Effectiveness of Cardiac Resynchronization Therapy in Diabetic Patients with Ischemic and Nonischemic Cardiomyopathy

Background: Diabetes mellitus (DM) increases the risk for the development of both ischemic and nonischemic cardiomyopathy. We aimed to identify differences in response to cardiac resynchronization therapy with a defibrillator (CRT‐D) among DM patients with ischemic or nonischemic cardiomyopathy. Methods: Cox proportional hazards regression modeling was used to assess clinical response to CRT‐D (defined as CRT‐D vs. defibrillator‐only reduction in the risk of heart failure [HF] or death) and echocardiographic response (defined as percent reduction in left ventricular end diastolic and systolic volume [LVEDV and LVESV, respectively] at 12 month of follow‐up compared with baseline values) among 552 diabetic patients with ischemic (n = 367) or nonischemic (n = 185) cardiomyopathy enrolled in MADIT‐CRT. Results: The clinical benefit of CRT‐D was more pronounced among nonischemic patients (HR = 0.30 [P < 0.001] than among ischemic patients (HR = 0.59 [P = 0.004]; P for interaction = 0.10). Nonischemic patients also experienced significantly greater reductions in LVESV and LVEDV at 12 months with CRT‐D compared with ischemic patients (P < 0.001 for both). Subgroup analysis showed that the most pronounced reduction in HF or death with CRT‐D therapy occurred in nonischemic patients who were women (83% risk‐reduction [P < 0.001]), had a lower BMI (<30/kg/m²: 79% risk‐reduction [P < 0.001]), or had left bundle branch block at enrollment (82% risk‐reduction [P < 0.001]). Conclusions: The present study shows that treatment with CRT‐D in at‐risk cardiac patients with DM is associated with substantial reductions in the risk of HF or death and improvement in cardiac remodeling in those with ischemic and nonischemic cardiomyopathy, with a more pronounced benefit in patients with nonischemic disease. Ann Noninvasive Electrocardiol 2012;17(1):14–21     

Grading Functional Mitral Regurgitation by Tissue Doppler–Derived Isovolumic Acceleration Parameters in Patients with Nonischemic Dilated Cardiomyopathy

Functional mitral regurgitation (FMR) is relatively common in heart failure and it is associated with adverse prognosis. The severity of FMR is usually assessed by echocardiography. Tissue Doppler echocardiography is used to acquire signals to determine the myocardial systolic functional parameters, including systolic ejection velocity and the systolic isovolumic acceleration (IVAs) rate. We investigated the utility of isovolumic acceleration parameters to grade the severity of FMR in nonischemic dilated cardiomyopathy (DC) patients. We analyzed the left ventricular systolic IVA rate, systolic isovolumic contraction (IVCs) velocity, and IVA duration (IVAd) values in 73 patients with DC. Patients were subgrouped according to FMR grade (Group I = mitral regurgitation mild and moderate; Group II = mitral regurgitation severe). IVAs was similar between two groups; however IVCs and IVAd were significantly higher in Group II than Group I. The IVCs cutoff value to predict severe FMR was 1.2 cm/sec (sensitivity 75% and specificity 70%). The IVAd cutoff value to predict severe FMR was 33 ms (sensitivity 77% and specificity 77%). Patients with IVCs ≥ 1.2 cm/sec and IVAd ≥ 33 ms had significantly higher FMR volume than the other subgroups. IVCs and IVAd values are useful to determine FMR severity in patients with DC. (Echocardiography 2010;27:815‐822)     

Incidence and Clinical Significance of Ventricular Late Potentials in Idiopathic Dilated Cardiomyopathy Compared to Coronary Artery Disease

Objective: This prospective study was designed to compare incidence and clinical significance of ventricular late potentials between patients with idiopathic dilated cardiomyopathy (IDC) and postinfarct patients (CAD) using exactly the same method of signal-averaged electrocardiography (SAECG) in both patient groups. Methods: Time-domain analysis of SAECG was performed in 120 consecutive patients with IDC, 120 patients with CAD, and 60 healthy controls. Ventricular late potentials were detected in 27 of 120 patients with IDC (23%) compared to 41 of 120 patients with CAD (34%; P < 0.05). Results: Ventricular late potentials were found in 2 of 60 controls (3%). During 15 ± 7 months follow-up, serious arrhythmic events occurred in 17 of 120 patients with IDC (14%) and in 13 of 120 patients with CAD (11%). The sensitivity of ventricular late potentials for future arrhythmic events was 35% for IDC compared to 77% for CAD (P < 0.05). The positive predictive value of late potentials detected by time-domain analysis was 22% for IDC versus 24% for CAD (P = ns). Conclusion: In this selected patient population with IDC and CAD, time-domain analysis of SAECG revealed a lower incidence of ventricular ate potentials in patients with IDC as compared to postinfarct patients. Whereas ventricular late potentials had a high sensitivity but a low positive predictive value for identification of postinfarct patients with serious arrhythmic events during follow-up, both sensitivity and positive predictive value of ventricular late potentials for future serious arrhythmic events were low in the setting of IDC.     

