二维斑点追踪成像技术评价胸部放疗后早期左室短轴收缩功能损伤

目的：应用二维斑点追踪成像技术（2D-STI）定量分析左室短轴收缩功能,评价二维斑点追踪成像技术在检出胸部放疗后对心脏早期损伤方面的应用价值。方法：46例接受胸部放疗的恶性肿瘤患者按照放疗进程分为3组：A组：放疗前（对照组）;B组：放疗时间2.5～3周、照射剂量26～30Gy;C组：放疗时间5～6周、照射剂量50～60Gy。测量左心室基底段、中段短轴方向峰值径向应变（RS）及圆周应变（CS）。结果：①C组前壁、前间隔和后壁各节段的RS和CS较A组明显减低（P<0.01）;C组前壁、前间隔和后壁各节段的RS和CS较B组减低（P<0.05）;B组前壁、前间隔和后壁各节段的RS和CS与A组比较无显著性差异（P>0.05）。②下壁、侧壁和后间隔各节段的RS和CS在各组之间无显著性差异（P>0.05）。结论：研究表明胸部放疗达到一定时间和剂量时,被照心肌组织的RS和CS均比放疗前明显减低,说明已出现心脏局部的收缩功能受损。二维斑点追踪成像技术对评价胸部放疗后的早期心脏损伤具有重要价值。     

三维超声心动图评估发育不良型三尖辦结构的价值

目的 应用三维超声心动图探讨右心室发育不良时三尖辦装置的结构特点.方法 28例诊断为右心室发育不良的患儿,按照三尖辦反流程度分为反流组(三尖辦反流中度及以上)与非反流组(三尖辦反流轻度及以下).18例年龄匹配的正常儿童作为对照组.应用实时三维超声心动图测定右心室容积、三尖辦辦环面积、三尖辦各辦叶的面积以及辦尖至最近乳头肌顶点的距离.测值应用体表面积(USA)进行标化.结果 右心室发育不良患儿组的右心室容积显著低于正常组,三尖辦辦环面积与右心室容积显著相关(r=0.90,P<0.0001).在三尖辦反流组,三尖辦前辦面积与辦环面积的比值较非反流组以及正常组显著增加,而后辦所占比值显著缩小.右心发育不良组各辦尖至相邻乳头肌顶点的距离显著小于正常组.反流组隔辦辦尖至相邻乳头肌距离显著小于非反流组(P=0.0023).结论 三维超声心动图可以用来评估先天性心脏病三尖辦病变.右心室发育不良患儿后辦发育不良以及隔辦腱索偏短可能是三尖辦反流的原因.     

经食管超声心动图在肥厚型梗阻性心肌病心肌切除术中的应用

目的探讨多平面经食管超声心动图(TEE)在肥厚型梗阻性心肌病(HOCM)手术治疗中的应用价值。方法 16例行左室流出道疏通术的HOCM患者,TEE在建立体外循环前测量心肌厚度、左室流出道内径、左室流出道收缩期峰值压力阶差,估测室间隔切除的深度和长度,协助外科医师选择适宜的手术方式;心脏复跳之后即刻判定手术疗效和预后,指导外科医生适时关胸。结果与术前比较,HOCM患者左室流出道疏通术后室间隔厚度、左室流出道压力阶差均下降,而左室流出道内径增宽(均P0.05)。术前9例二尖瓣轻-中度关闭不全,7例二尖瓣中度关闭不全;术后16例二尖瓣前叶前向运动全部消失,仅2例二尖瓣微量反流。术前10例主动脉瓣轻度关闭不全术后即刻消失。结论左室流出道疏通术中TEE能够修正完善术前诊断,提高手术疗效,减少手术并发症。     

