Effect of dobutamine stress on basal septal tissue dynamics in hypertensive patients with basal septal hypertrophy

Left ventricular outflow tract (LVOT) obstruction has been classically observed in hypertrophic cardiomyopathy in which the LVOT obstruction is associated with asymmetric septal hypertrophy producing a systolic pressure gradient across the LVOT. Basal septal hypertrophy (BSH) with hypertension may result in dynamic LVOT obstruction as well. It was suggested that regional hypertrophy may be related to enhanced ventricular dynamics.     

Flow velocity distributions in the left ventricular outflow tract and in the aortic annulus in patients.with localized basal septal hypertrophy

Background The velocity distributions in the left ventricularoutflow tract and in the aortic annulus in normal subjects andcertain cardiac patients are skewed, with the highest velocityalong the anterior wall and septum. An abnormal anatomical structureof the interventricular septum changes the shape of the leftventricular outflow tract, and may consequently change the patternof velocity distribution. Methods The cross-sectional velocity distributions in the leftventricular outflow tract and in the aortic annulus were constructedby using Doppler colour flow mapping in nine patients with localizedbasal septal hypertrophy, and in 10 normal subjects. The apicallong axis view was used. Results In the studied patients, the velocity distributionsin the left ventricular outflow tract and in the aortic annuluswere skewed in a different way from those in normal subjects.The relative location of the maximal velocity on the cross-sectionaldiameter of the flow channel changed from one level to another.At the point of maximal basal septal hypertrophy, the velocitydistribution was most skewed with the highest velocity alongthe anterior wall (e.g. basal septum). Distal to this level,the highest velocities of the skewed velocity profiles weregradually located closer to the central part of the flow channel.According to the time-velocity integral profile at the levelof the aortic annulus, the pattern of skewness (in terms ofthe difference of the average time-velocity integrals betweenthe anterior and posterior halves of the diameter) was significantlydifferent between the normal and patient groups (5.51±3.55cmvs 0.03±2.07 cm; P<0.01), while the extent of skewness(in terms of the ratio of the maximal to the cross-sectionalmean time-velocity integrals) was close between two groups (1.36±0.28vs 1.27±013; P>005). Conclusion Localized basal septal hypertrophy significantlyaffects velocity distributions in the left ventricular outflowtract and in the aortic annulus.     

Basic echocardiographic features of patients with latent left ventricular outflow tract obstruction without left ventricular hypertrophy

Left ventricular outflow tract obstruction (LVOTO) is commonly observed in patients with hypertrophic cardiomyopathy (HCM) or left ventricular hypertrophy (LVH). While some patients develop LVOTO at rest, it can also be provoked by physical exertion, and hence termed latent LVOTO (L-LVOTO). Recent reports demonstrated that L-LVOTO develops not only in LVH patients, but also in patients without LVH (non-LVH). However, the prevalence and clinical prognosis of non-LVH patients with L-LVOTO are not yet elucidated. In this study, we retrospectively investigated the echocardiographic features of patients with malignancy who underwent dobutamine stress echocardiography (DSE) to evaluate preoperative cardiac risk. One hundred ninety-nine patients were found not to have LVH or coronary artery disease. Among them, 106 patients exhibited L-LVOTO after DSE. We next compared the baseline echocardiographic features of L-LVOTO (+) patients with those of L-LVOTO (-) patients, and identified the left ventricular outflow tract (LVOT) ratio (systolic LVOT diameter/diastolic LVOT diameter) as a significant predictor of L-LVOTO. An LVOT ratio ≤ 0.83 was the best cutoff value to detect the presence of L-LVOTO, with a sensitivity of 81.1% and specificity of 80.6%. Overall, L-LVOTO was found to develop in almost half of non-LVH patients with malignancy. In addition, the baseline LVOT ratio was strongly related to the presence of L-LVOTO in non-LVH patients. Therefore, patients with dynamic LVOT narrowing may benefit from DSE to detect the presence of L-LVOTO.     

