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.     

Transesophageal Doppler echocardiography in obstructive hypertrophic cardiomyopathy: clarification of pathophysiology and importance in intraoperative decision making.

To better understand the pathophysiology of obstruction of left ventricular outflow in hypertrophic cardiomyopathy and to determine the value of intraoperative transesophageal Doppler echocardiography in decision making, 32 consecutive patients undergoing ventriculomyectomy were assessed. The mean preoperative left ventricular outflow gradient was 83 +/- 39 mm Hg and the mean basal septal width was 24 +/- 6 mm. Compared with transesophageal findings in 10 normal control subjects, the mitral leaflets were longer and the coaptation point was abnormal in the patients with obstructive hypertrophic cardiomyopathy (anterior and posterior leaflet lengths in the patients were 31 +/- 4 vs. 22 +/- 3 mm in the control group [p less than 0.00001] and 20 +/- 2 vs. 15 +/- 3 mm in the control group [p less than 0.00001]). The coaptation point in the patient group was in the body of the leaflets at a mean of 9 +/- 2 mm from the anterior leaflet tip, whereas it was at or within 3 mm of the leaflet tip in the normal group. During early systole, the distal third to half of the anterior mitral leaflet angled sharply anteriorly and superiorly (systolic anterior motion), resulting in leaflet-septal contact and incomplete mitral leaflet coaptation in mid-systole. This caused the formation of a funnel, composed of the distal parts of both leaflets, that allowed a jet of posteriorly directed mitral regurgitation to occur in mid- and late systole. The sequence of events in systole was eject/obstruct/leak. Transesophageal echocardiography was also helpful in planning the extent of the resection, assessing the immediate result and excluding important complications. In successful cases, the post-myectomy study showed 1) a dramatic thinning of the septum, with widening of the left ventricular outflow tract to a width similar to that in the normal subjects, 2) resolution of systolic anterior motion and the left ventricular outflow tract color mosaic, and marked reduction or abolition of mitral regurgitation despite persistence of abnormal mitral leaflet length and an abnormal mitral leaflet coaptation point. The routine use of transesophageal echocardiography in patients undergoing surgical myectomy for the treatment of obstructive hypertrophic cardiomyopathy is recommended.     

Impact of intraoperative echocardiography on surgical management of congenital heart disease

Intraoperative echocardiography was performed by epicardial, 2-dimensional, low- and high-pulsed repetition frequency, continuous-wave Doppler and color flow mapping in 50 patients. Forty studies were performed before and 44 studies after cardiopulmonary bypass. Studies before cardiopulmonary bypass agreed with preoperative evaluation. After cardiopulmonary bypass, studies revealed that 11 of 25 patients who underwent repair of ventricular septal defects had residual ventricular septal defects, and 1 of 25 patients who underwent atrial septal repair had 1 residual atrial communication. One patient with a "Swiss cheese" ventricular septum underwent repeat cardiopulmonary bypass to close residual ventricular septal defects. The patient with a residual atrial communication required immediate reoperation because of a right to left shunt after a modified Fontan procedure. Eight of 10 remaining residual ventricular septal defects spontaneously closed 1 to 41 days after operation. Assessment of postcardiopulmonary bypass and postoperative valvular regurgitation in 21 valves revealed good correlation (p less than 0.01). However, 1 patient required reoperation for mitral valve replacement on the sixth postoperative day. The correlation was fair between postcardiopulmonary bypass and postoperative residual stenotic pressure gradients in 12 surgically repaired stenotic lesions. This study shows that little additional information is added to a comprehensive preoperative evaluation by precardiopulmonary bypass intraoperative echocardiography. Postcardiopulmonary bypass intraoperative echocardiography is useful in identifying residual shunts. Assessment of stenotic gradients and valvular regurgitation must be interpreted in light of a changing hemodynamic state.     