多普勒组织成像评价小儿心脏移植术后心功能

目的用超声心动图二维、M型、彩色多普勒及脉冲多普勒组织成像(PW-DTI)等方法对小儿心脏移植术后非排异期心脏的结构、形态、血流、功能等状态进行综合评价，重点探讨PW-DTI对小儿心脏移植术后非排异期心功能评价的意义。方法移植组和对照组各36例，应用超声心动图、PW-DTI测量左室舒张末期内径，室间隔厚度，左室后壁厚度，左室质量，左室短轴缩短率，二、三尖瓣前向血流舒张早、晚期峰值速率及心率；将PW-DTI取样容积置于二尖瓣瓣环水平左室侧壁、室间隔及三尖瓣环水平右室壁采样，获取收缩期和舒张早、晚期PW-DTI运动速度曲线。结果移植组的所有PW-DTI速度曲线参数均较对照组低。二尖瓣瓣环水平左室侧壁舒张早期峰值速率，室间隔及三尖瓣环收缩期峰值速率，舒张早、晚期峰值速率与对照组差异有显著性意义；而其他指标移植组与对照组基本相同。结论PW-DTI速度曲线参数的结果提示心脏移植术后非排异期患儿在常用的心功能指标测值正常时，已存在右室收缩、舒张功能及左室舒张功能的减低，以右心功能减低为明显。PW-DTI是一种敏感、简便的测量小儿心脏移植后左、右心功能的方法．     

彩色多普勒血流显像对缺血性心脏病瓣膜返流机制的探讨

本文利用彩色多普勒血流显像（CDFI）技术分析了108例缺血性心脏病瓣膜返流（MR、AR）的特点。结果表明：缺血性心脏病二尖瓣返流束位置与梗塞区或受累室壁高度相关。四腔心切面显示前外测室壁运动异常的MR返流来多位于左房内侧壁，下壁及后间壁室壁运动异常的MR返流束多位于左房外侧壁。因此缺血性心脏患者MR的主要原因是与左室壁运动异常及二尖瓣环大小有关，“乳头肌功能不全”不代表其解剖意义。AR的主要原因为主动脉瓣的机械磨损、钙化及纤维化。高血压及糖尿病可使本病提前发生。     

胸部小切口心脏直视手术

目的：介绍几种体外循环下胸部小切口心脏直视手术的经验。方法：161例心脏疾病患者采用右腋下、右前外侧胸、胸骨右侧旁及胸骨下段小切口,在体外循环下施行心脏直视手术。病种包括房间隔缺损、室间隔缺损、法乐四联症、二尖瓣狭窄或／并关闭不全、二尖瓣狭窄并三尖瓣关闭不全及其他畸形,包括肺动脉口狭窄、动脉导管未闭及永存左上腔静脉等。结果：术后161例患者中2例（1．2％）分别死于消化道溃疡出血及重型肺炎。1例并发胸骨后出血、Ⅲ度房室传导阻滞、室间隔缺损修补术后残余分流;1例右侧胸腔积液,经处理后均康复出院。结论：以上各小切口开胸行心脏直视刘安全、有效的。术野显露好,病变矫正满意,创伤小,并发症少,痛苦轻,恢复好,美观效果亦好。临床 可根据具体情况选择应用。     

Native mitral valve regurgitation. Proactive management can improve outlook.

Mitral regurgitation is a common valvular abnormality that can result in substantial morbidity. Primary care physicians should maintain a high index of suspicion for this disorder, especially in patients with symptoms of heart failure. The paramount concern is early identification of patients with mitral regurgitation and prompt referral to a cardiologist when symptoms occur or if evidence of ventricular enlargement or reduction in ejection fraction is found. Echocardiography is an invaluable tool in determining the severity of regurgitation, the integrity of the mitral valve apparatus, the extent of left ventricular enlargement, and the ejection fraction. Although no standard medical treatment has been established for mitral regurgitation, use of ACE inhibitors is appropriate. Patients presenting with severe, acute mitral regurgitation from papillary muscle rupture should be evaluated for ischemia and treated expediently. The preferred operative procedure in patients with severe mitral regurgitation and left ventricular dysfunction is mitral valve repair, if possible, or mitral valve replacement with posterior chordal preservation, if feasible.     

Severe mitral regurgitation with right ventricular pacing, successfully treated with left ventricular pacing

A case of severe mitral regurgitation with refractory heart failure, after atrioventricular junction ablation and pacemaker implant, was solved with left ventricular pacing. Mitral regurgitation was related to a change in segmental left ventricular motion during right ventricular pacing.     