Impaired left ventricular synchronicity in hypertensive patients with ventricular hypertrophy

OBJECTIVES: The influence of left ventricular hypertrophy (LVH) on left ventricular synchronicity, and the prevalence of left ventricular dyssynchrony in hypertensive patients with LVH are unknown. The purpose of this study was to determine the influence of LVH on left ventricular synchronicity in hypertensive subjects. METHOD: Tissue Doppler imaging (TDI) was performed in 115 hypertensive and 30 control individuals. Hypertensive patients were divided into a LVH group and a non-LVH group according to the left ventricular mass index (LVMI). Diastolic and systolic asynchrony was determined by measuring the maximal differences in time to peak myocardial systolic contraction (Ts-max) and early diastolic relaxation (Te-max) between any two of the left ventricular segments and the standard deviation of time to peak myocardial systolic contraction and early diastolic relaxation of all 12 segments. RESULTS: Ts-max was greater in both the non-LVH and LVH groups than in controls, (96.68 +/- 26.21 versus 79.30 +/- 25.19 versus 53.20 +/- 15.24 ms, both P < 0.001) and in the LVH group than in the non-LVH group (96.68 +/- 26.21 versus 79.30 +/- 25.19 ms, P < 0.01). Te-max was prolonged in both patient groups, being most advance in the LVH group (67.39 +/- 11.01 versus 57.18 +/- 11.42 versus 46.72 +/- 13.24 ms, both P < 0.001 versus control group and P < 0.001 versus non-LVH group). LVH patients had shown a greater prevalence of both systolic and diastolic asynchrony than non-LVH patients. A Ts-max value greater than 88 ms had 68% sensitivity and 71% specificity for detecting hypertensive patients with LVH. CONCLUSION: Left ventricular systolic synchronicity was impaired in hypertensive patients with LVH. TDI was shown to be useful for the detection of myocardial abnormalities in such patients.     

Posterior deviation of left ventricular outflow tract septal components without ventricular septal defect.

OBJECTIVE: To describe 11 patients with narrowing of the left ventricular outflow tract caused by angular posterior deviation of both the outlet septum and the upper part of trabecular septum, which was diagnosed by cross sectional echocardiography in all and confirmed by angiocardiography in seven. RESULTS: Four patients had a subaortic systolic pressure gradient ranging from 23 to 70 mm Hg by Doppler echocardiography; cardiac catheterisation showed a significant (60 and 104 mm Hg) systolic pressure gradient in two. In four cases aortic regurgitation and two tricuspid pouches were shown by Doppler echocardiography, angiocardiography, or both. Four cases had a ridge at the angulation point on echocardiographic examination. Three patients were operated on for systolic pressure gradients of the left ventricular outflow tract and one for severe aortic regurgitation. There was proliferation of collagen-rich fibrous tissue in the subendocardial region on histopathological examination of the myectomy material. A ventricular septal defect had been diagnosed previously by contrast echocardiography in one patient; thus ventricular septal defects may close spontaneously over a period of time including fetal life. A subaortic ridge was detected in one patient at follow up. CONCLUSIONS: Deviation of the outlet and trabecular septa should be considered as a cause of ventricular outflow tract obstruction even when no ventricular septal defect is present.     

Effect of dobutamine on regional diastolic left ventricular asynchrony in patients with left ventricular hypertrophy.

Dobutamine improves systolic as well as diastolic function, but its effect on left ventricular (LV) asynchrony is unknown. An on-line automated segmental motion analysis (A-SMA) system was developed, based on an automatic border detection technique, to evaluate the effect of dobutamine on LV asynchrony in patients with LV hypertrophy (LVH). Low dose (5 microg x kg (-1) x min(-1)) dobutamine stress echocardiography was performed in 15 patients with LVH and in 15 healthy subjects. Short-axis LV views were obtained and divided into 4 wedge-shaped segments using A-SMA. The time - area curve and its first derivative curve in each segment were displayed. Total normalized peak filling rates (nPFR) were obtained. Systolic and diastolic asynchronies were assessed from the coefficient of variation (CV) of the regional time intervals from end diastole to the peak ejection rate (T-PER), and from end systole to the peak filling rate (T-PFR), respectively. At baseline, the CV of T-PER and T-PFR in patients with LVH were greater than those in healthy subjects (CV-T-PER: 18.8+/-9.2 vs 9.6+/-4.3%, CV-T-PFR: 19.5+/-7 vs 8.1+/-4.1%, both p<0.01). During dobutamine infusion, differences among groups at baseline disappeared and systolic and diastolic asynchronies improved (CV-T-PER: 7.3+/-4.8 vs 5.7+/-2.1%, CV-T-PFR: 6.8+/-3.5 vs 5.1+/-1.3%, both p>0.05). Total nPFR increased (from 3.2+/-1.0 /s to 5.6+/-1.3 /s, p<0.01) with dobutamine infusion in patients with LVH. Dobutamine improved LV diastolic asynchrony, as evaluated by A-SMA, in patients with LVH demonstrating that the lusitropic effect of dobutamine improved LV regional diastolic asynchrony, playing an important role in the improvement of global LV diastolic filling.     