多巴酚丁胺在肥厚型心肌病激发试验的应用

目的 评价多巴酚丁胺激发试验在肥厚型心肌病激发试验中的安全性及有效性,比较潜在型肥厚型梗阻与静息型肥厚型梗阻性心肌病的临床特点. 方法 对22例确诊肥厚型心肌病患者(左心室流出道压力阶差正常或轻度增加)进行多巴酚丁胺激发试验,以5 μg·min-1·kg-1为起始剂量静脉泵人多巴酚丁胺,每隔5 min增加5 μg·min-1·kg-1,最大剂量20 μg·min-1·kg-1.每一次剂量泵入2 min后进行超声心动图检查,并对其临床特点与57例静息型肥厚型梗阻性心肌病患者进行比较. 结果 入选22例患者激发状态时左心室流出道流速峰值为(5.39±1.60)m/s,左心室流出道压力阶差(LVOTPG)峰值为(125.7±62.4)mm Hg(1 mm Hg=0.133 kPa);达到峰值时多巴酚丁胺给药平均速率为(13.9±6.85)μg·min-1·kg-1.16例(72.7%)患者达到阳性标准;6例(27.3%)患者虽达到阴性标准,但LVOTPG也有显著升高.潜在型梗阻患者的年龄、性别、各房室腔内径、左心室射血分数、室间隔厚度、LVOTPG等与静息型梗阻患者比较,差异均无统计学意义,但二尖瓣前向运动(SAM)现象发生率较低(62.5%比100%),Maron Ⅱ型较多[50.0%(8/16)比29.8(17/57)]. 结论 在肥厚型心肌病激发试验中,小剂量多巴酚丁胺负荷超声是一种较为安全和敏感性高的方法.潜在型较静息型肥厚型梗阻性心肌病患者的SAM现象发生率低,Maron Ⅱ型占优势.     

Contrast-enhanced echocardiography for the diagnosis of apical hypertrophic cardiomyopathy

The echocardiographic diagnosis of apical hypertrophic cardiomyopathy can be difficult in patients with poor acoustic windows. However, contrast-enhanced echocardiography can provide better images in these patients and lead to the correct diagnosis. We present a patient with apical hypertrophic cardiomyopathy who was diagnosed using contrast-enhanced echocardiography. The use of contrast-enhanced echocardiography for the diagnosis of apical hypertrophic cardiomyopathy in patients with poor acoustic windows is discussed and the experience in the literature reviewed.     

Current management of hypertrophic cardiomyopathy

Opinion statement  Hypertrophic cardiomyopathy is a heterogeneous clinical syndrome with a wide spectrum of pathophysiologic consequences. Most cases are inherited and caused by sarcomeric protein gene mutations, although phenocopies are often encountered. Genomic research and family studies have improved our recognition of the disease and understanding of its natural history; however, tenuous links exist between genotype and phenotype and thus far have done little to alter clinical management. Surgery and, more recently, implantable cardiac defibrillators have had an impact on sudden cardiac death rates, with improved short-and medium-term survival. Therefore, managing heart failure has become increasingly challenging. Although heart failure due to fibrosis and a progressive loss of contractile function is common, treatment remains largely empiric. Case series and animal studies suggest that biventricular pacing and renin-angiotensin-aldosterone system modifiers may be useful in some patients, but there is a need for large prospective randomized controlled trials to study these and other treatments. Risk stratification and eligibility for sports participation remain hot topics, but one of the greatest challenges is the management of a growing cohort of asymptomatic gene carriers identified during family screening. Ultimately, major advances in treatment and disease prevention will come from a better understanding of the genomic, proteomic, and metabolomic profiles of individual patients.     

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.     

An evaluation of two-dimensional echocardiography in the diagnosis of hypertrophic cardiomyopathy

Various anatomical and functional features of hypertrophic cardiomyopathy are analyzed in view of the data provided by two-dimensional echocardiography. Measurement of septal thickness is crucial, and is best done by a combination of M-Mode and 2-D echo. Two types of systolic anterior movement of the mitral valve (SAM) are observed and are related to the degree of subvalvular gradient. The specificity of these patterns of SAM is analyzed. The functional anatomy of the mitral valve in relation to the presence and degree of mitral regurgitation shows that although the presence and type of SAM are important, there are other causes of mitral regurgitation in hypertrophic cardiomyopathy unrelated to SAM. We emphasize the fact the 2-D echo cannot "diagnose" hypertrophic cardiomyopathy except when cardiac hypertrophy plus SAM involving the body of the mitral valve is seen; in the remaining cases, 2-D echo confirms/suggests the clinical diagnosis.     

