Gender differences in postinfarction left ventricular remodeling.

OBJECTIVE: Previous studies suggest that gender affects the adaptive responses of the heart to some forms of cardiac overload. It is unknown whether gender influences left ventricular (LV) remodeling after myocardial infarction (MI). METHODS: We performed transthoracic echocardiographic-Doppler examinations in age-matched male (n = 17) and female (n = 16) rats before, and 1 and 6 weeks after transmural MI or sham surgery. RESULTS: Following large MI (male = 45 +/- 1% LV circumference vs. female = 48 +/- 4%, p = NS), both male and female rats developed progressive LV dilatation. Infarctions caused a similar degree of global and regional LV systolic dysfunction in males and females. Male rats had significant increases in the thickness of the noninfarcted posterior wall by 6 weeks after MI. However, posterior wall thickness did not change in the infarcted female rats. Average myocyte diameter in the noninfarcted region of the heart was also greater in male than female MI rats. The combination of increased cavity size with little change in wall thickness resulted in a greater decline in relative wall thickness in the female rats compared to the males. Male rats with MI showed progressively restricted LV diastolic filling as assessed by transmitral Doppler recordings. Female rats had less of an increase in the ratio of early to late transmitral velocities and less of an increase in the E wave deceleration rate after MI. CONCLUSIONS: Female rats showed a different pattern of LV remodeling than males with less of an increase in thickness of the noninfarcted portions of the left ventricle than males, but comparable LV cavity enlargement and systolic dysfunction. Despite similar infarct size, females developed less pronounced abnormalities of LV diastolic filling. We hypothesize that the gender-related differences in postinfarction LV remodeling may contribute to the different LV filling patterns, and might ultimately relate to differences in clinical outcome.     

Abnormal left ventricular torsion and cardiac autonomic dysfunction in subjects with type 1 diabetes mellitus

Left ventricular torsion is increased and cardiac energetics are reduced in uncomplicated type 1 diabetes mellitus (T1DM). Our aim was to determine the relationships of these abnormalities to cardiovascular autonomic neuropathy (CAN) in subjects with T1DM. A cross-sectional study was conducted in 20 subjects with T1DM free of known coronary heart disease attending an outpatient clinic. Cardiovascular autonomic neuropathy was assessed using heart rate variability studies and the continuous wavelet transform method. Left ventricular function was determined by speckle tracking echocardiography. Magnetic resonance spectroscopy and stress magnetic resonance imaging were used to measure cardiac energetics and myocardial perfusion reserve index, respectively. Twenty subjects (age, 35 ± 8 years; diabetes duration, 16 ± 9 years; hemoglobin A_1c, 8.0% ± 1.1%) were recruited. Forty percent of the subjects exhibited definite or borderline CAN. Log peak radial strain was significantly increased in subjects with CAN compared with those without (1.56 ± 0.06 vs 1.43 ± 0.14, respectively; P = .011). Data were adjusted for log duration of diabetes, and log left ventricular torsion correlated (r = 0.593, P = .01) with log low-frequency to high-frequency ratio during the Valsalva maneuver. Log isovolumic relaxation time correlated significantly with log Valsalva ratio and log proportion of differences in consecutive RR intervals of normal beats greater than 50 milliseconds during deep breathing. However, CAN did not correlate with cardiac energetics or myocardial perfusion reserve index. Spectral analysis of low-frequency to high-frequency ratio power during the Valsalva maneuver is associated with altered left ventricular torsion in subjects with T1DM. Parasympathetic dysfunction is closely associated with diastolic deficits. Cardiovascular autonomic neuropathy is not however the principal cause of impaired cardiac energetics. The role of CAN in the development of cardiomyopathy warrants further evaluation.     

QT variability strongly predicts sudden cardiac death in asymptomatic subjects with mild or moderate left ventricular systolic dysfunction: a prospective study.

