肥厚型心肌病的治疗进展

肥厚型心肌病（HCM）是以心肌肥厚为特征的疾病，常为不对称肥厚并累及室间隔，左心室血液充盈受阻、舒张期顺应性下降为基本病态的心肌病。根据左心室流出道有无梗阻，可分为梗阻性肥厚型心肌病和非梗阻性肥厚型心肌病。梗阻型可以是主动脉瓣下或心室中部梗阻，梗阻可以隐匿（可诱发）、间歇或持续存在。非梗阻型静息或激发时均无收缩期梗阻。HCM临床主要表现为劳累时呼吸困难、心绞痛、晕厥、头晕，部分患者可无症状，     

静脉注射美托洛尔对肥厚型心肌病左心室功能的影响

目的:应用频谱多普勒超声心动图技术,定量观测肥厚型梗阻性心肌病和肥厚型非梗阻性心肌病患者经静脉注射美托洛尔前后左心室功能和左心室流出道压力阶差的变化,并观察血流动力学的变化,探讨静脉注射美托洛尔对肥厚型心肌病左心室功能的影响。方法:应用PHILIPS-SONOS7500型彩色多普勒超声诊断仪,测量用药前和用药后10分钟肥厚型梗阻性心肌病组(n=33)和肥厚型非梗阻性心肌病组(n=26)患者左心室功能各指标,并监测用药过程中的血流动力学变化。结果:肥厚型梗阻性心肌病组患者用药后较用药前左心室舒张功能明显改善,左心室流出道(LVOT)明显增宽(P<0.05),左心室流出道压力阶差(LVOTPG)明显下降(P<0.05),EF值无明显变化(P>0.05);肥厚型非梗阻性心肌病组患者用药后较用药前上述各指标无明显变化(P>0.05)。两组的心率、收缩压、舒张压用药后较用药前均明显降低(P<0.05),有显著差异。结论:静脉注射美托洛尔能够快速改善肥厚型梗阻性心肌病组患者的左心室舒张功能,改善临床症状,明显减轻左心室流出道梗阻,降低压力阶差,明显降低两组的血压、心率,影响其血流动力学;而对肥厚型非梗阻性心肌病组患者无明显作用,对两组的收缩功能均无明显影响。     

肥厚型心肌病患者血浆基质金属蛋白酶-1水平与左心室流出道梗阻关系的研究

目的探讨肥厚型心肌病(HCM)患者血浆基质金属蛋白酶-1(MMP-1)水平与左心室流出道梗阻的关系。方法纳入肥厚型心肌病患者72例,以基质金属蛋白酶-1(MMP-1)平均水平5.13 ng/ml为界将患者分为高MMP-1组(n=34)和低MMP-1组(n=38),分析两组患者性别、年龄、超声影像学等相关指标差异及与MMP-1相关的指标,同时比较梗阻性HCM与非梗阻性HCM患者的MMP-1水平差异。结果与低MMP-1组比较,高MMP-1组患者在年龄、氨基末端脑钠肽前体(NT-proBNP)、左心室流出道最大压差(LVOTPG)、左心室射血分数(LVEF)、左室后壁宽度(LVPWD)五项指标上存在统计学差异(P0.05)。NT-proBNP与MMP-1呈正相关(r=0.521,P=0.025),LVOTPG与MMP-1呈正相关(r=0.596,P=0.018),LVEF与MMP-1呈负相关(r=-0.471,P=0.031),LVPWD与MMP-1无显著相关性。梗阻性HCM患者较非梗阻性HCM患者的MMP-1水平显著升高,差异有统计学意义(P0.05)。结论 MMP-1与NT-proBNP、LVOTPG、LVEF有相关性,在肥厚型心肌病患者左心室流出道梗阻的判断中有一定的价值。     

