等细胞凋亡抑制因子在心肌病细胞凋亡病变中有明显抑制或调节作用.     

Norepinephrine alters exercise oxygen consumption in heart failure patients

PURPOSE: The primary aim of this research was to evaluate the effect of acute norepinephrine (NE) infusion on the exercise oxygen utilization in heart failure patients as compared with healthy adults. METHODS: Eleven healthy adults and 10 patients with NYHA class II-III heart failure (ejection fraction <40%) who were not on beta-blocker therapy underwent steady state exercise under placebo or NE infusion conditions, followed by maximal ramp exercise testing. Oxygen utilization, hemodynamic responses, and serum lactate NE levels were evaluated. RESULTS: The hemodynamic effects of NE were evident in both groups with statistically significant increases in blood pressure and concomitant decreases in heart rates. Lactate levels were higher in heart failure subjects under all conditions and steady state exercise increased levels by 24% (P = 0.04). NE infusion increased lactate levels by a nonsignificant 24% (P = 0.19). NE infusion tended to increase oxygen consumption (VO2) at the end of steady state exercise in CHF subjects (4% change; P = 0.06). Compared with healthy adults, NE infusion significantly impaired (increased) the gross VO2/W relationship in heart failure subjects (P = 0.037). There was also a modest trend for a worsening (decrease) in net efficiency after NE infusion in CHF subjects. There were no significant adverse effects of low-dose NE infusion in either group. CONCLUSIONS: We conclude that 1) acute low-dose NE infusion impairs the oxygen utilization in stable heart failure patients but not in healthy adults. This may help to explain the exercise intolerance that accompanies congestive heart failure. 2) Acute infusion of low-dose NE infusion is safe and well tolerated in both healthy adults and compensated heart failure patients.     

Reverse redistribution of Tc-99m-tetrofosmin in exercise myocardial SPECT in patients with hypertrophic cardiomyopathy

We examined the usefulness of Tc-99m-tetrofosmin in detecting exercise induced perfusion abnormalities in patients with hypertrophic cardiomyopathy (HCM) and to clarify time-related changes in myocardial distribution of Tc-99m-tetrofosmin after a single injection. We studied 44 consecutive patients with HCM by means of exercise/rest Tc-99m-tetrofosmin single photon emission computed tomography (SPECT). After injecting 370 MBq of Tc-99m-tetrofosmin at the peak exercise, the early SPECT imaging was performed at 30 min (EX-30) and the delayed imaging at 180 min (EX-180). Immediately after the delayed imaging, 740 MBq of Tc-99m-tetrofosmin was injected in the resting state, and the rest SPECT imaging was performed 30 min later. Exercise-induced regional perfusion defects and/or apparent reversible left ventricular cavity dilation were identified in 26 (68.2%) of the 44 patients. When EX-30 images and EX-180 images were compared, reverse redistribution was confirmed in 36 patients (81.8%). Reverse redistribution was detected most frequently in the septal portion of the anterior wall, followed by the septal portion of the posterior wall and the septum. Exercise/rest Tc-99m-tetrofosmin myocardial imaging was a useful method for assessing myocardial perfusion abnormalities in patients with HCM. Reverse redistribution was detected very frequently on early and delayed images of exercise. We assumed that reverse redistribution may reflect a retention disorder of Tc-99m-tetrofosmin caused by some metabolic dysfunction of myocytes.     