AIMS: The most widely accepted marker for stratifying the risk of sudden cardiac death (SCD) in post myocardial infarction patients is a depressed left ventricular function. Left ventricular ejection fractions (EF) of 35% or less increase the risk of sudden death but values between 35 and 40% raise concern. The underlying pathophysiological mechanism is sustained ventricular tachycardia or fibrillation, both associated with increased cardiac repolarization variability. We assessed whether the indices of QT variability from a short-term electrocardiographic (ECG) recording predict sudden death. METHODS AND RESULTS: A total of 396 subjects with chronic heart failure (CHF) due to post-ischaemic cardiomyopathy, with an EF between 35 and 40% and in NYHA class I, underwent a 5 min ECG recording to calculate the following variables: QT variance (QT(v)), QT normalized for the square of the mean QT (QTVN), and QT variability index (QTVI). Corrected QT (QT(c)) was calculated from a 12-lead ECG recording. All participants were followed for 5 years. A multivariable survival model indicated that a QTVI greater than or equal to the 80th percentile indicated a high risk of SCD [hazards ratio (HR) 4.6, 95% confidence interval (CI) 1.5-13.4, P = 0.006] and, though to a lesser extent, a high risk of total mortality (HR 2.4, 95% CI 1.2-4.9, P = 0.017). The model including QTVI as a continuous variable confirmed a similar high risk for SCD (HR 2.9, 95% CI 1.3-6.5, P = 0.01) and for total mortality (HR 2.6, 95% CI 1.3-5.2, P = 0.008). CONCLUSION: Although asymptomatic patients with CHF who have a slightly depressed EF are at low risk of sudden death, the category is extraordinarily numerous. The QTVI could be helpful in stratifying the risk of sudden death in this otherwise undertreated population.     

Cardiovascular risk in subjects with left ventricular concentric remodeling at baseline examination: a meta-analysis

It is debated whether subjects with concentric remodeling (CR, normal left ventricular mass index (LVMI) and increased relative wall thickness (RWT)) are at higher cardiovascular risk than those with normal geometry (NG, normal LVMI and RWT). The aim of this study was to perform a meta-analysis of studies evaluating cardiovascular events in subjects with CR and NG according to baseline classification. We searched for articles evaluating cardiovascular outcome in subjects with CR compared with those with NG, and reporting adjusted hazard ratio (HR) and 95% confidence interval (CI). Six studies were included in the meta-analysis. The pooled population consisted of 7465 subjects with CR and NG. During the follow-up, they experienced 852 events. When compared with NG, the overall adjusted HR was 1.36 (95% CI 1.03-1.78) for CR, P<0.03. There was some heterogeneity between studies. Subgroup meta-analysis showed that increased cardiovascular risk in subjects with CR was more relevant in studies evaluating hypertensive and Caucasian subjects and reporting both fatal and non-fatal events. Cardiovascular risk is significantly higher in subjects with CR than in those with NG. This aspect is more evident in studies including hypertensive patients and Caucasian populations and reporting global cardiovascular risk.     

螺内酯对无症状左室收缩功能障碍患者心室重构的影响

目的:探讨螺内酯对无症状左室收缩功能障碍患者心室重构的影响.方法:入选我院2007-12-2009-06门诊及住院无症状左室收缩功能障碍[左室射血分数(LVEF)＜40%,左室舒张末期容积指数(LVEDVI)＞75 ml/m2,纽约心脏病协会心功能分级Ⅰ级]患者63例,在常规治疗的基础上随机分为螺内酯干预组32例(螺内酯40 mg/d),对照组31例,所有患者在入选前及药物应用6个月后行超声心动图检查评估LVEDVI、左室收缩末期容积指数(LVESVI)、左室质量指数(LVMI)和LVEF的变化.结果:治疗6个月后,2组LVEDVI、LVESVI、 LVMI和 LVEF均较治疗前有明显改善,且差异有统计学意义(均P<0.05),螺内酯组改善更为显著(均P<0.05).结论:在常规治疗的基础上加用螺内酯治疗可进一步改善无症状左室收缩功能障碍患者的心室重构.     