双心室起搏与右心室起搏对充血性心力衰竭急性心功能的影响

目的最近研究提示心脏再同步治疗有效地改善了慢性心肌病心力衰竭患者心功能。本研究旨在探讨双心室和右心室起搏对心功能的相对影响。方法 15例慢性心力衰竭患者心功能Ⅲ级,左心室射血分数〈35%,QRS〉130ms和二尖瓣反流。安装心房-双心室再同步起搏器。彩色多普勒超声心动图观察心功能变化。结果急性双心室和右心室起搏并未影响左心室内径和短轴缩短率,也不影响左心室射血速度和排血量。左心室压力上升和下降峰速率无明显变化。等容收缩时间缩短（P〈0.05）,但不影响等容舒张时间。增加Z比例（P〈0.05）。缩短二尖瓣反流时间（P〈0.05）,对二尖瓣环和三尖瓣环运动幅度和峰速率无明显影响。双心室和右心室起搏之间无明显差别。结论双心室起搏改善了慢性心肌病心功能。双心室和右心室起搏无明显差别。双心室起搏是一种有前途的心脏再同步治疗方法。     

Cardiac resynchronization therapy

About 30% of patients with left ventricular systolic dysfunction also have ventricular conduction delays (prolonged QRS duration greater than 0.12 second) most frequently seen as left bundle branch block. This intraventricular conduction delay causes nonsynchronous ventricular activation between the right ventricle and the left ventricle (or dyssychrony), compromising cardiac function. Cardiac resynchronization therapy, or biventricular pacing, is a recent intervention for ventricular dyssychrony that incorporates 3 leads for pacing the right atrium and simultaneous pacing of the right ventricle and left ventricle. Left ventricular lead placement can be difficult to implant because of coronary venous anatomy and can require longer procedure time for the patient. Restoring ventricular synchrony has been shown to decrease septal wall dyskinesis, decrease mitral regurgitation, increase left ventricular filling time, decrease pulmonary capillary wedge pressure, and reverse ventricular modeling.     

Right atrial spontaneous contrast: echocardiographic and clinical features

We describe the clinical and echocardiographic findings in eight patients with right atrial spontaneous echo contrast who were identified from 648 consecutive patients undergoing transesophageal echocardiography. Common findings in these patients were right atrial enlargement (8 patients), tricuspid regurgitation (7 patients), atrial fibrillation or flutter (6 patients), elevated right ventricular pressure (5 patients), moderate or severe mitral valve disease (5 patients), and right to left interatrial shunts (3 patients). Right heart catheterization in three patients showed markedly elevated right atrial, right ventricular, and pulmonary artery pressures. Two patients had thromboembolic events — one patient had recurrent pulmonary emboli, and another patient with an atrial septal aneurysm had recurrent transient ischemic attacks. Right atrial echo contrast is an uncommon finding at echocardiography that is associated with severe right heart dysfunction. It may also be associated with paradoxical or pulmonary embolism.     

Childhood cardiac function after prenatal diagnosis of intracardiac echogenic foci.

OBJECTIVE: To determine whether prenatally diagnosed intracardiac echogenic foci are associated with childhood cardiac dysfunction and persistence. METHODS: Children in whom intracardiac echogenic foci were shown on prenatal sonography at 1 perinatal center underwent echocardiography at ages 2 to 7 years. A single pediatric cardiologist, blinded to the prenatal sonographic intracardiac echogenic focus locations, assessed cardiac function by measuring the left ventricular shortening fraction and myocardial performance index. The presence of tricuspid and mitral valve regurgitation was also sought. The secondary outcome was intracardiac echogenic focus persistence. RESULTS: Twenty-five children, 14 (56%) male and 11 (44%) female, were examined at a mean age +/- SD of 3.0 +/- 1.0 years. Prenatally, 18 children (72%) had left ventricular intracardiac echogenic foci, and 7 (28%) had right ventricular intracardiac echogenic foci. The left ventricular shortening fraction was normal in all children. The overall mean left ventricular myocardial performance index (reference value, 0.36 +/- 0.06), was normal for both children with left ventricular intracardiac echogenic foci (0.36 +/- 0.06) and those with right ventricular intracardiac echogenic foci (0.36 +/- 0.04). Two children with left ventricular intracardiac echogenic foci had an isolated left ventricular myocardial performance index of greater than 2.5 SD above the mean. Trace tricuspid valve regurgitation and mitral valve regurgitation were noted in 13 (52%) and 2 (8%) of the children, respectively, similar to the general population. Left ventricular intracardiac echogenic foci persisted in 16 children (89%), whereas right ventricular intracardiac echogenic foci persisted in 2 (29%) (P = .007). CONCLUSIONS: Prenatally diagnosed intracardiac echogenic foci are often persistent but not associated with childhood myocardial dysfunction.     