经胸超声心动图评价高血压心脏病与左心室流出道梗阻的应用价值

目的:应用经胸超声心动图(transthoracic echocardiography,TTE),评价高血压心脏病与肥厚型心肌病(HCM)左心室流出道梗阻的二维及血流动力学特征,为临床鉴别诊断提供影像学依据。方法:左心室流出道梗阻患者31例,其中高血压性左心室流出道梗阻12例,肥厚型梗阻性心肌病19例,二维图像下测量两组患者的室间隔厚度及左心室后壁厚度,在静息状态和激发试验后测量两组患者的左心室流出道流速及最大压差,分别进行组间及组内比较。结果:室间隔厚度肥厚型心肌病组(19.6±1.8)mm明显高于高血压组(12.4±0.6)mm,差异有统计学意义(P<0.05)。左心室后壁厚度:肥厚型心肌病组(11.5±0.5)mm,高血压组(11.3±0.6)mm,两组间比较差异无统计学意义(P>0.05)。高血压组组内比较激发试验后左心室流出道流速(398.6±36.7)cm/s及压差[(68.4±12.9)mmHg,1 mmHg=0.133kPa],均高于静息状态下流速178.2±23.4)cm/s,压差(13.5±6.2)mmHg,差异有统计学意义(P<0.05)。结论:经胸超声心动图能准确评价左心室流出道梗阻的解剖结构与血流动力学特征,可准确鉴别梗阻类型及梗阻程度。     

药物负荷超声心动图检测心功能减低者存活心肌

目的评价小剂量多巴酚丁胺、硝酸异山梨酯单用及合用的二维超声心动图(2DE)检测冠心病左心室收缩功能严重减低患者存活心肌的安全性和准确性。方法对40例陈旧性心肌梗死拟接受冠状动脉血运重建术患者进行多巴酚丁胺(3、5、10μg·kg-1·min-1)、硝酸异山梨酯及两药合用的负荷2DE检测。结果硝酸异山梨酯与多巴酚丁胺(3、5μg·kg-1·min-1)合用无诱发心肌缺血,检测敏感性和准确性均较两者单用时显著提高(P值均<0·05),且副作用发生率显著降低(P<0·05)。硝酸异山梨酯+多巴酚丁胺5μg·kg-1·min-12DE的敏感性、特异性和准确性均达多巴酚丁胺10μg·kg-1·min-12DE水平。多巴酚丁胺10μg·kg-1·min-1可诱发心肌缺血。结论多巴酚丁胺5~10μg·kg-1·min-12DE检测左心室收缩功能严重减低患者存活心肌效果较好,但可诱发心肌缺血。硝酸酯与多巴酚丁胺合用能提高检测敏感性和准确性,且更安全。     

在心内三维超声指导下经皮心内膜室间隔射频消融术治疗肥厚型梗阻性心肌病

正肥厚型梗阻性心肌病(HOCM)是一类因编码肌小节或肌原纤维的基因突变引发的以室间隔或心尖部心肌非对称性肥厚为主要表现的常染色体显性遗传性疾病;其发病率约为0.2%,实际发病率可能高于这个数值;室间隔肥厚可伴或不伴二尖瓣前叶收缩期前向运动(SAM),使左心室射血受阻,从而在左心室流出道(主动脉瓣下)形成跨瓣压差,即左心室流出道压差(LVOTPG)。一般将静息或诱发时经超声多普勒测算的     

肥厚型心肌病患者小动脉弹性指数水平与左心室流出道梗阻的关系

目的：探讨肥厚型心肌病（HCM）患者小动脉弹性指数（C2）水平与左心室流出道梗阻的关系. 方法：纳入2010年1月至2013年7月间因肥厚型心肌病于我院心内科住院的患者69例,收集相关临床资料,比较C2水平与相关指标的关联性.再根据左心室流出道梗阻情况的不同,将HCM患者分为梗阻性HCM与非梗阻性HCM,比较两组患者的C2水平. 结果：N末端B型利钠肽原（NT-proBNP）、左室流出道最大压差（LVOTPG）与C2呈显著负相关,左室短轴缩短率（LVFS）与C2呈显著正相关,左室后壁宽度（LVPWD）与C2无显著相关性,超敏肌钙蛋白I（c-TNI）、左室射血分数（LVEF）、左室舒张末期内径（LVEDD）与C2呈非线性相关.梗阻性HCM患者的C2水平显著低于非梗阻性HCM患者. 结论：C2与LVOTPG密切相关,该指标可作为HCM患者左心室流出道梗阻病情进展的动态评价指标.     