The Mechanisms and Importance of Tricuspid Regurgitation and Hepatic Pulsations in Dilated Cardiomyopathy: A Review

Secondary tricuspid regurgitation is a common finding in dilated cardiomyopathy, being present in up to 90% of patients studied with Doppler echocardiography. It appears to be primarily due to annular dilatation and loss of the sphincter-like action of the tricuspid annulus during systole. Apical displacement of the papillary muscle and increased chordal tension may also contribute to mal-coaptation of the tricuspid leaflets in systole. Hepatic pulsations generally occur late in dilated cardiomyopathy, indicating hepatic congestion due to progressive biventricular failure. These are thought to result from secondary tricuspid regurgitation and transmission of the regurgitant v wave to the liver. Careful pulsed-Doppler studies of the timing of hepatic pulsations in dilated cardiomyopathy often show them to be presystolic, rather than systolic, suggesting that a mechanism other than tricuspid regurgitation may be responsible. (ECHOCARDIOGRAPHY, Volume 8, March 1991)     

扩张型心肌病的病因与治疗研究进展

扩张型心肌病（DCM）多呈散发、隐匿性发病,病因不明,缺乏特异性治疗方法,病死率较高,患者生活质量差,给社会造成巨大经济负担。因此,对DCM进行病因学和药物治疗研究具有重要意义。目前认为DCM的病因与感染、自身免疫、基因、遗传性因素和细胞凋亡等因素有关。临床治疗方面第3代β受体阻滞剂的问世显著降低了患者的病死率,免疫干预与免疫吸附已取得了显著的疗效;心脏再同步化治疗明显改善了患者的心功能,已成为患者的一项辅助治疗手段;心脏移植是终末期患者的有效治疗手段之一。基础研究方面基因治疗与细胞移植是目前研究的热点,有望为患者开创新的治疗途径。     

The Prevalence and Prognostic Effects of Subclinical Thyroid Dysfunction in Dilated Cardiomyopathy Patients: A Single-Center Cohort Study

BackgroundSubclinical thyroid dysfunction may be a risk factor for mortality in patients with heart failure and may be associated with dilated cardiomyopathy (DCM). This was a cohort study to examine the possible association between subclinical thyroid dysfunction and all-cause mortality in DCM patients, because the current evidence on this association remains elusive.Methods and ResultsA total of 963 DCM patients were evaluated for thyroid function. Of these patients, 7.1% (n = 68) had subclinical hyperthyroidism (defined as serum thyroid-stimulating hormone [TSH] <0.35 μIU/mL), 84.7% (n = 816) had euthyroidism (TSH 0.35-5.5 μIU/mL), and 8.2% (n = 79) had subclinical hypothyroidism (TSH >5.5 μIU/mL). There was a significant difference in all-cause mortality rates between patients with euthyroidism and patients with subclinical hyper- and hypothyroidism (21%, 38.2%, and 26.6%, respectively; log-rank χ² = 13.104; P = .001) with mean follow-up of 3.5 years. After adjustment for other confounding factors at baseline, QRS duration, N-terminal pro–B-type natriuretic peptide, New York Heart Association functional class, left atrial diameter, and subclinical hyperthyroidism (hazard ratio 1.793, 95% CI 1.010–3.183; P = .046) emerged as significant predictors of all-cause mortality.ConclusionDCM patients with subclinical hyper- and hypothyroidism had higher all-cause mortality rates. However, only subclinical hyperthyroidism, not subclinical hypothyroidism, was an independent predictor for increased risk of all-cause mortality.     