Impaired left ventricular functional reserve in hypertensive patients with left ventricular hypertrophy

To determine whether patients with hypertension and especially those with left ventricular hypertrophy have subtle changes in cardiac function, we measured the increase in left ventricular ejection fraction and in systolic blood pressure to end-systolic volume index ratio with exercise in 40 hypertensive patients and 16 age-matched normotensive volunteers. Twenty-two hypertensive patients without hypertrophy had normal end-systolic wall stress at rest and exercise responses. In contrast, the 18 patients with echocardiographic criteria for left ventricular hypertrophy demonstrated a significant increase in end-systolic wall stress at rest compared with normal subjects (69 +/- 16 vs. 55 +/- 15 10(3) x dyne/cm2, p less than 0.05) despite having normal resting left ventricular size and ejection fraction. In patients with left ventricular hypertrophy, the increase in ejection fraction with exercise was less than in the normotensive control subjects (7 +/- 7 vs. 12 +/- 8 units, p less than 0.05), and delta systolic blood pressure to end-systolic volume with exercise was reduced (3.3 +/- 3.8 vs. 8.3 +/- 7.7 mm Hg/ml/m2, p less than 0.05). The hypertensive patients with hypertrophy displayed a shift downward and to the right in the relation between systolic blood pressure to end-systolic volume ratio and end-systolic wall stress compared with control subjects and hypertensive patients without left ventricular hypertrophy. Thus, hypertensive patients with left ventricular hypertrophy by echocardiography and normal resting ejection fraction exhibit abnormal ventricular functional responses to exercise. This finding may have implications in identifying patients at higher risk for developing heart failure.     

伊贝沙坦对高血压左室肥厚患者的左室结构的影响

目的 研究伊贝沙坦对高血压左室肥厚（LVH）患者的左室结构的影响。方法 60例原发性高血压左室肥厚患者随机分为2组：治疗组每天口服伊贝沙坦150mg，对照组每天口服氨氯地平5mg。平均12个月，观察用药后血压、左室结构的变化。结果 用药后2组收缩压（SBP）和舒张压（DBP）均显著降低（P〈0．01）；室间隔厚度（IVST）及左室后壁厚度（LYPWT）均变薄（P〈0．01），左室重量指数（LYMI）明显减少（P〈0．01），对照组各项指标无明显变化（P〈0．05）。结论 对原发性高血压左室肥厚的患者，长期应用伊贝沙坦具有良好降压效果，同时还可逆转LVH，改善患者预后。     

Heart failure in hypertensive patients with left ventricular hypertrophy

Left ventricular hypertrophy (LVH) is supposed to be a useful marker of cardiovascular complications during the course of hypertension. Authors compared the presence of heart failure, left ventricular diastolic dysfunction and chronic atrial fibrillation in hypertensive patients with and without left ventricular hypertrophy defined by echocardiography. Hospital records of 192 hypertensives treated in our medical department during years 1996-1999 were analysed. Left ventricular hypertrophy was defined by echocardiography (Penn convention) as left ventricular mass index > 134 g/m2 in men and > 110 g/m2 in women. Presence of LVH was found in 128 patients (mean age 65.9 years), absence of LVH in 64 patients (mean age 64.8 years). Both groups of hypertensives were matched by demographic parameters, by the presence of hyperlipidemia, by smoking habits. Hypertensive patients with left ventricular hypertrophy were more often treated by ACE inhibitors. There were statistically significant more patients with heart failure, left ventricular diastolic dysfunction and chronic atrial fibrillation in LVH-positive patients than in LVH-negative once. There was also statistically significant lower ejection fraction (50.3 +/- 11.4% vs 56.5 +/- 7.4%) in LVH-positive patients than in LVH-negative once. Left ventricular hypertrophy in patients with hypertension brings usually a complicated course of the disease with a high contribution to the development of chronic heart failure.     

