Difference in myocardial characteristics between hypertrophic cardiomyopathy and myocardial hypertrophy due to essential hypertension

To investigate the qualitative difference in myocardial hypertrophy that exists between hypertrophic cardiomyopathy (HCM) and essential hypertension (HT), we measured the mean wall thickness (MWT), the early diastolic time intervals (IIA-MVO time: from the second heart sound to the point of mitral valve opening, MVO-O time: from MVO to the O point of apexcardiogram) and the MVO-O/IIA-MVO ratio. The MWT in HCM and HT was measured by biventriculogram and echocardiogram, respectively. The MWT showed no significant difference between HT (13.1 +/- 3.0 mm) and non-obstructive type of HCM (14.8 +/- 3.7), but the MWT in obstructive type (1.08 +/- 0.24) was significantly thinner than that in HT. As the MWT increased, both IIA-MVO and MVO-O time were prolonged in both groups. But the mode of prolongation was quite different. In HT, the prolongation of the IIA-MVO time was almost always greater than that of the MVO-O time. In HCM, the prolongation of the latter was greater than that of the former. The MVO-O/IIA-MVO ratio in HT was significantly less than that in normal subjects, but those in HCM were significantly greater. These findings suggest that the differences in the early diastolic time intervals between HCM and HT are not due to the magnitude of the left ventricular hypertrophy, but due to myocardial characteristics.     

高血压所致左心室肥厚与肥厚型心肌病体表心电图和超声心动图的鉴别要点

目的 比较高血压所致左心室肥厚与肥厚型心肌病（HCM）患者体表心电图及超声心动图参数之间的差异，探讨体表心电图对二者鉴别诊断的临床应用价值。 方法 收集高血压致左心肥厚（H-LVH）患者，HCM患者及正常对照各49例。常规测量心电图中的P波时限、QTC时限，QRS波时限、异常q波数量、R波及S波振幅和ST-T与QRS波方向一致率，超声心动图中测量E/A、左室射血分数（LVEF）、室间隔厚度、左房内径（LA）、左心室收缩末期左右径（LVs左右径）、左心室舒张末期左右径（LVd左右径）、左心室收缩末期前后径（LVs前后径）、左心室舒张末期前后径（LVd前后径）、左心室收缩末期长轴（LVs长轴）、左心室舒张末期长轴（LVd长轴）等参数，比较3组之间的差异。 结果 HCM组患者与H-LVH组患者比较，最大左心室室壁厚度显著增厚，LVEF显著升高（均P<0.05），而HCM每博排出量（SV）、LVs左右径、LVd左右径、LVs前后径、LVd前后径、LVd长径显著小于H-LVH（均P<0.05）；心电图提示，HCM组患者II，III，Avf V1 V2导联R波与S波电压之和，QTC时限显著高于H-LVH组患者（P<0.01）；HCM患者异常Q波数量以及III、aVR导联ST-T与QRS波方向一致率显著高于H-LVH组（P<0.01）。 结论 超声心动图可从左心室最大室壁厚度及肥厚特征鉴别HCM患者和H-LVH患者；体表心电图鉴别二者需结合QRS波振幅之和，QTC时限，II、V4导联异常Q波数量及导联ST-T与QRS波方向在V2、V3、V6导联的一致率4个参数。     

Different coronary blood flow increase in left ventricular hypertrophy due to hypertension compared to hypertrophic cardiomyopathy at elevated heart rate.

Coronary vasodilator reserve (CVR) is reduced in patients with left ventricular hypertrophy (LVH). However, it is not clear whether there is any difference between the coronary blood flow increase in LVH caused by hypertension (HTH) and that caused by hypertrophic cardiomyopathy (HCM) when the heart rate increases. In this study, 16 subjects with HTH, 10 subjects with HCM, and 10 subjects with normotension (NT) were investigated. Average peak velocities at rest, at pacing, and at dilatation were measured using a Doppler catheter placed at the left descending coronary artery to calculate coronary blood flow (CBF) and CVR. CVR at rest was identical in the HTH and HCM groups, and in both cases was lower than the resting CVR in NT subjects. There were significant differences in the CVR values at a pacing rate of 120 beats/min among the groups. These values were lowest in HCM, highest in NT, and intermediary in HTH subjects. And the percent increase in CBF in HCM at that pacing rate was higher than that in HTH (p < 0.05) or NT (p < 0.05). There was no difference in the percent increase in CBF at this pacing rate between the HTH and NT groups. The effects of elevated heart rate on the percent increase in CBF were different between the HTH and HCM groups. We conclude that cardiac hypertrophy has qualitatively different effects on coronary circulation depending on whether patients have HTH or HCM.     