Intraoperative evaluation and surgical planning in the hypertrophic cardiomyopathy

A male, 45 year old patient, with diagnosis of septum hypertrophic cardiomyopathy, having undergone a cardiofibrilator implant in the past. Despite the optimized clinical treatment, he evolved to a progressive clinical deterioration that led to invasive treatment. However, there was not an important gradient in the exit pathway of the left ventricle (EPLV) at the echocardiogram in rest and the challenging test with dobutamine was non conclusive because it did not reach the preconized cardiac frequency. The intraoperative evaluation with a transesophageal echocardiogram using isoproterenol was fundamental for the diagnosis of the EPLV obstruction. The septum myectomy was performed successfully and the patient presented good post-operative evolution.     

Evaluation of hypertrophic obstructive cardiomyopathy by exercise stress echocardiography. New methodology.

Exercise echocardiography with image acquisition during treadmill exercise is the most common form of stress testing used in our department. The usual evaluation of patients with hypertrophic obstructive cardiomyopathy consists of serial echocardiographic studies at rest. The purpose of this study was to evaluate intraventricular gradients during exercise echocardiography in patients with a diagnosis of hypertrophic obstructive cardiomyopathy. We studied 13 patients, 8 male, mean age 56 +/- 9 years Intraventricular gradients were measured using continuous wave Doppler; two evaluations were performed at rest: one in left lateral decubitus and the other in orthostatic position after one minute in this position. The patients then underwent a treadmill exercise test using the modified Bruce protocol, during which intraventricular gradients were measured at peak exercise. Finally, a further measurement was taken in the first 90 seconds of the recovery period in left lateral decubitus. The intraventricular gradient in left lateral decubitus was 54 +/- 29 mmHg; in orthostatic position 69 +/- 30 mmHg (p < 0.001 versus gradient in left lateral decubitus); at peak exercise 109 +/- 47 mmHg (p < 0.001 versus gradient in orthostatic position); and during recovery in left lateral decubitus 78 +/- 33 mmHg (p < 0.001 versus gradient at peak exercise in orthostatic position). We conclude that intraventricular gradients increase significantly in orthostatic position and increase considerably during treadmill exercise testing. The gradients measured in the recovery period do not reflect what happens during effort or therefore during these patients' daily activities. This type of evaluation can help us to better understand the pathophysiology of patients with a diagnosis of hypertrophic obstructive cardiomyopathy and to optimize treatment.     

Doppler echocardiography in familial hypertrophic cardiomyopathy: the French Cooperative Study

Familial hypertrophic cardiomyopathy (HCM) has been poorly studied, although it may represent 50% of all HCM. We studied 346 subjects belonging to 20 unrelated families. Patients were considered affected in view of left ventricular (LV) wall thickness. One hundred twenty-seven adults were considered affected, id est. had a left ventricular wall thickness (LVWT) > 13 mm, whereas 123 had a LVWT > 15 mm, suggesting that the cut-off value is usually not critical. Within affected patients, 95% had an asymmetrical HCM (interventricular septum/left posterior wall thickness > 1.3 mm), whereas 84% had a ratio > 1.5. Distribution of the affected patients according with Maron's classification are in keeping with published studies about sporadic forms. Doppler derived isovolumetric relaxation time was prolonged in HCM (105 +/- 23 vs 88 +/- 16 msec, P < 0.001), and the ratio peak velocity of A wave over peak velocity of E wave was significantly lower in affected individuals (0.99 +/- 0.56 vs 0.83 +/- 0.46, P < 0.05). None of the 24 children studied (10 +/- 3 years) were considered affected according to echocardiographic criteria. CONCLUSION: Echocardiography is the obligatory first step during genetic study for recognizing familial HCM. It allows classification in adults but not in children. Doppler estimate of diastolic function may be helpful in the future to recognize genetically affected subjects with normal or subnormal echocardiographic examination.     