Morphology of left ventricular outflow tract structures in patients with subaortic stenosis and a ventricular septal defect.

OBJECTIVE--To compare the incidence and prognosis of subaortic stenosis associated with a ventricular septal defect and to define the morphological basis of subaortic stenosis. DESIGN--Presentation and follow up data on 202 patients with subaortic stenosis seen at the Royal Liverpool Children's Hospital between 1 January 1960 and 31 December 1991 were reviewed. Survivors were traced to assess their current clinical state. Necropsy specimens of 291 patients with lesions associated with subaortic stenosis were also examined. RESULTS--In the clinical study; 65 (32.1%) of the 202 patients with subaortic stenosis had a ventricular septal defect (excluding an atrioventricular septal defect). 32 of these patients had a short segment (fibromuscular) subaortic stenosis. 33 had subaortic stenosis produced by deviation of muscular components of the outflow tracts. In 17 patients (51.5%) this was caused by posterior deviation or extension of structures into the left ventricular outflow tract, resulting in obstruction above the ventricular septal defect. In the other 16 patients (48.5%) there was over-riding of the aorta with concordant ventriculoarterial connections, (without compromise to right ventricular outflow) producing subaortic stenosis below the ventricular septal defect. Additional fibrous obstruction occurred in 39% of the patients with deviated structures. The age at presentation was lower (P < 0.01) in patients with deviated structures (median (range) 0.4 (0 to 9.2) months) than in those with short segment obstruction (median (range) 4.2 (0 to 84.9) months). The incidence of aortic arch obstruction was higher (P < 0.002) in patients with deviated structures than in those with short segment obstruction (38%). In the morphological study 35 pathological specimens showed obstructive muscular structures in the left ventricular outflow tract either above or below the ventricular septal defect. 16 had either posterior deviation of the outlet septum or extension of the right ventriculoinfundibular fold, or both of these together into the left ventricle. 19 had anterior deviation of the outlet septum into the right ventricle with overriding of the aorta (without compromise to right ventricular outflow). The earliest age at which additional fibrous obstruction was seen was 9 months. The aortic valve circumference was small in 18% of specimens. FOLLOW UP--The median (range) duration of follow up in survivors from the clinical study was 6.6 (1 to 25.7) years. 16 patients with deviated musculature (49%) and 16 with short segment fibromuscular stenosis (50%) underwent operation for subaortic stenosis. Patients with deviated structures were younger at operation than those with short segment stenosis (P < 0.005). Patients with posterior deviation or extension of structures into the left ventricular outflow tract underwent operation for subaortic stenosis more frequently (P < 0.05) than those with anterior deviation of the outlet septum and aortic override. The ventricular septal defect required surgical closure more frequently (P < 0.005) in patients with deviation (93.9%) than in those with short segment obstruction (21.9%). There was no significant difference in the mortality between patients with deviation (27%) and those with short segment obstruction (12%). CONCLUSIONS--32% of patients in the clinical study with subaortic stenosis had a ventricular septal defect. Only 51% of these had obstructive and deviated muscular structures in the left ventricular outflow tract. These patients had a significantly higher incidence of aortic arch obstruction and required surgery for subaortic stenosis at a younger age than those with short segment obstruction. The ventricular septal defect also required surgical closure more frequently in those patients with deviation. The morphological study defined the two sites of obstruction. The presence or absence and type of deviation should be clearly defined in all patients with a ventricular septal defect,     

Severe dynamic obstruction of the left ventricular outflow tract induced by dobutamine

We present the case of a 63-year-old man who developed a subaortic gradient of 182 mmHg during an echocardiographic pharmacological stress study with dobutamine.     