Diastolic dysfunction and left atrial volume: a population-based study

OBJECTIVES: We examined the association between diastolic function and left atrial volume indexed to body surface area (LAVi) in a population-based study. BACKGROUND: Atrial enlargement has been suggested as a marker of the severity and duration of diastolic dysfunction (DD). However, the association between DD and atrial enlargement and their individual prognostic implications in the population is poorly defined. METHODS: A cross-sectional sample of Olmsted County, Minnesota, residents > or =45 years of age (n=2,042) underwent comprehensive Doppler echocardiography and medical record review. RESULTS: The LAVi increased with worsening DD: 23 +/- 6 ml/m2 (normal), 25 +/- 8 ml/m2 (grade I DD), 31 +/- 8 ml/m2 (grade II DD), 48 +/- 12 ml/m2 (grades III to IV DD). In bivariate analyses, age, left ventricular mass index, and DD grade were positively associated, whereas female gender and ejection fraction (EF) were inversely associated with LAVi (p <0.001 for all). When controlling for age, gender, cardiovascular (CV) disease, EF, and left ventricular mass, grade II DD was associated with a 24%, and grade III to IV DD was associated with a 62% larger LA volume (p <0.0001 for both). The area under the receiver-operator characteristic curve for LAVi to detect grade I, grade II, or grade III to IV DD was 0.57, 0.81, and 0.98, respectively. Both DD and LAVi were predictive of all-cause mortality, but when controlling for DD, LAVi was not an independent predictor of mortality. CONCLUSIONS: These data suggest that DD contributes to LA remodeling. Indeed, DD is a stronger predictor of mortality; presumably it better reflects the impact of CV disease within the general population.     

Association of left atrial myocardial function with left ventricular diastolic dysfunction in subjects with preserved systolic function: a strain rate imaging study

Background:

The purpose of this study was to investigate the relationship between left atrial (LA) myocardial function and left ventricular (LV) diastolic dysfunction in subjects with preserved LV ejection fraction (LVEF).

Methods:

The study included a group of 118 hypertensive patients and normal subjects. LV diastolic dysfunction was classified into 4 groups: none, mild, moderate, and severe. Peak strain rates in systole (S‐Sr), early diastole (E‐Sr), and late diastole (A‐Sr) were obtained from Doppler‐derived strain rate imaging to evaluate LA myocardial deformation.

Results:

No significant difference in LA dimension was observed in subjects with different degrees of LV diastolic dysfunction, although LA myocardial strain rate parameters were all significantly different across the 4 groups (all with P < 0.001). Compared with patients of normal diastolic function, the mild diastolic dysfunction group had significantly lower E‐Sr (0.62 ± 0.18 s^?1 vs 1.20 ± 0.38 s^?1, P < 0.001) and S‐Sr (0.78 ± 0.16 s^?1 vs 0.94 ± 0.22 s^?1, P < 0.001) but increased A‐Sr (1.14 ± 0.29 s^?1 vs 1.00 ± 0.23 s^?1, P = 0.05).

Conclusions:

By using strain rate imaging, significant changes of LA deformation in response to different stages of LV diastolic dysfunction were detected in subjects with preserved LVEF. Quantification of LA myocardial function rather than LA size may have the potential to predict early LV diastolic dysfunction in subjects with preserved LVEF. Copyright © 2010 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.

     

Ventricular remodeling in children with left ventricular dysfunction secondary to various cardiomyopathies