Diagnosis of apical hypertrophic cardiomyopathy using contrast echocardiography]

Apical hypertrophic cardiomyopathy is a disease with clear electrocardiographic and echocardiographic characteristics. However, poor visualization of apical endocardial border is a limiting factor to diagnose apical hypertrophic cardiomyopathy by echocardiography. We present a case report of a patient with a characteristic electrocardiogram but poor apical endocardial border delineation. A contrast-enhanced echocardiography was performed to confirm the diagnosis of apical hypertrophic cardiomyopathy. We discuss the role of echocardiographic image enhancement with contrast to diagnose apical hypertrophic cardiomyopathy.     

超声心动图检查调查8080例成人肥厚型心肌病患病率

目的 调查8080例成年人肥厚型心肌病的患病率。方法 从2001年10月至2002年2月,我们采用整群分层随机抽样的方法对国内9市(区)8080例正常人群进行了调查,调查对象为18~74岁的成年人,男性4064例,女性4016例。调查采用调查表的方式,每个调查对象均行超声心动图、心电图、体格检查。结果 共检查出13例肥厚型心肌病的患者,其中男性9例,女性4例,均为非对称性肥厚。肥厚型心肌病患病粗率为161／100 000,年龄与性别标化后的患病率约为80／100000。结论 肥厚型心肌病并不是一种罕见的心脏疾病。     

Echocardiography evaluation of the surgical result in hypertrophic obstructive cardiomyopathy

Despite the small cohort of patients with HOCM could be shown that the routine application of the conventional and colour Doppler echocardiography after myectomy is indicated and reasonable. The modern echocardiography is able to assess with high individual reliability the therapeutic aim of myectomy--drastic reduction of the intracavitary pressure gradient. Significant changes were also the results in the systolic acceleration time (TPVS/LVET standardized on the LVET and the diastolic measuring parameters VmaxE, ATE and TVIE/TVIA), the importance of which is partly still fully open.     

Role of prenatal echocardiography in the study of hypertrophic cardiomyopathy in the fetus

The increased incidence of hypertrophic cardiomyopathy in children of diabetic mothers has already been demonstrated, but its prenatal diagnosis has not yet been extensively studied. The purpose of this prospective study was to evaluate the frequency, severity, and echocardiographic features of fetal hypertrophic cardiomyopathy in a population with several indications for prenatal echocardiography. From March 1987 to April 1991, 283 fetuses were submitted to comprehensive prenatal echocardiography, including M-mode measurements, cross-sectional imaging, Doppler studies, and color flow mapping. One hundred seventy-six were pregnancies complicated by previous or gestational diabetes. The diagnosis of disproportionate septal hypertrophy was made in 39 fetuses (mean septal thickness 7.12 +/- 1.6 mm), at a mean gestational age of 32 weeks. Diabetes mellitus was present in 36 of these pregnancies (92.3%). In four cases, nonimmune hydrops was detected. A systolic anterior motion of the mitral valve was present in three fetuses, but only one showed a gradient across the left ventricular outflow tract. Postnatal echocardiographic examination in 27 babies did not show false positivity. In ten cases, spontaneous regression of the septal hypertrophy was shown. There were three neonatal deaths, unrelated to the myocardial disease. We concluded that transient hypertrophic cardiomyopathy is a frequent entity, especially when associated with diabetes during gestation, being a potential cause for nonimmune hydrops. Fetal echocardiography is the method of choice for its prenatal diagnosis and should always be indicated in diabetic mothers.     