Liwen术式治疗轻度室间隔肥厚伴左室流出道严重梗阻并随访2年一例

对优化药物治疗后效果不佳的梗阻性肥厚型心肌病,采用课题组的创新术式经皮超声引导下室间隔心肌内射频消融术(即Liwen术式),成功地治疗了 1例室间隔轻度肥厚但伴有严重左室流出道狭窄的肥厚型心肌病患者.患者术后恢复良好,无左心室流出道梗阻或心律失常.     

Isolated hypertrophy of the basal ventricular septum: Characteristics of patients with and without outflow tract obstruction

Background

Isolated basal septal hypertrophy (IBSH) of the left ventricle (LV) is not a well understood phenomenon, particularly in the presence of concomitant left ventricular outflow tract obstruction (LVOTO). We evaluated the prevalence of IBSH and compared those with and without LVOTO.

Methods

Retrospective observational study of 4104 consecutive patients undergoing echocardiography at a community cardiology practice and a hospital without specialized Hypertrophic Cardiomyopathy (HCM) service to determine prevalence of IBSH, defined as isolated hypertrophy (> 15 mm) of the basal LV septum (BS) without hypertrophy elsewhere. Clinical, ECG and echocardiographic characteristics were compared in IBSH with and without LVOTO.

Results

Prevalence of IBSH was 5.8% (240/4104): mean (SD) age was 76.0y (10.4) with equal gender distribution. Prevalence increased with age (p < 0.001 for trend), reaching 7.8% over 70y. None had a family history of HCM, and HCM-associated ECG changes were uncommon. Mean BS thickness (SD) was 17.8 mm (0.24) with a BS/posterior wall ratio (SD) of 1.76 (0.31). Resting peak LVOT gradient (> 20 mm Hg) was present in 8/240 (3.3%), mean (SD) 69.6mm Hg (59.3). Patients with LVOTO had hypercontractile LV function (fractional shortening [SD] 51.8% [9.5] vs. 40.5% [10.9], p = 0.012) compared to those without LVOTO, but had similar BS thickness [SD] (17.8 mm [3.0] vs. 17.8 mm [2.8], p = 0.996) and ECG characteristics. Greater apical and septal displacements of the mitral valve co-aptation point characterized those with IBSH and LVOTO.

Conclusions

IBSH is common in elderly patients referred for echocardiography. LVOTO occurs only when concomitant mitral valve co-aptation and LV hypercontractility facilitate development of a gradient, rather than through differences in the degree of BS myocardial hypertrophy.     

Echocardiographic left ventricular geometry in hypertensive patients with electrocardiographic left ventricular hypertrophy: The LIFE Study

Aim: To assess the prevalence of echocardiographic left ventricular hypertrophy (LVH) and concentric remodeling in hypertensive patients with electrocardiographic (ECG)-LVH and to estimate the costeffectiveness of echocardiography and ECG for detection of LVH.Design: Echocardiographic LV measurements and the prevalence of abnormal LV geometric patterns were compared between 964 hypertensive patients with ECG-LVH (Cornell voltage-duration product > 2440 and/or SV₁     

The evaluation of left ventricular hypertrophy in hypertensive patients with subclinical hyperthyroidism

The aim of this prospective cross-sectional study was to investigate the hypertrophic effects of endogenous subclinical hyperthyroidism on myocardium and early development of left ventricular hypertrophy (LVH) in essential hypertensive patients accompanied by endogenous subclinical hyperthyroidism. A total of 31 consecutive patients with stage I hypertension were included in the study. Sixteen of them also had endogenous subclinical hyperthyroidism that they were unaware before. The patients and the controls formed out of ten healthy subjects all underwent an investigation of thyroid functions and cardiologic evaluation. The mean wall thickness of the left ventricle in the stage I hypertensive group with endogenous subclinical hyperthyroidism (group I) was significantly increased as compared with both hypertensive patients without thyroid disease (group II) and the control subjects. The mean left ventricle mass was also significantly higher in group I than group II. Both of the patients' groups had an increased prevalence of LVH as compared with the controls. In this study, hypertensive patients with subclinical hyperthyroidism presented more increase in left ventricular mass, suggesting that subclinical hyperthyroidism may contribute to left ventricular hypertrophy forming a natural progression to hypertension. The hypertensive population should always be screened for endogenous subclinical hyperthyroidism, and should be examined for the criteria of left ventricular hypertrophy by echocardiography in early stages.