肥厚型心肌病的发病机制、诊断及治疗进展

肥厚型心肌病(hypertrophic cardiomyopathy,HCM)是以无明显原因的左心室不对称性肥厚为特征,导致左心室血液充盈受阻、舒张期顺应性下降为基本病变的心肌病。根据左心室流出道有无梗阻又可分为梗阻性(hypertrophic obstructive cardiomyopa-thy,HOCM)和非梗阻性(hypertrophic non-obstructive cardiomyopathy,HNCM)2种。心尖部肥厚型心肌病(apical hypertrophic cardiomyopathy,AHCM)属于肥厚型心肌病中的特殊类型,其肥厚的心肌主要位于前侧壁心尖部,而室间隔基底部却多无肥厚,常不伴有左心室流出道梗阻和压力阶差。目前认为HCM     

腺苷与多巴酚丁胺负荷超声检测兔冬眠心肌的冠脉造影比较

目的比较腺苷负荷超声心动图(ASE)与多巴酚丁胺负荷超声心动图(DSE)结合二维斑点追踪成像技术(STE)在识别冬眠心肌中的应用价值。方法对照组10只家兔开胸不结扎左前降支,模型组26只家兔开胸不全结扎左前降支。1个月后行药物负荷试验,测量节段心肌的收缩期峰值径向应变(PRS),与冠脉造影结果比较。结果正常组心肌PRS随多巴酚丁胺剂量的增加而增加(P<0.05),冬眠心肌在静息状态、多巴酚丁胺5μg.kg-1.min-1时PRS随着剂量的增加而增大;10μg.kg-1.min-1时PRS没有明显增大,20μg.kg-1.min-1时反而明显减小。正常组心肌各节段的PRS随腺苷剂量的增加而逐渐增大,但各级负荷之间的差异无统计学意义。冬眠心肌在静息状态、腺苷80μg.kg-1.min-1时PRS随着剂量的增加而增大;100μg.kg-1.min-1时反而明显减小。DSE结合STE检测冬眠心肌的敏感性为90.9%,特异性为85.7%。ASE结合STE检测冬眠心肌的敏感性为87.8%,特异性为87.8%。结论 ASE及DSE结合STE均能有效识别冬眠心肌。二者结果比较,ASE的特异性高于DSE,但敏感性不如DSE高。     

运动负荷超声在评估肥厚型心肌病梗阻类型中的应用

目的 评估肥厚型心肌病(HCM)患者静息和运动中左室流出道梗阻的情况.方法 连续入选的60例静息左室流出道压差(LVOTG) ＜50 mm Hg(1 mm Hg=0.133 kPa)的HCM患者,超声测量静息LVOTG和运动峰值LVOTG.51例静息LVOTG＜ 30 mm Hg的患者中,26例患者运动峰值LVOTG≥30 mm Hg为潜在梗阻,25例运动峰值LVOTG＜ 30 mm Hg为非梗阻.9例静息LVOTG30 ～49 mm Hg为静息梗阻.分析不同类型梗阻的形态学特征.结果 潜在梗阻与非梗阻患者相比,二尖瓣前叶收缩期前向运动(SAM)征(73.1％比8.0％)、流出道狭窄(46.2％比4.0％)更常见、二尖瓣反流程度更重、静息LVOTG[(16.9±7.2) mm Hg比(7.1 ±4.3)mm Hg]更高,室间隔肥厚部位分布差异有统计学意义(P值均＜0.05).多因素logistic回归分析,SAM征(OR 6.431,95％ CI2.323 ～291.112,P=0.002)和室间隔肥厚部位(OR0.011,95％ CI0.001 ～0.179,P=0.008)为发生潜在梗阻的独立预测因素.结论 约半数静息无梗阻的HCM患者存在潜在梗阻.SAM征和室间隔肥厚部位有助于潜在梗阻的识别.     