Factors Predisposing to the Development of Atrial Fibrillation

Atrial fibrillation (AF) is in most patients (approximately 70%) associated with organic heart disease including valvular heart disease, coronary artery disease, hypertension, hypertrophic cardiomyopathy, dilated cardiomyopathy, and congenital heart disease, mostly atrial septal defect in adults. In many chronic conditions, determining whether AF is the result or is unrelated to the underlying heart disease, remains unclear. The list of possible etiologies also include cardiac amyloidosis, hemochromatosis and endomyocardial fibrosis. Other heart diseases, such as mitral valve prolapse (without mitral regurgitation), calcifications of the mitral annulus, atrial myxoma, pheochomocytoma, and idiopathic dilated right atrium may present with AF. Atrial fibrillation may occur in the absence of detectable organic heart disease, the so-called “lone AF”, in about 30% of cases. The term “idiopathic AF” implies the absence of any detectable etiology including hyperthyroidism, chronic obstructive lung disease, overt sinus node dysfunction, and overt or concealed preexcitation (Wolff-Parkinson-White syndrome), only to mention a few of other uncommon causes of AF. The autonomous nervous system may contribute to the occurrence of AF in some patients. AF occurs commonly. In patients with valvular heart disease, AF is common, particularly when the mitral valve is involved. The occurrence of AF is unrelated to the severity of mitral stenosis or mitral regurgitation but is more common in patients with enlarged left atrium and congestive heart failure. In patients with coronary artery disease, AF occurs predominantly in older patients, males, and patients with left ventricular dysfunction. Important predictive factors of AF include hypertension, left ventricular hypertrophy and diabetes. The risk of the development of AF, in an individual patient, is often difficult to assess. Increasing age, presence of valvular heart disease, and congestive heart failure increase the risk of atrial fibrillation.     

Ventricular Endocardial Right Bifocal Stimulation in the Treatment of Severe Dilated Cardiomyopathy Heart Failure with Wide QRS

PACHÓN, J.C., et al. : Ventricular Endocardial Right Bifocal Stimulation in the Treatment of the Severe Dilated Cardiomyopathy Heart Failure with Wide QRS. The QRS widening by ventricular conventional pacing impairs the systolic and diastolic functions and increases mitral regurgitation. The aim of this study was to compare conventional pacing to an alternative stimulation mode with a narrower QRS using two leads in the RV. Thirty‐nine (25 men, 14 women; mean age 60.1 ± 15.1 years ) dilated cardiomyopathy patients (Chagas' disease [n = 17], coronariopathy [n = 9], AV ablation for tachycardiomyopathy [n = 3], and other [n = 10] ) with cardiac failure (NYHA 3.1 ± 0.8 ), pacemaker indication, and chronic AV block (22 AF) had endocardial pacemaker implantations (27 Biotronik, 12 Guidant). Two RV leads (one septal, one conventional [RV apex] were connected, respectively, to the atrial and ventricular pacemaker plugs. After clinical stabilization they were studied under three stimulation modes in the same session: AAI (septal), VVI (conventional), and ventricular endocardial right bifocal stimulation (VERBS) (DDT/DVI/DDD = AV interval = 15/10 ms). In comparison to conventional pacing, VERBS increased ejection fraction (0.124), cardiac output (19.5%), and peak filling rate (31.0%), and decreased QRS duration (24.7%), left atrium area (11.9%), mitral regurgitation area (32.3%), the diastolic transmitral flow (E/A relation) (19.3%), and the propagation flow time (18.0%) from the mitral valve to the left ventricular apex (tE_col), (P < 0.05). The quality‐of‐life showed an impressive score reduction of 50.4%. The septal stimulation alone showed a less expressive benefit. In severe dilated cardiomyopathy with classic pacemaker indication, VERBS showed significantly better performance than the septal or the conventional stimulation alone. There was a good systolic and a remarkable diastolic improvement causing an important reduction in the quality‐of‐life score.     