缺血性和非缺血性心肌病核素心肌断层显像的定量分析

本文回顾性地分析了24例缺血性心肌病（ISCM）和21例非缺血性心肌病（NISCM）患者的核素心肌断层显像与超声心动图，并且结合53例正常对照组心肌定量结果进行了定量分析，结果显示陈旧性心梗组（OMI）、高血压病组（EN）和扩张性心肌病组（DCM）的左室扩大，腔／壁比值分别是2、13±0．44、2．25±0．38及2．78±0．70与正常对照组的1．05±0．17比较有显著性差异（P＜0．01）。OMI组心肌定量分析见171个减低及缺损区。每个患者病变区数占自身总区数的11．60％～61．10％，平均27．16％，DCM组左室呈不均匀性分布，定量分析有27个减低区，每个患者病变心肌数占3．50％～11．52％，平均6．39％。两组分布存在显著性差异（P＜0．01）；EH组定量显像有52个增强区，每个患者心肌增强的区数占17．20％～50％，平均31．28％，DCM组有21个增强区，每个患者心肌增强的区数占0～10．72％，平均7．8％，两组分布有显著性差异（P＜0．01）。     

Noninvasive Assessment of Regional and Global Myocardial Contractility in Normal Control Subjects and in Patients with Dilated Cardiomyopathies

The aim of the present study was to develop a new noninvasive approach for the assessment of regional and global myocardial contractility without the need for pharmacological intervention to alter load. Thirty-four healthy adults and five adults with dilated cardiomyopathy (DCM) were studied. Patients with diabetes mellitus and hyperthyroidism were eliminated from the study. The remainder underwent echocardiography, sphygmomanometric blood pressure determination, and carotid pulse tracings. Left ventricular cross section in the parasternal long-axis four- and two-chamber views was divided into 20 segments. Associated measurements of end-systolic pressure and left ventricular ejection time enabled shortening, shortening rate, and ejection fraction / afterload relationships to be determined. A discriminant analysis showed that the ejection fraction / afterload relationship in patients with DCM differed substantially from that of control subjects and was the most sensitive in this regard. Endocardial shortening, mid-wall shortening, and ejection fraction / afterload relationships demonstrated linearity or nonlinearity for control subjects. This study thus permits the assessment of contractility in individual subjects without the need for drug interventions because load alteration stems from the variation of wall stress from base to apex in the left ventricle. More importantly, the approach may be applied to patients with segmental abnormalities of contractile function.     

晋北地区原发性扩张型心肌病与血清元素的相关性研究

目的探讨晋北地区原发性扩张型心肌病与血清元素含量的关系。方法①对住院治疗的296例原发性扩张型心肌病病人进行性别、发病年龄、县域分布的回顾性分析;②采用多通道智能型火焰原子吸收光谱仪,对晋北地区部分区县人群血清元素Cu,Zn,Fe,Ca,Mg,Se抽样调查;③将87例原发性扩张型心肌病病人与90名健康人血清Cu,Zn,Fe,Ca,Mg,Se水平进行比较。结果晋北地区原发性扩张型心肌病发病存在明显区域性,高发区人群血清Zn,Se,Mg含量低于其他区域;而患病人群的这3种血清元素较健康人群更低。结论晋北地区原发性扩张型心肌病发病与血清Zn,Se,Mg降低有关。     

C-reactive protein and aortic stiffness in patients with idiopathic dilated cardiomyopathy

BACKGROUND: Previous studies have shown an association between C-reactive protein (CRP)and arterial stiffness in most cardiovascular diseases. Increased CRP levels and arterial stiffness have been considered independent predictors of cardiovascular mortality in cardiovascular disease and even in the general population. OBJECTIVE: The aim of this study was to investigate the relationship between CRP, a marker of systemic inflammation and aortic stiffness in patients with idiopathic dilated cardiomyopathy (DCMP). METHODS: Serum CRP levels and aortic stiffness parameters were measured in DCMP patients (n= 37) and age- and gender-matched control subjects (n= 30). High-sensitivity CRP levels were determined by an immunonephelometry assay. Aortic strain (AS) and aortic distensibility (AD) were calculated from the aortic diameters measured using M-mode echocardiography and blood pressure obtained by sphygmomanometry. RESULTS: Serum levels of CRP in DCMP patients were higher than in the control subjects (5.47 +/- 2.06 mg/L and 2.35 +/- 0.47 mg/L, P < 0.001, respectively). AS and AD were significantly decreased in DCMP patients compared to the controls (P < 0.001 and P < 0.001, respectively). There were positive correlations between CRP, and (r = 0.3.64, P = 0.027) smoking (r = 0.3.56, P = 0.024), and increasing age (r = 0.587, P < 0.001), and negative correlations between CRP, and DBP (r =-0.485, P < 0.001), diameter change (DC; r =-0.493, P < 0.001), AS (r =-0.526, P < 0.001), and AD (r =-0.626, P < 0.001). CONCLUSION: We have shown that there is a significant relation between high serum CRP levels and impaired aortic stiffness in patients with idiopathic DCMP. These findings may indicate an important role of CRP in the pathogenesis of impaired aortic stiffness in idiopathic DCMP.