负荷超声心动图与负荷单光子发射计算机断层显像评价冠脉介入术后再狭窄（英文）

目的：探讨运用多巴酚丁胺负荷超声心动图（DSE）和硝酸甘油负荷单光子发射计算机断层灌注显像（SPECT）来评价经皮冠状动脉介入（PCI）术后再狭窄的价值。方法：39例PCI术后的患者,在冠状动脉造影前1周内接受DSE和SPECT检查,多巴酚丁胺剂量递增方案为5μg.kg-1.min-1,10μg.kg-1.min-1,20μg.kg-1.min-1,30μg.kg-1.min-1,40μg.kg-1.min-1五个级别,每级负荷维持3min。按照冠脉造影的结果确定DSE,SPECT的敏感性、特异性和准确度,分析比较DSE,SPECT和冠脉造影检查的结果。结果：与冠脉造影相比,SPECT、DSE检查评价PCI术后再狭窄的敏感性（83.3%比75.0%）,准确性（71.8%比87.2%）无显著差异P〉0.05,但与SPECT相比,DSE检查的特异性较高（66.7%比92.6%）,P〈0.05。结论：多巴酚丁胺负荷超声心动图评价经皮冠状动脉介入术后再狭窄准确,且特异性好于SPECT。     

比较小剂量多巴酚丁胺负荷磁共振评价陈旧性心肌梗死和心肌活性的联系

目的:比较小剂量多巴酚丁胺负荷磁共振(MRI)和延迟强化MRI评价陈旧性心肌梗死和心肌活性的价值。方法:25例陈旧性心肌梗死患者于血运重建前行静息及小剂量多巴酚丁胺负荷(5～10μg.kg-1.min-1)心脏电影MRI和延迟强化心脏MRI,小剂量多巴酚丁胺负荷MRI存活心肌的定义为:≥2个相邻的静息期无运动及反向运动的节段,负荷后节段心肌收缩≥2 mm;延迟强化透壁程度分为5个等级评分,分别为无强化(0分),0～25%(1分),25%～50%(2分),50%～75%(3分),75%～100%(4分),节段心肌评分≤2为预测心功能可恢复。结果:延迟强化透壁程度≤50%的心肌节段(评分0～2),89%多巴酚丁胺负荷阳性;延迟强化透壁程度≥75%的心肌节段(评分4),21%多巴酚丁胺负荷阳性(P0.05)。延迟强化透壁程度在50%～75%(评分3)之间时,54%多巴酚丁胺负荷阳性,46%多巴酚丁胺负荷阴性。结论:当延迟强化为心内膜下强化和透壁强化时,与多巴酚丁胺负荷一致性好。当延迟强化透壁程度在50%～75%(评分3)之间时,需要进一步进行多巴酚丁胺负荷以更好地预测心肌活性。     

硝酸酯、小剂量多巴酚丁胺及其合用超声心动图试验识别急性心肌梗死存活心肌的对比研究

目的对比硝酸酯、小剂量多巴酚丁胺(Dob)及其合用二维超声心动图(2DE)试验识别急性心肌梗死(AMI)存活心肌的准确性和安全性。方法AMI患者31例,于发病后7～14(10±3)d行硝酸酯、小剂量Dob及其合用2DE试验,后行冠状动脉血运重建(CRV)术成功,术后6个月左右(167±18)d复查2DE。用16节段半定量分析法对左室各节段收缩运动和增厚情况给予分级记分。将2DE试验所检的存活心肌与CRV术后其收缩功能改善的实际对比,评价识别AMI存活心肌的准确性和安全性。结果31例AMI患者共有221个异常节段。与硝酸酯和Dob3μg单用时相比,两者合用2DE试验对AMI区存活心肌节段的检出率均显著提高（50.2%对37.6%和40.7%,P均<0.05）,识别敏感性和准确性也均显著提高（77.6%对56.8%和61.6%,81.0%对70.1%和72.4%,P<0.05～0.01）;而硝酸酯合用Dob5μg2DE试验对存活心肌的检出率、识别敏感性和准确性均已达Dob10μg单用时的水平（55.7%对55.8%,87.2%对89.5%和86.4%对87.9%,P均>0.05）,而又无Dob10μg诱发心肌缺血的副作用。结论硝酸酯与小剂量(3、5μg     