The ventricular remodeling that occurs in adults with left ventricular (LV) dysfunction is characterized by a change in LV shape from an ellipse to more of a sphere and is associated with increased functional mitral regurgitation (MR), decreased exercise tolerance, and poor outcome. There are limited data on the occurrence and importance of LV remodeling in children with LV dysfunction. The purposes of this study were to evaluate in children with LV dysfunction (1) LV shape, (2) changes in LV shape as LV function improves, and (3) the relation between LV shape and functional MR. Children with LV dysfunction were identified and compared with controls. Patient demographics, treatment, and outcomes were noted. Echocardiograms were reviewed for LV function and shape (sphericity index). The echos of a subset of children whose LV ejection fractions (LVEFs) increased by >10% over a follow-up of >6 months were analyzed for changes in sphericity, mitral annulus size, and the degree of MR. Twenty-five children with LV dysfunction were compared with 37 age-matched controls. LV remodeling to a more spherical shape was inversely related to LVEF but was not associated with clinical outcome. In a subset of patients (n = 17) whose LVEFs improved, the reversal of remodeling (decrease in sphericity index) was associated with a decrease in MR and mitral annulus size. In conclusion, LV remodeling occurs in children with LV dysfunction. The reversal of this remodeling with a decrease in the degree of MR and the size of the mitral annulus occurs as systolic function improves.     

Effect of revascularization on left ventricular remodeling in patients with heart failure from severe chronic ischemic left ventricular dysfunction

Few data exist regarding the effect of revascularization on left ventricular (LV) geometry in patients with severe LV systolic dysfunction and viable myocardium. We hypothesized that patients with chronic ischemic LV dysfunction but viable myocardium will have improved LV geometry after revascularization, which in turn will improve long-term outcome. Accordingly, 70 patients with severe ischemic LV dysfunction (LV ejection fraction <0.35) were studied at rest. They then either underwent revascularization (n = 36) or were treated medically (n = 34). Fifty-four patients had viable myocardium, and 16 did not. They were evaluated for change in LV function and geometry (size and shape) a mean of 21 months later. Further follow-up was performed for a mean of 3.5 years to determine outcome. Patients with viable myocardium had improvement not only in regional and global function, but also in LV geometry (shape and size), which was independent of and incremental to the improvement in function. On long-term follow-up, change in LV end-systolic volume was the only multivariate discriminator between 15 patients who died and 55 who did not, irrespective of whether they had undergone revascularization. Thus, measurement of the effect of revascularization of viable myocardium in chronic ischemic heart disease should not only include improvement in resting regional and global LV function, but also LV geometry. Improvement in LV geometry contributes to better LV systolic function, which in turn is the best predictor of survival after revascularization.     

Prevalence of asymptomatic left ventricular systolic dysfunction in hypertensive Nigerians: echocardiographic study of 832 subjects

Background

We sought to determine the prevalence of echocardiographically determined left ventricular systolic dysfunction in asymptomatic hypertensive subjects seen in Abeokuta, Nigeria.

Methods

Echocardiography was performed in 832 consecutive hypertensive subjects referred for cardiac evaluation over a three-year period.

Results

Data were obtained in 832 subjects (50.1% women) aged 56.0 ± 12.7 years (men 56.9 ± 13.3 years, women 55.0 ± 12.0 years, range 15–88). The prevalence of left ventricular systolic dysfunction (LVSD) was 18.1% in the study population (mild LVSD = 9.6%, moderate LVSD = 3.7% and severe LVSD = 4.8%). In a multivariate analysis, male gender, body mass index and LV mass were the predictors of LVSD.

Conclusion

Significant numbers of hypertensive subjects in this study had varying degrees of left ventricular systolic dysfunction. Early introduction of disease-modifying drugs in these patients, such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers may retard or prevent the progression to overt heart failure.     

代谢综合征患者血管内皮功能与左心室重构关系

目的探讨代谢综合征(MS)患者血管内皮功能与左心室重构情况及两者的相关性。方法选择43名健康人为对照组,92例MS患者分为3组:肥胖及血脂紊乱合并原发性高血压而血糖正常组(MS1组);合并2型糖尿病血压正常组(MS2组);合并原发性高血压和2型糖尿病组(MS3)。使用彩色超声多普勒分别测量血管内皮功能及左心室结构相关参数,分析两者的相关性。结果MS1、MS2、MS3组内皮依赖性血管舒张功能(EDD)较对照组明显降低(P<0.01);MS3组EDD障碍较MS1、MS2组更明显(P<0.05)。MS1、MS2、MS3组舒张末期室间隔厚度、舒张末期左心室后壁厚度、左心室质量、左心室质量指数(LVMI)均明显高于对照组(P<0.05或P<0.01);并且MS2、MS1、MS3的各参数值分别依次增加,3组间差异有统计学意义(P<0.05或P<0.01)。EDD与LVMI呈负相关(偏相关系数为-0.306,P<0.05)。结论MS的危险因素与血管内皮功能紊乱和左心室重构相关。血管内皮功能紊乱与左心室重构有关。     