Contrast echocardiography in segmental analysis and intraventricular gradient quantification in hypertrophic cardiomyopathy.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is a hereditary disorder characterized by ventricular hypertrophy, diastolic dysfunction and hyperdynamic left ventricular systolic function. This excessive contraction is sometimes associated with significant intraventricular pressure gradients. These gradients are dynamic and therefore vary at different times. Echocardiography can identify and quantify the functional and morphologic changes characteristic of the disease. Ultrasound contrast agents (UCAs) are indicated in patients with poor transthoracic image quality, enabling better visualization of the endocardial border. These agents also strengthen the Doppler signal, which enables better quantification of the transvalvular and intraventricular gradients. In HCM, definition of the endocardial/blood interface and visualization of the myocardial structure, as well as quantification of intraventricular gradients, are fundamental to the study of the pathology. OBJECTIVES: The objective of this study was to evaluate the clinical utility of new UCAs in morphologic study (segmental analysis) and quantification of maximum intraventricular gradients (IVG Max) in HCM, as well as the feasibility and interest of determining mean gradients (IVG Med) in HCM. METHODS: Thirty-four patients with clinical and echocardiographic diagnosis of HCM were studied. Baseline IVG was considered significant when over 30 mmHg. Left ventricular morphology and IVG quantification were assessed before (study A) and after (study B) UCA injection. Maximum (Max) and mean (Med) values of delta IVG were calculated. Endocardial border definition of ventricular segments was analyzed in studies A and B and the percentage of ventricular segments that were completely visualized throughout the cardiac cycle was established. RESULTS: The mean values of delta IVG Max for studies A and B were 51 +/- 31 mmHg and 61 +/- 32 mmHg, p = NS. The mean values of delta IVG Med were 26 +/- 16 mmHg in study A and 31 +/- 17 mmHg in study B, p = NS. The correlation between delta IVG Max and Med in study A was r2 = 0.74, p < 0.01, while in study B it rose to a value of r2 = 0.82, p < 0.01. Segmental analysis: In all segments studied the visualization percentage was higher after UCA injection, with a statistically significant difference in all lateral and anterior wall segments. DISCUSSION AND CONCLUSIONS: HCM is usually evaluated in a non-invasive way by echocardiography. There are no references to systematic use of UCAs in HCM patients. The value of determining the maximum gradient in HCM is generally accepted, but the importance of the mean gradient is not known. In this work, UCAs improved the Doppler signal without distorting values. In HCM, values measured using UCAs have a better correlation, with a smaller discrepancy between Max and Med gradients. This study suggests that mean gradient determination enables better characterization of the dynamic variability of the gradients because there is a correlation between Max and Med gradients. The real importance of mean gradients is not yet established, so further studies are necessary. In conclusion. UCAs are very useful in morphological assessment. The interest of UCAs in determining intraventricular gradients and the value of mean gradients in HCM are not clearly demonstrated in this study.     

Mitral regurgitation in hypertrophic cardiomyopathy. Non-invasive study by two dimensional Doppler echocardiography

Mitral regurgitation and its haemodynamic features were investigated non-invasively in cases of hypertrophic cardiomyopathy by means of two dimensional Doppler echocardiography. There were 28 patients, 14 of whom showed systolic anterior motion (SAM) of the mitral echo; the other 14 did not. The following results were obtained. (1) Mitral regurgitation was detected by the Doppler technique in all cases with systolic anterior motion of the mitral echo and in half of those without it. (2) Doppler signals of mitral regurgitation started immediately after the first heart sound. (3) Mitral regurgitant flow was often distributed from the entire mitral orifice over the entire or the posterior half of the left atrium in the cases with systolic anterior motion. In the cases without systolic anterior motion the regurgitation was usually localised near the mitral orifice. These features differ from those of regurgitation usually seen in rheumatic mitral valve disease and idiopathic mitral valve prolapse. (4) The Doppler technique and left ventriculography were equally efficient in detecting mitral regurgitation. (5) The early systolic component of the murmur of hypertrophic myopathy is considered to result in the main from concomitant mitral regurgitation, but not from turbulent blood flow in the left ventricular outflow tract, so that in cases with mitral regurgitation as a complication, mitral regurgitation may also contribute to the development of the midsystolic portion of the systolic murmur, while the main origin of this portion of the murmur is the left ventricular outflow obstruction.