Dobutamine stress echocardiography in hypertrophic cardiomyopathy

AIMS: Myocardial ischemia in the absence of coronary artery disease is common in patients with hypertrophic cardiomyopathy (HCM). Dobutamine stress echocardiography (DSE) induces left ventricular (LV) new wall motion abnormalities (NWMA) in some patients with HCM. We evaluated the effects of dobutamine on LV performance and hemodynamics in HCM. METHODS AND RESULTS: Eighteen patients with non-obstructive HCM underwent DSE. Dobutamine was administered at dosages of 5, 10, 20, 30 and 40 microg/kg/min with increments at intervals of 3 min. Seven patients developed NWMA, whereas the other 11 did not. During DSE, heart rate increased significantly more in NWMA patients,whereas LV outflow tract gradient (OTG) increased significantly and similarly in both groups. At peak dobutamine dose, NWMA patients had a significant increase in LV end-systolic diameter and volume and a significant decrease in LV fractional shortening and ejection fraction. Posterior wall thickening increased significantly, whereas septal thickening did not increase throughout DSE in both groups. CONCLUSIONS: In a subgroup of patients with HCM, DSE induces NWMA, associated with a greater increase in heart rate, irrespective of LVOTG. NWMA induce a depression of global LV systolic performance. The septum shows no contractile reserve, regardless of NWMA. These phenomena may be the result of induction of ischemia and/or impaired LV systolic function due to fast heart rate.     

Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy

OBJECTIVES: We sought to characterize stress-induced left ventricular systolic dysfunction in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: Myocardial ischemia and diastolic dysfunction occur in patients with HCM. We hypothesized that, in the setting of transient myocardial ischemia, left ventricular systolic dysfunction occurs during exercise and dobutamine stress. METHODS: We studied 39 patients with HCM but without obstructive symptoms at rest or coronary artery disease. A continuous ventricular function monitor equipped with cadmium telluride detectors (VEST) was used to evaluate left ventricular function during supine bicycle ergometer exercise. Dobutamine stress echocardiography (DSE) was also performed. The left ventricular ejection fraction (LVEF) and regional wall motion were determined from echocardiographic images. RESULTS: Changes in the LVEF correlated between exercise and dobutamine stress (r = 0.643, p < 0.0001). The LVEF decreased more than 5% at peak exercise in 17 of patients (group II), while the other patients had normal responses (group I). New regional wall motion abnormalities during dobutamine infusion were detected in 18 of 110 (16.4%) segments in group I and 42 of 85 (49.4%) segments in group II. Decreased or unchanged regional wall motion occurred more frequently in hypertrophied segments than in nonhypertrophied segments (p < 0.0001). There were significant inverse correlations between the LVEF responses during both stresses and the number of abnormal segments noted during dobutamine stress in all patients (VEST: p < 0.005; DSE: p < 0.0005). Signs of left ventricular obstruction were observed in 11 of 39 patients during DSE. However, there was no significant correlation between the LVEF response and the dobutamine-induced left ventricular pressure gradient. CONCLUSIONS: Exercise-induced systolic dysfunction occurred in 50% of patients with HCM. In these patients, regional wall motion abnormalities were present in hypertrophied segments.     