Recent insights into cardiac hypertrophy and left ventricular remodeling

Cardiac hypertrophy is a compensatory mechanism of the heart to maintain cardiac output under stresses that compromise cardiac function. Mechanical stretch and neurohumoral factors induce changes in intracellular signaling pathways resulting in increased protein synthesis and activation of specific genes promoting cardiac growth, eventually leading to left ventricular remodeling and cardiac dysfunction. The remodeling process results from alterations in cardiac myocytes as well as the extracellular matrix.     

Gender differences in electrical remodeling and susceptibility to ventricular arrhythmias in rabbits with left ventricular hypertrophy

BACKGROUND: Left ventricular hypertrophy (LVH) is associated with an increased risk of death, vulnerability to ventricular arrhythmia, and multiple electrophysiological abnormalities. OBJECTIVES: The purpose of the present study was to determine the gender-dependent differences in electrical remodeling and the susceptibility to ventricular arrhythmias in a rabbit model of renovascular hypertension. METHODS: Rabbits of both sexes underwent unilateral renal artery banding and contralateral nephrectomy or were placed in the control group. Data are expressed as mean +/- standard error of the mean. RESULTS: The duration of action potentials was prolonged in the LVH group compared with the control group in both male (123 +/- 2.4 ms and 151 +/- 2.3 ms vs. 180 +/- 5.1 ms and 196 +/- 3.1 ms for action potential duration [APD](90 Epi) and APD(90 Endo) of control [n = 5] and LVH rabbits [n = 8], respectively; P<.05) and female rabbits (131 +/- 1.9 ms and 166 +/- 2.0 ms vs. 156 +/- 4.2 ms and 175 +/- 2.2 ms for APD(90 Epi) and APD(90 Endo) of control [n = 5] and LVH rabbits [n = 7], respectively; P<.05). Moreover, the gender-dependent differences in repolarization were opposite to those seen under control conditions. In LVH rabbits, APD(90) was greater in males than in females. The changes induced in APD lead to a greater transmural dispersion of repolarization (38 +/- 6.6 ms vs. 19 +/- 6.5 ms for males and females, respectively; P<.05). In addition, while control rabbits did not show induction of arrhythmias, an enhanced susceptibility to ventricular arrhythmia was seen in LVH male rabbits (6/8 male vs. 1/7 female LVH rabbits; P<.05). CONCLUSION: We conclude that the electrical remodeling associated with LVH inverted the gender-dependent differences, with male rabbits now exhibiting action potentials with longer durations both in the endocardial and epicardial surface of the left ventricle, increased dispersion of repolarization, and increased vulnerability to ventricular arrhythmia induction.     

糖尿病早期肾损害对左室重塑的影响

目的：探讨糖尿病早期肾功能损害对左室重塑的影响。方法：124例糖尿病患者根据尿微量白蛋白水平分别分为肾功能正常组（n=68）和早期肾功能损害组（n=56），比较左室结构的变化和左室肥厚的发生率。结果：早期肾功能损害组的左室后壁厚度（LVPWT）、左室质量（LVM）和左室质量指数（LVMI）较肾功能正常组明显增加，其数值分别为（9．0±1．2）mm：（8．3±1．0）mm、（159±2）g：（11±5）g和（43±2）：（30±1），P均〈0．05。早期肾功损害组左室肥厚（LVH）的发生率为21．9％，显著高于肾功能正常组的（2．3％），P〈0．05。结论：糖尿病早期肾功能损害对左室重构有显著影响，对糖尿病患者积极预防早期肾功能损害能减少左室重构的发生。     