Age-related changes in normal human hearts during the first 10 decades of life. Part II (Maturity): A quantitative anatomic study of 765 specimens from subjects 20 to 99 years old

Heart weights, ventricular wall thicknesses, and valve circumferences were measured in 765 autopsy specimens from normal hearts from persons 20 to 99 years old. Body weight was a better predictor of normal heart weight than was body surface area or height, and mean heart weights were greater in men than in women at all ages. When heart weights were indexed (divided by body surface area), the mean values per decade increased significantly in women between the 3rd and 10th decades of life (P less than 0.01) but remained relatively constant with time in men. We found no significant differences in ventricular wall thicknesses between men and women. Although indexed mean values for left and right ventricular wall thicknesses remained relatively constant in all decades, ventricular septal thickness increased significantly between the 3rd and 10th decades of life (P less than 0.001). Beyond the seventh decade of life, the mean ratio of septal to left ventricular free wall thicknesses exceeded 1.20, and the upper 95% confidence limit exceeded 1.50--an important consideration in evaluation of hypertrophic cardiomyopathy in elderly patients. Mean valve circumferences were usually greater in men than in women, but the opposite pertained when values were indexed by body surface area. In both sexes, all indexed mean valve circumferences increased progressively throughout adult life, although this trend was greater for semilunar than for atrioventricular valves. The mean circumference of the aortic valve surpassed that of the pulmonary valve in the 4th decade and approached that of the mitral valve by the 10th decade of life. Thus, in evaluation of annuloaortic ectasia, investigators should take into account the normal age-related changes in aortic valve dimensions.     

Treatment of pacemaker induced severe mitral regurgitation with biventricular pacing in two patients with a normal left ventricular ejection fraction

This report describes two patients who developed severe mitral regurgitation and drug refractory congestive heart failure after implantation of a conventional pacemaker. Both patients had a normal left ventricular ejection fraction. Dramatic long-term improvement occurred following the institution of biventricular pacing that resulted in mild mitral regurgitation. The findings illustrate the benefit of cardiac resynchronization therapy in pacemaker induced left ventricular dyssynchrony causing severe mitral regurgitation and severe congestive heart failure in selected patients with a normal left ventricular ejection fraction.     

健康比格犬左心室壁生物力学特征的超声速度向量成像研究

目的应用超声速度向量成像（VVI）技术评价健康雌性比格犬左心室壁短轴切面不同节段心内、外膜下心肌生物力学特征,探讨其跨壁差异与左心室壁厚度变化的关系。方法以经心外膜超声心动图分别采集25只健康开胸比格犬二尖瓣、乳头肌和心尖水平标准左心室短轴切面3个完整心动周期实时声像图。应用VVI软件提取一个完整心动周期左心室壁3个标准短轴切面整体及其短轴切面18个节段心、内外膜下心肌的径向位移、周向应变和旋转角时间序列参数,计算并比较一个完整心动周期内左心室壁不同节段和不同短轴水平心、内外膜下心肌的最大径向位移（RDmax）、最大周向应变（CSmax）、最大旋转角（RAmax）。计算并比较一个完整心动周期内左心室不同节段和不同水平的室壁最大净增厚值（△Tmax）,心内、外膜下心肌最大应变差（△CSmax）,心内、外膜下心肌最大旋转角差（△RAmax）。相关分析3个不同短轴水平左心室壁的△Tmax与△CSmax、△RAmax。结果①左心室壁心内膜下心肌RDmax、CSmax和RAmax均大于心外膜下心肌（P〈0.05）;②左心室壁△Tmax为心尖〈二尖瓣〈乳头肌水平,△CSmax于乳头肌水平最大,△RAmax于心尖水平最大（P〈0.05）;③3个标准短轴切面左心室壁△CSmax和△RAmax均与△Tmax呈直线相关（r=0.705-0.802,P〈0.001;r=0.697-0.736,P〈0.001）。结论健康犬左心室壁心肌力学状态存在不同水平的跨壁差异;左心室壁心、内外膜下心肌间的周向应变差异和相对周向剪切运动与左心室壁厚度变化密切有关;超声VVI技术有助于揭示犬左心室壁生物力学基本特征。     