心尖肥厚型心肌病与典型肥厚型心肌病的临床特点比较

目的 通过与典型的肥厚型心肌病(HCM)比较,探讨中国汉族人心尖肥厚型心肌病(AHCM)的临床特征及其诊治方法.方法 回顾性收集160例HCM住院患者的临床资料,分成3组进行比较.AHCM组:AHCM 41例.典型HCM患者(室间隔以及左心室壁肥厚),根据是否存在流出道梗阻分成2组,即非梗阻性肥厚型心肌病(NOHCM)组,52例,左心室流出道压差＜30 mm Hg(1 mm Hg=0.133 kPa);梗阻性肥厚型心肌病(OHCM)组,67例,左心室流出道压差≥30mm Hg.比较3组患者的临床症状、诊治方法以及血浆生物标记物水平.结果 (1)AHCM组患者的发病年龄较OHCM组晚[(49.9±13.6)岁比(41.4±14.6)岁,P＜0.01],无猝死家族史,较少出现劳力性呼吸困难,血浆血N末端B型利钠肽原(NT-pro BNP)水平较OHCM组低(P＜0.01).血浆心肌酶中肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)、肌钙蛋白I(TnI)和肌红蛋白(MYO)的水平在3组间差异均无统计学意义.(2)31例AHCM患者因冠心病收治入院,经检查后,18例(18/41,43.9%)排除了冠心病.(3)AHCM组、NOHCM组和OHCM组心电图上深尖倒置T波(GNT)出现的频率分别为43.9%、13.5%和4.4%(P＜0.01),且AHCM组多伴有左心室高电压.(4)心脏核磁共振诊断AHCM明显优于心脏超声,与诊断典型HCM相比更有优势.结论 AHCM与典型OHCM的临床特点比较差异有统计学意义,而与典型的NOHCM比较差异无统计学意义.心脏核磁共振检查阳性及心电图胸导联上典型的GNT可为确诊AHCM提供依据.

Abstract：

Objective To evaluate the clinical features in Chinese patients with apical hypertrophic cardiomyopathy (AHCM) and typical hypertrophic cardiomyopathy (HCM). Methods This retrospective analysis included 160 patients hospitalized in Fuwai hospital. Patients were divided into three groups: apical hypertrophic cardiomyopathy ( AHCM, n = 41 ) group, non-obstructive typical hypertrophic cardiomyopathy group[NOHCM, LVOT ＜30 mm Hg(1 mm Hg =0. 133 kPa) at rest, n =52] and obstructive typical hypertrophic cardiomyopathy (OHCM, LVOT ≥ 30 mm Hg at rest, n = 67). Clinical features, diagnosis,therapy, and plasma levels of biomarkers of these three groups were analyzed. Results ( 1 ) The age at disease onset was older in AHCM group than in OHCM group [(49. 9 + 13. 6) years vs. (41.4± 14. 6)years, P ＜ 0. 01]. Exertional dyspnea appered more often in HCM patients than in AHCM patients, NT-proBNP level was significantly lower in AHCM patients than in OHCM patients (P =0. 001 ). Plasma CK-MB, LDH, TnI and MYO levels were similar among the three groups. (2) Thirty-three AHCM patients were first hospitalized for suspected coronary heart disease (CHD) and CHD was excluded in 18 cases (43.9%).(3) The frequency of giant negative T waves (depth≥10 mm) on ECG was 43.9%, 13.5% and 4.4%(P ＜ 0. 01 ) in AHCM, NOHCM and OHCM respectively. Half of AHCM patients showed left ventricular high voltage on ECG. (4) Cardiac magnetic resonance imaging is superior to echocardiography on correctly diagnosing AHCM. Conclusion AHCM patients differ from typical OHCM patients in clinical characteristics. There were significant differences on echocardiography and electrocardiography features among three groups. Cardiac magnetic resonance imaging and giant negative T waves on ECG are helpful for the diagnosis of AHCM.     

不同动脉压水平对老年感染性休克患者血流动力学组织灌注和代谢的影响

目的 观察应用去甲肾上腺素联合多巴酚丁胺(NE+Dobu)在小同平均动脉压(MAP)水平对老年感染件休克患者血流动力学、组织灌注和代谢的影响. 方法 感染性休克患者18例,充分液体复苏后为基础状态,应用NE+Dobu并随机调节剂量,使MAP分别维持在65、75、85mm Hg 3种水平状态,持续4 h,观察不同MAP水平的血流动力学、氧合指标、血乳酸、肾功能和胃黏膜二氧化碳分压变化. 结果 当MAP达75 mm Hg和85 mm Hg时,心脏指数(4.7±0.6和5.1±0.7)、体循环阻力指数(1162±278和1276±319)、氧输送[(697±53)ml·min-1·m-2和(711±68)ml·min-1·m-2]、氧摄取率[(0.28±0.02)%和(0.27±0.02)%],均较MAP为65 mm Hg时[4.0±0.6、1011±225、(634±70)ml·min-1·m-2、(0.25±0.02)%]明显增加(P<0.05);尿量分别为(98±43)ml/h和(91±54)ml/h,较65 mm Hg时(74±49)ml/h有明显增加,但仅MAP75 mmHg时,差异有统计学意义(P<0.05). 结论 老年感染性休克患者充分液体复苏后,应用NE+Dobu提高MAP达75 mm Hg时,可改善全身血流动力学和肾功能,对于老年感染性休克患者可能需要适当提高MAP.     