抗心肌纤维化治疗家兔慢性心力衰竭的实验研究

目的 探讨姜黄素的抗心肌纤维化作用对家兔慢性心力衰竭(心衰)的影响.方法 30只新西兰大耳白兔随机分为对照组、心衰组、姜黄素组,每组10只.心衰组和姜黄素组采用主动脉瓣反流及主动脉缩窄法制作心衰模型,对照组做假手术但不造成主动脉瓣反流和主动脉缩窄.姜黄素组口服姜黄素(100 nag·kg-1·d-1),对照组和心衰组口服安慰剂.主动脉瓣反流术及其假手术前,主动脉缩窄术及其假手术后8周,所有动物做2次心脏超声检查.第2次超声检查后,取出心脏行基质金属蛋白酶(MMP)-2和MMP-9的免疫组织化学染色和Masson染色,观察MMP表达的改变和心肌纤维化情况.结果 前后2次超声结果 比较,心衰组左室射血分数和左室内径缩短分数显著下降,左室内径、左室后壁和室间隔厚度显著增大;姜黄素组上述指标也有显著改变,但程度较心衰组轻;对照组上述指标无显著改变.Masson染色显示,心衰组胶原含量高于姜黄素组和对照组(P<0.05);免疫组织化学染色显示,心衰组MMP-2和MMP-9的表达低于姜黄素组和对照组(P<0.05).结论 姜黄素通过提高MMP的表达可减轻心衰时的心肌纤维化,该作用可能是其改善心衰时心肌重构和心脏收缩功能的重要机制之一.抗纤维化治疗有可能成为心衰治疗的新方法 .     

Clinical significance of left ventricular reverse remodeling after catheter ablation of atrial fibrillation in patients with left ventricular systolic dysfunction

BackgroundLeft ventricular (LV) reverse remodeling (LVRR) after catheter ablation of atrial fibrillation (AFCA) has not been fully described. This study investigated the predictors and clinical outcomes of LVRR after AFCA in patients with LV systolic dysfunction.MethodsOf 3319 consecutive patients who underwent first-time AFCA between January 2012 and October 2019, 376 with a baseline LV ejection fraction of <50% were retrospectively evaluated. They were subjected to 256-slice multidetector computed tomography (MDCT) scanning at baseline and 3 months after AFCA. The LVRR was defined as a decrease in the LV end-systolic volume of ≥15%.ResultsThe prevalence of LVRR was 83% (n = 306). Multivariate logistic regression analysis including age, body mass index, diabetic status, beta-blocker use, and LV diastolic diameter revealed that the predictors of LVRR were non-paroxysmal atrial fibrillation (AF) (odds ratio, 2.68; 95% confidence interval, 1.42–5.05; p = 0.002) and absence of apparent underlying structural heart disease (4.81; 2.31–10.0; p <0.001). The prevalence of LVRR differed depending on AF recurrence pattern prior to the post-MDCT [no episode vs. paroxysmal episode (lasting <7 days) vs. persistent episode (lasting ≥7 days), 84% vs. 81% vs. 63%, respectively, p = 0.023]. During a median follow-up of 32 months, the incidence of paroxysmal form of AF recurrence was similar, whereas persistent form of AF recurrence was less frequent in patients with LVRR (10.5% vs. 18.6%, p = 0.018). Heart failure hospitalizations (2.3% vs. 15.7%, p <0.001), cardiovascular deaths (0.7% vs. 4.3%, p = 0.015), and all-cause deaths (1.3% vs. 5.7%, p = 0.018) were similarly less frequent in those with LVRR.ConclusionsLVRR after AFCA, which was predicted by non-paroxysmal AF without any apparent structural heart disease at baseline, was associated with persistent form of AF recurrence prior to the evaluation. LVRR was associated with favorable clinical outcomes.