Left ventricular hypertrophy in Caucasian master athletes: Differences with hypertension and hypertrophic cardiomyopathy

AIM: To study, by conventional echocardiography, left ventricular remodelling and function in master athletes, hypertension and hypertrophic cardiomyopathy. METHODS: We studied 30 master athletes (MA; soccer players; mean age 43.9+/-5.9), 24 subjects with essential hypertension (HYP; 46.6+/-6), 20 patients with hypertrophic cardiomyopathy (HCM; 42.2+/-9) and 30 normal individuals (CG; 43.4+/-5). An integrated M-mode/two-dimensional echocardiographic analysis was performed to determine chambers dimensions, relative wall thickness (RWT) and left ventricular mass (LVM), indexed to height in meters raised to the power of 2.7 (LVM/h(2.7)). Cut-off levels for LVM/h(2.7) and RWT were defined to assess 4 different patterns of LV geometric remodelling. In addition, we measured indexes of global systolic performance and indexes of global diastolic function. RESULTS: LV wall thickness and LV end-diastolic dimensions were higher in MA than controls, but significantly lower than other groups. LVH/h(2.7) was increased in 79% of HYP and in 95% of HCM, but was within the normal limits in MA. LV geometry was normal in 22 out of 30 MA (73%), while the remaining (8 athletes, 27%) showed a concentric remodelling. Systolic function (FS and EF) was normal in MA, but was slightly reduced in HYP and increased in HCM. Analysis of diastolic function showed an abnormal relaxation pattern in all HYP and 95% of HCM, but was normal in all MA. The ratio between peak filling rate and stroke volume (PFR/SV), a relatively independent index of diastolic function, was significantly greater in hypertensive patients with normal LV remodelling compared to those without it (4+/-0.39 vs. 4.91+/-0.19; P = 0.0002). CONCLUSION: MA showed lower values of wall thickness, LV dimensions and LV mass compared with HYP and HCM. Despite an abnormal remodelling, all the athletes showed a normal systolic and diastolic function. The differential diagnosis between MA, HYP and HCM is feasible by accurate, comprehensive standard Doppler echocardiography.     

Mitral valve abnormalities in decedents of sudden cardiac death due to hypertrophic cardiomyopathy and idiopathic left ventricular hypertrophy

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Asymmetrical septal hypertrophy in patients with hypertension: A type of hypertensive left ventricular hypertrophy or hypertrophic cardiomyopathy combined with hypertension?

To determine whether asymmetrical septal hypertrophy (ASH) in patients with essential hypertension (HT) is a type of hypertensive left ventricular (LV) hypertrophy or hypertrophic cardiomyopathy (HCM) combined with HT, we investigated a group of 7 hypertensive patients with ASH compared with 12 HCM patients and 10 healthy controls using radionuclide angiography and right ventricular endomyocardial biopsy. The LV time-volume curve and its first and second derivative curves were constructed from cardiac output and time-activity curves constructed by combined forward and reverse-gating from the R wave. The LV wall thickness and ejection fraction were significantly greater in both the HT and HCM groups than in the control group, whereas there were no differences in these indices between the HT and HCM groups. Rapid filling volume index and rapid filling fraction showed significantly lower values in the HCM group than in the control group (p < 0.005). In contrast to the HCM group, these indices in the HT group did not differ from those in the control group. The time to peak filling rate was prolonged in the control, hypertension, and HCM groups in increasing order. Histopathological study revealed a higher incidence of myocardial cell disarray in the HCM than in the HT group. The above results suggest that ASH in hypertensive patients is a type of hypertensive LV hypertrophy.     