Coenzyme Q10 content in different parts of the normal human heart

Summary. Coenzyme Q₁₀ (CoQ₁₀) and citrate synthase (CS) activities were analysed in the myocardium of brain-dead organ donors (14–40 years). Different parts of the heart were studied: right and left auricular appendage, right and left atrium, right ventricle (septum and free wall) and left ventricle (septum, free wall, and papillary muscle). Freeze-dried, dissected myocardial samples were analysed for CoQ₁₀ content by HPLC and CS activity by fluorometric technique. CoQ₁₀ content in the normal human myocardium was lowest in auricular appendages and atria (0·25 ±0·06 mg×g^-1 dry muscle), intermediate in right ventricle (0·37±0·05 mg×g^-1 dm) and highest in left ventricle (0·42±0·07 mg×g^-1 dm). CS activity showed the same relationship between these locations as CoQ₁₀. The results suggest that there exist differences in CoQ₁₀ content between different parts of the normal human myocardium. These differences were closely related to the differences in CS activity between corresponding parts. The differences between different parts of the heart may be related to divergent work demand, and the constant relationship between CS and CoQ₁₀ may be related to their coupling to the mitochondrial oxidative metabolism.     

Improvement in left ventricular diastolic filling by septal myectomy in hypertrophic cardiomyopathy

Abnormalities in left ventricular diastolic function or filling are considered to be responsible for some of the symptoms in patients with hypertrophic cardiomyopathy. To clarify whether the abnormalities in left ventricular diastolic filling are improved by septal myectomy, 13 patients with hypertrophic cardiomyopathy and intracavitary pressure gradient were studied preoperatively and postoperatively by use of pulsed Doppler echocardiography. Peak early diastolic filling velocity (E), the ratio of peak early diastolic filling to peak atrial filling velocities (E/A ratio), and deceleration time were measured from the transmitral flow velocity pattern before and after septal myectomy. Although E and E/A ratio did not change after septal myectomy, deceleration time significantly shortened from 314 +/- 72 to 271 +/- 53 milliseconds (n = 10; p less than 0.05). Further, if seven patients with significant changes in heart rate (greater than 30%) or in the Doppler-determined severity of mitral regurgitation (more than one degree) were excluded (because these parameters may effect E and E/A ratio), there were also significant changes in E (81 +/- 21 versus 98 +/- 25 cm/sec, p less than 0.05) and in E/A ratio (0.84 +/- 0.17 versus 1.14 +/- 0.33, p less than 0.05). Because left ventricular systolic function has been demonstrated to remain constant or to decrease by most measures after septal myectomy, relief of some symptoms may be largely the result of the improvement in diastolic filling suggested by these criteria.     

肥厚型心肌病并心力衰竭患者心肌扩张性及限制性改变对心脏结构及功能的影响

【目的】探讨肥厚型心肌病并心力衰竭患者心肌的扩张性及限制性改变对患者心脏结构及功能的影响。【方法】选取2013年2月至2018年2月解放军第42医院和昆明医科大学附属延安医院接诊的82例肥厚型心肌病患者,根据患者入院时心脏彩超检查结果分为扩张组(n=56),限制组(n=26),所有入选患者均行经胸超声心动图检查和心脏核磁共振检查,采用统计学方法对比分析两组患者左心房前后径(LAD)、左心室射血分数(LVEF)、最大左室壁厚度(LVWT)、左心室舒张末期内径(LVEDD)、左心房扩大患者比例、不同部位心室壁肥厚患者比例及不同部位心室壁延迟强化患者比例等结果。【结果】扩张组平均年龄小于限制组,男性比例明显高于限制组,差异有统计学意义(P<0.05);两组患者入院时心率和血浆NT-proBNP水平比较,差异无统计学意义(P>0.05);两组患者LAD、二尖瓣关闭不全比例、左心房扩大比例以及右心室扩大比例之间无明显差异(P>0.05),扩张组LVEF、LVWT、三尖瓣关闭不全比例以及左右心房均扩大比例明显低于限制组,LVEDD、LVWT<11mm比例以及LVEF<50%比例均明显大于限制组,差异有统计学意义(P<0.05)。扩张组最大心室壁厚度、室间隔和部分左心室游离壁肥厚比例以及局限于室间隔或心尖部心室壁延迟强化比例均低于限制组,苹纯室间隔肥厚、室间隔和左心室游离壁延迟强化比例均高于限制组,差异有统计学意义(P<0.05)。【结论】肥厚型心肌病并心力衰竭患者心肌的扩张性及限制性改变对心脏结构及功能有显著影响,其中心肌纤维化程度和心室壁肥厚部位是导致限制性和扩张性心肌病改变的重要因素。