High‐ and moderate‐intensity aerobic exercise and excess post‐exercise oxygen consumption in men with metabolic syndrome

Physical activity is central in prevention and treatment of metabolic syndrome. High‐intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate‐intensity exercise. Furthermore, it may induce larger energy expenditure at post‐exercise recovery. The aim of this study is to compare the excess post‐exercise oxygen consumption (EPOC) in three different aerobic exercise sessions in men with metabolic syndrome. Seven men (age: 56.7 ± 10.8) with metabolic syndrome participated in this crossover study. The sessions consisted of one aerobic interval (1‐AIT), four aerobic intervals (4‐AIT), and 47‐min continuous moderate exercise (CME) on separate days, with at least 48 h between each test day. Resting metabolic rate (RMR) was measured pre‐exercise and used as baseline value. EPOC was measured until baseline metabolic rate was re‐established. An increase in O₂ uptake lasting for 70.4 ± 24.8 min (4‐AIT), 35.9 ± 17.3 min (1‐AIT), and 45.6 ± 17.3 min (CME) was observed. EPOC were 2.9 ± 1.7 L O₂ (4‐AIT), 1.3 ± 1.1 L O₂ (1‐AIT), and 1.4 ± 1.1 L O₂ (CME). There were significant differences (P < 0.001) between 4‐AIT, CME, and 1‐AIT. Total EPOC was highest after 4‐AIT. These data suggest that exercise intensity has a significant positive effect on EPOC in men with metabolic syndrome.     

心脏核素显像对经皮室间隔化学消融术治疗肥厚型梗阻性心肌病的评价

目的探讨99Tcm甲氧基异丁基异腈(MIBI)心肌灌注显像和平衡法核素心室显像在经皮室间隔化学消融术(PTSMA)治疗肥厚型梗阻性心肌病的应用价值。方法8例肥厚型梗阻性心肌病患者,于PTSMA术前3～6[平均(4±1)]d和术后7～15[平均(10±3)]d分别行99TcmMIBI静息心肌灌注显像和平衡法核素心室显像。计算室间隔和左心室侧壁放射性比值及室间隔缺损范围,左心室射血分数(LVEF)、高峰充盈率(PFR)和室间隔局部EF。结果8例患者术前心肌灌注显像均显示室间隔放射性浓聚。术后心肌灌注显像示7例部分室间隔放射性缺损,其中1例伴左心室下壁放射性缺损;术后室间隔和左心室侧壁放射性比值明显低于术前(0.76±0.14比1.15±0.11,P<0.01),室间隔缺损范围占左室的(6.42±1.29)%;仅1例室间隔放射性计数无明显变化。术后PFR明显高于术前[(2.29±0.24)EDVs比(1.62±0.28)EDVs,P<0.01],室间隔局部EF明显低于术前[(34±9)%比(57±7)%,P<0.01],但LVEF无明显变化。结论心脏核素显像有助于判断PTSMA所致心肌损害和心室功能变化。     

扩张型心肌病患者双嘧达莫负荷心肌201Tl SPECT显像分析

目的 观察扩张型心肌病患者的双嘧达莫负荷心肌201Tl SPECT显像表现.方法 2008年8月至2009年12月临床符合扩张型心肌病诊断标准的住院患者30例,按体质量0.56 mg/kg给予其双嘧达莫,于4 min内静脉注射,2 min后注射201Tl,注射完后10及240 min分别进行双嘧达莫负荷心肌201Tl SPECT显像,图像经三维重建后由2位以上有经验的核医学科医师进行分析.结果 27例(90.00%)患者的双嘧达莫负荷201Tl图像(10 min)显示左心室心肌放射性分布异常.延迟(240 min)显像时所有患者均出现左室心肌放射性分布异常,其中6例患者出现"反向再分布".结论 双嘧达莫负荷心肌201Tl SPECT显像对指导扩张型心肌病的诊治具有一定的临床意义.     