Regional myocyte hypertrophy and increased interstitial myocardial fibrosis in hypertrophic cardiomyopathy

The purpose of this study was to determine if the thickened cardiac walls of patients with hypertrophic cardiomyopathy (HC) are due to increased size or number of myocytes or increased amounts of fibrous tissue. Eight patients, aged 18 to 42 years, who died from complications of HC and 8 age-matched control subjects without heart disease were studied. A 1.5-cm3 block of tissue was removed from the left ventricular free wall, right ventricular free wall and ventricular septum (VS). Each region of each wall was evaluated for fibrous tissue by point counting; cell diameter was measured using an ocular micrometer disc. Cell layers were counted across the walls. The results revealed that increased cell size, cell layers and fibrous tissue are characteristic of HC, but only in the VS are all 3 significantly increased. The fibrous tissue was most extensive in the VS (19 +/- 9%), but it was more extensive than in the control subjects in all 3 walls. Cell diameters were largest in the layers closest to the left ventricular cavity.     

Progressive left ventricular remodeling in patients with hypertrophic cardiomyopathy and severe left ventricular hypertrophy

OBJECTIVES: The aim of this study was to determine the natural history of patients with hypertrophic cardiomyopathy (HCM) and severe left ventricular hypertrophy (LVH) (i.e., maximal left ventricular wall thickness [MLVWT] >/=30 mm) and whether changes in cardiac morphology influence the course of the disease. BACKGROUND: Severe LVH is common in young and rare among elderly patients with HCM. This has been explained by a high incidence of sudden death. We hypothesized that this age-related difference might be explained by left ventricular wall thinning. METHODS: A total of 106 (age 33 +/- 15 years; 71 males) consecutive patients with severe LVH underwent history taking, examination, electrocardiography, echocardiography, cardiopulmonary exercise testing, and Holter analysis. Survival data were collected at subsequent clinic visits or by communication with patients and their general practioners. In order to assess morphologic and functional changes, 71 (67.0%) patients (mean age 31 +/- 15 years; 47 males) followed at our institution underwent serial (>/=1 year) assessment. RESULTS: Of the 106 patients, the majority (78 [71.6%]) were <40 years of age. During follow-up (92 +/- 50 months [range 1 to 169]), 18 (17.0%) patients died or underwent heart transplantation (13 sudden cardiac deaths, 2 heart failure deaths, 1 heart transplantation, 1 stroke, 1 postoperative death). Five-year survival from sudden death was 90.1% (95% confidence interval [CI] 84.0% to 96.3%), and that from heart failure death or transplantation was 97.7% (95% CI 94.5 to 100). In patients serially evaluated over 85 +/- 51 months, there was an overall reduction in MLVWT of 0.6 mm/year (95% CI 0.31 to 0.81, p = 0.00004). Wall thinning >/=5 mm was observed in 41 patients (57.7%; age 35 +/- 13 years; 28 males). On multivariate analysis, the follow-up duration only predicted wall thinning (0.6 mm/year, 95% CI 0.38 to 0.85, p < 0.00001). CONCLUSIONS: Left ventricular remodeling is common in patients with severe LVH and contributes to the low prevalence of severe LVH seen in middle age and beyond.     

Relation between extent of left ventricular hypertrophy and age in hypertrophic cardiomyopathy

This investigation was undertaken to determine whether a relation could be identified between left ventricular wall thickness and age in a large population of symptomatic patients with hypertrophic cardiomyopathy. Extent of left ventricular hypertrophy was assessed with two-dimensional echocardiography in 173 patients with hypertrophic cardiomyopathy who ranged in age from 21 to 74 years (mean 45) and had mild to severe cardiac symptoms. The overall study group was classified into five age subgroups (each corresponding to a decade); maximal left ventricular wall thickness and wall thickness index (a quantitative expression of the overall extent of hypertrophy) were assessed in each group. These two indexes were significantly higher in patients 21 to 30 years of age than in patients in each of the other four older age groups. The two indexes of left ventricular hypertrophy were also significantly higher in patients 31 to 40 years of age than in patients who were 61 to 74 years old. Multivariate regression analysis showed that the relation between wall thickness and age was not influenced by other clinical variables such as severity of symptoms, presence of subaortic obstruction, left ventricular cavity dimension and gender. In conclusion, the findings indicate that, in a population of symptomatic adult patients with hypertrophic cardiomyopathy, left ventricular hypertrophy is considerably more severe in younger than in older patients and that there is an inverse relation between left ventricular wall thickness and age.     