Dynamic intraventricular obstruction during dobutamine stress echocardiography. A new observation.

BACKGROUND. The implications of hypotension occurring during dobutamine stress echocardiography have not been elucidated. We observed in some patients that hyperdynamic left ventricular function developed during dobutamine stress echocardiography and hypothesized that intracavitary obstruction was occurring and might account for hypotension in some patients. METHODS AND RESULTS. Fifty-seven consecutive patients undergoing dobutamine stress echocardiography underwent pulsed-wave and continuous-wave Doppler examination of the left ventricular cavity at rest and at peak dobutamine infusion. The development of an intraventricular gradient with dobutamine stress was defined as a late-peaking left ventricular Doppler velocity profile that exceeded basal velocity by at least 1 m/sec. During dobutamine stress testing, left ventricular outflow velocity or intracavitary velocity increased in all patients. Obstruction occurred in 12 patients (21%, group 1). Group 2 was the remaining 45 patients. Peak velocities in group 1 ranged from 2.0 to 5.0 m/sec (mean, 3.5 m/sec), and the mean increase from velocity at rest was 2.3 m/sec. The mean change in systolic blood pressure was significantly lower in patients in group 1 (-15 versus 4 mm Hg, p = 0.02). When the 18 patients with an ischemic response to stress testing (evidenced by new or worsening wall motion abnormalities) were excluded from analysis, systolic blood pressure response was still significantly different for the two groups (-19 versus 2 mm Hg, p = 0.03). CONCLUSIONS. Dynamic left ventricular obstruction is a new observation; it may develop frequently in patients undergoing dobutamine stress echocardiography. Obstruction rather than ischemia may explain a decrease in blood pressure during dobutamine stress echocardiography.     

Latent Obstruction and Left Atrial Size Are Predictors of Clinical Deterioration Leading to Septal Reduction in Hypertrophic Cardiomyopathy

BackgroundExercise echocardiography is a reliable tool to assess left ventricular (LV) dynamic obstruction in hypertrophic cardiomyopathy (HCM). The aim of this study was to determine the role of exercise echocardiography in the evaluation of latent obstruction and in predicting clinical deterioration in HCM patients.Methods and ResultsWe considered 283 HCM patients studied with exercise echocardiography. The end point was clinical deterioration leading to septal reduction (myectomy or alcohol septal ablation). LV latent obstruction was present at enrollment in 67 patients (24%). During a mean follow-up of 42 ± 31 months, 42 patients had clinical deterioration leading to septal reduction therapy: in 12/67 (22%) patients with a latent obstruction at enrollment, in 28/84 (33%) patients with obstruction at rest, and in 2/132 (1.5%) with obstruction neither at rest or during stress. Multivariate analysis identified the following variables as independently associated with the end point: LV gradient >30 mm Hg at rest (hazard ratio [HR] 2.56, 95% CI 1.27–5.14; P = .009), LV gradient >30 mm Hg during stress (HR 4.96, 95% CI 1.81–13.61; P = .002), and indexed left atrial volume (LAVi ) >40 mL/m² (HR 2.86, 95% CI 1.47–5.55; P = .002). In patients with a latent obstruction, the strongest independent predictor of outcome was LAVi >40 mL/m² (HR 3.75, 95% CI 1.12–12.51; P = .032).ConclusionsAssessment of LV gradient during stress with exercise echocardiography is an important tool for the evaluation of latent obstruction in HCM and may have a role in risk stratification of these patients.