MR黑血和白血技术诊断肥厚型心肌病的价值

目的：研究MR黑血和白血技术在诊断肥厚型心肌病中的价值。方法：采用心脏MR黑血和白血技术及多平面成像方式，对15例临床拟诊为肥厚型心肌病的患者进行检查。结果：MR黑白技术提供病变部位、厚度、信号、心腔形态、大小等信号。白血技术能反映心肌的运动，流出道有无狭窄及程度，二尖瓣有无返流等情况。多平面成像更全面了解病变的部位和范围，避免漏诊。MR的基本特征有室壁肥厚、心肌信号不均匀、左心室流出道狭窄、心肌运动不均匀、二尖瓣少量返流和心包积液等。结论：MR黑白和白血技术对肥厚型心肌病的诊断能提供更为准确、全面的影像学信息。     

MRI延迟强化在肥厚型心肌病中的临床意义

目的 回顾性分析肥厚型心肌病(HCM)左心室心肌肥厚MRI延迟强化与临床特征的关系.方法 收集79例HCM患者行MR检查,先常规实施心脏结构和功能检查,再进行钆对比剂延迟强化(LGE)扫描.按17节段法,分别测量心肌厚度、射血分数、左心室舒张期末容积等,并进行LGE评分.性别、胸闷等组间LGE的差异采用卡方检验,临床特征与测得数据采用Logistic回归分析,并以分析出阳性症状为参考标准评价LGE预测心脏事件的准确性,比较ROC曲线下面积.结果 79例患者共计1343节段,其中肥厚节段633个,基底段前室间隔(第2节段)肥厚节段数最多(64个),其次为第9、3和8节段,分别为58、57和57个.LGE显示受累节段433个,第2节段最多(51个),其次为第8、9和14节段,分别为39、37和36个.左心房前后直径、LGE是心房颤动的独立预测因子(HR分别为1.11和1.12,P≤0.01),ROC曲线下面积分别为0.726、0.743;LGE是非持续性室性心律失常(NSVT)的独立预测因子(HR=1.15,P≤0.01),ROC曲线下面积为0.817.结论 HCM患者心肌肥厚及LGE呈不对称性分布,LGE是HCM发生NSVT及心房颤动的独立危险因素.     

心脏MR评价肥厚型心肌病左心房功能的应用研究

目的 探讨心脏MR在肥厚型心肌病的左心房功能评估中的价值,分析肥厚型心肌病的左心房功能的变化特点.方法 回顾性分析29例肥厚型心肌病患者的心脏MR资料,获取临床常规的二腔心、三腔心以及四腔心电影序列图像,使用心脏分析软件Report-Card 4.0测量左心房的内径、容积,评价左心房的收缩功能.收集30例正常志愿者作为对照,比较肥厚型心肌病组与正常组之间的左心房内径、容量以及功能的差异.结果 29例肥厚型心肌病左心房二腔心长径、四腔心长径、三腔心前后径较对照组增大[分别为（62.55±8.19）mm和（44.35±6.34）mm,t=9.565;（70.10±12.05）mm和（53.95±6.96）mm,t=6.332;（41.37±8.99）mm和（28.89±4.36）mm,t=6.819）],左心房二腔心面积、四腔心面积、三腔心面积较对照组增大[（分别为（2698.24±749.16）mm^2和（1634.41±294.67）mm^2,t=7.298;（3077.50±863.77）mm^2和（1909.23±323.86）mm^2,t=6.925;（2622.14±720.42）mm^2和（1633.63±281.41）mm^2,t=7.269）],左心房最大容积、最小容积、左房收缩前容积较对照组增大[（分别为（116.62±49.34）ml和（60.08±13.18）ml,t =6.058;（70.38±42.22）ml和（22.06±7.90）ml,t=6.161;（96.37±44.42）ml和（38.96±12.09）ml,t=6.825）],左心房射血分数、被动射血分数、主动射血分数较较正常组减小[（分别为（41.53±11.70）％和（63.61±9.56）％,t=-7.952;（17.55±9.48）％和（50.41±15.13）％,t=-9.958;（28.94±12.54）％和（43.20±12.78）％,t=-4.324）,两组之间的差异均有统计学意义（P值均小于0.05）.结论 利用心脏MR中临床常规的二、三、四腔心电影序列,对肥厚型心肌病患者的左心房功能进行定量评估发现,肥厚型心肌病患者不仅表现为心房增大,其心房的收缩功能也明显减退.