老年肥厚型心肌病与高血压左室肥厚患者临床特点的比较

目的 分析老年肥厚型心肌病与老年高血压左室肥厚患者的临床特点.方法 回顾性分析老年肥厚型心肌病患者(35例)与老年高血压左室肥厚患者(35例)的症状和体征及心电图、超声心动图的差异.结果 老年肥厚型心肌病患者均无高血压史.两组年龄、性别、脑血管病史及肥厚型心肌病家族史比较,差异均无统计学意义(均为P＞0.05).老年肥厚型心肌病患者中,晕厥者5例(14.3%),高血压左室肥厚患者中,无晕厥者,2组比较,差异有统计学意义(P＜0.05).老年肥厚型心肌病患者中无心脏杂音者9例(25.7%),明显少于高血压左室肥厚患者[23例(65.7%),P＜0.05].心电图示:老年肥厚型心肌病患者中,有异常Q波者10例(28.6%),较高血压左室肥厚患者的1例(2.9%)多(P＜0.05).老年肥厚型心肌病患者中心房颤动(房颤)及ST-T改变者分别为11例(31.4%)及34例(97.1%),明显多于高血压左室肥厚患者的3例(8.6%)及26例(74.3%),均为P＜0.05.超声心动图示:老年肥厚型心肌病患者的左室后壁厚度为(9.5±1.1)mm,明显薄于高血压左室肥厚患者的(12.6±1.0)mm(P＜0.01),左房内径老年肥厚型心肌病患者为(41.6±6.3)mm,高血压左室肥厚患者为(38.6±5.5)mm,两组差异有统计学意义(P＜0.05);老年肥厚型心肌病患者二尖瓣血流频谱E/A＜1者15例(42.9%),明显少于高血压左室肥厚患者的32例(91.4%),P＜0.05.老年肥厚型心肌病患者有主动脉瓣钙化者7例(20.0%),高血压左室肥厚患者20例(57.1%),二者差异有统计学意义(P＜0.05),室间隔厚度、左室内径与射血分数2组相似(均为P＞0.05).结论 老年肥厚型心肌病患者临床表现有晕厥者多,心脏有明显的杂音,心电图有异常Q波及房颤者较多,超声心动图显示左室不对称性肥厚多;高血压左室肥厚患者左室肥厚多为对称性,合并主动脉瓣钙化者多.     

Relation between extent of left ventricular hypertrophy and occurrence of ventricular tachycardia in hypertrophic cardiomyopathy

This study was undertaken to determine whether the occurrence of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HC) is related to the magnitude and extent of left ventricular (LV) hypertrophy. Extent of LV hypertrophy was assessed using 2-dimensional echocardiography in 30 patients with HC in whom VT had been documented on 24-hour ambulatory electrocardiographic (ECG) monitoring, and the extent of LV hypertrophy in these patients was compared with that of a control group of 61 patients with HC who had normal ambulatory ECG recordings. Severe LV hypertrophy, involving at least 3 of the 4 LV segments, occurred significantly more often in patients with documented VT (16 of 30, 53%) than in those with normal ambulatory ECG findings (13 of 61, 21%; p less than 0.002). Conversely, mild LV hypertrophy, involving only 1 LV segment, occurred significantly less often in patients with VT (5 of 30, 17%) than in the control subjects (32 of 61, 52%; p less than 0.001). Moderate LV hypertrophy, involving 2 of the 4 LV segments, occurred about as frequently in patients with VT (9 of 30, 30%) as in patients with normal ambulatory ECG findings (16 of 61, 26%; p greater than 0.05). In addition, the LV wall thickness index, a quantitative measure of overall extent of LV hypertrophy, was also significantly higher (thereby indicating a greater magnitude of hypertrophy) in patients with documented VT (72 +/- 17 mm) than in those with normal ambulatory ECG recordings (61 +/- 14 mm; p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

肥厚型心肌病患者危险性室性心律失常分析

目的　探讨肥厚型心肌病左心室肥厚的程度与室性心律失常发生的关系。方法　对 60例患者分别作多普勒、二维超声及2 4h动态心电图检测 ,对照分析危险与非危险性室性心律失常的左心室肥厚的程度、左心室流出道梗阻、舒张功能情况。结果　危险性与非危险性室性心律失常的患者分别为 2 3例 ( 38.3% )与 37例 ( 61.7% ) ,两组间左心室壁厚度、左心室舒张功能存在显著差异 ,前者异常程度严重 ;梗阻型较非梗阻型患者的危险性室性心律失常明显增加。结论　肥厚型心肌病危险性心律失常的发生率与左心室肥厚的程度及流出道梗阻有关