Left ventricular mechanics in dilated cardiomyopathy

The influence of altered chamber shape on the evaluation of left ventricular (LV) mechanics in idiopathic dilated cardiomyopathy (IDC) is unknown. Nine patients with IDC and 7 subjects with normal LV function were studied with simultaneous LV pressure and M-mode echographic recordings in order to derive LV meridional wall stress. The major axis of the left ventricle, determined from the left ventriculogram at rest, allowed for derivation of circumferential wall stress. The IDC group was characterized by larger end-diastolic and end-systolic LV volumes, increased LV mass, depressed angiographic ejection fraction and more spherical LV chamber shape. Both end-systolic meridional (114 +/- 30 kdyne/cm2) and circumferential (251 +/- 73 kdyne/cm2) wall stresses were elevated in patients with IDC, although the ratio of these stresses was less than normal (2.2 +/- 0.1 vs 2.7 +/- 0.2, respectively). LV load alteration with phenylephrine or nitroglycerin allowed for construction of end-systolic stress-minor-axis dimension and end-systolic stress-minor-axis shortening relations. Similar mean slopes of the meridional end-systolic stress-dimension relation were noted in IDC and normal subjects, although the line was displaced to the right in IDC. The slope of the circumferential end-systolic stress-dimension relation was, however, decreased in patients with IDC. Moreover, the end-systolic stress-fractional minor-axis shortening relation in patients with IDC was displaced downward from the normal relation supporting depressed contractile function in these IDC patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular systolic dysfunction in patients with obstructive sleep apnea syndrome

STUDY OBJECTIVES: Conflicting results have been reported regarding the effects of obstructive sleep apnea syndrome (OSAS) on daytime left ventricular (LV) systolic function. This study aimed to assess the prevalence and causes of LV systolic dysfunction, using radionuclide angiography, in a large group of patients with OSAS. DESIGN AND SETTING: A prospective study in the pneumology department of a university medical center. PATIENTS: One hundred sixty-nine consecutive patients with OSAS diagnosed by polysomnography, hospitalized for the administration of nasal continuous positive airway pressure. Patients with a known cardiac disease were excluded. MEASUREMENTS: LV ejection fraction (LVEF) was measured in all patients, using radionuclide ventriculography with multiple-gated equilibrium cardiac imaging. Myocardial scintigraphy with a dipyridamole stress test and echocardiography were performed in those patients with LV systolic dysfunction, defined by a LVEF < 50%, to detect silent heart disease, especially coronary artery disease. RESULTS: LV systolic dysfunction was observed in 7.7% (13 of 169 patients). In these 13 patients, the mean +/- SD LVEF was 42 +/- 6%, the lowest value of LVEF was 32%, and no silent cardiac disease was revealed. Age, body mass index, apnea-hypopnea index, parameters of nocturnal oxyhemoglobin desaturation, and prevalence of systemic hypertension did not significantly differ between patients with LVEF < 50% and those with LVEF > 50%. In seven patients with LV dysfunction, LVEF was measured following treatment of OSAS and reached normal values. CONCLUSION: OSAS may be a direct cause of daytime LV systolic dysfunction that can resolve following reversal of nocturnal apneas.     

阻塞性睡眠呼吸暂停综合征与扩张型心肌病

随着对阻塞睡眠呼吸暂停综合征(OSAS)认识的深入,OSAS与各类心血管疾病的相关性也逐渐得到重视。2009年中华医学会呼吸病学分会睡眠学组会同心血管病学会参照国外有关研究发表了《睡眠呼吸暂停与心血管疾病专家共识》,成为进一步促进、密切两个学科之间研究的新起点。文章对如何早期认识、诊断OSAS合并扩张型心肌病(DCM)做一简要介绍,强调DCM患者合并OSAS诊断的临床意义,分析CPAP治疗对DCM患者恢复心脏功能及心脏结构的临床价值。     

睡眠呼吸暂停低通气综合征与心房心肌病

睡眠呼吸暂停低通气综合征（OSA）与心血管疾病关系密切,与房颤等心房病变相关。心房心机病为近几年提出的新概念,评估方法有限。合理评估OSA患者心房功能,明确OSA与心房心机病的相关性,并积极探究OSA相关治疗与改善患者心房功能的关系,将有助于改善患者预后。     

阻塞性睡眠呼吸暂停低通气综合征与扩张性心肌病

阻塞性睡眠呼吸暂停低综合征（obstructive sleep apnea hypopnea syndrome,OSAHS）在睡眠呼吸障碍疾病中发病率最高,对人体健康和生命的危害最大。OSAHS是一种以睡眠过程中反复发生的上气道完全或不完全阻塞而导致频繁发生的呼吸暂停或低通气量为特征的睡眠呼吸障碍性疾病,其成年人患病率约为4％[1]。     

Left ventricular hypertrophy and abnormal ventricular geometry in children and adolescents with obstructive sleep apnea

Obstructive sleep apnea (OSA) has been shown to be an independent risk factor for cardiovascular disease in adults. However, there are severe limitations in the extent to which the cardiovascular consequences of OSA are being studied in children. To investigate the echocardiographic changes in children with OSA, right and left ventricular (RV, LV) dimensions and LV mass index and geometry were measured in 28 children with OSA and 19 children with primary snoring (PS). The study showed that LV mass index and relative wall thickness were greater in the OSA group compared with those with PS (p = 0.012 and p < 0.0001, respectively). An apnea-hypopnea index of more than 10 per hour was significantly associated with RV dimension above the 95th percentile (odds ratios, 6.7; 95% confidence interval, 1.4-32) and LV mass index above the 95th percentile (odds ratios, 11.2; confidence interval, 1.9-64). Abnormality of LV geometry was present in 15% of children with PS compared with 39% of children with OSA. We conclude that OSA in children is associated with increased LV mass.     

Left ventricular regional wall stress in dilated cardiomyopathy

Left ventriculography with simultaneous pressure micromanometry was performed in 11 normal control subjects and 17 patients with dilated cardiomyopathy (DCM). Left ventricular silhouettes in the right anterior oblique projection were divided into eight areas, and regional wall stress was computed by Janz's method in each area excluding the two most basal areas. Wall stress was higher in DCM patients than in control subjects (p less than 0.01). The percent area changes from end diastole to end systole in each area were lower in DCM patients than in control subjects (mean for six areas, 22 +/- 14% versus 54 +/- 9%, respectively, p less than 0.01), but the coefficient of variation for the percent area changes in the six areas of the left ventricle in DCM patients was greater than that in control subjects (32 +/- 17% versus 15 +/- 4%, respectively, p less than 0.01), indicating regional differences in hypokinesis. There was a significant negative correlation between end-systolic regional wall stress and percent area change (r = -0.60 to -0.86, p less than 0.05) in each area. Thus, excessive regional afterload may play an important role in causing regional hypokinesis in DCM.     

Left ventricular versus biventricular dysfunction in idiopathic dilated cardiomyopathy

Eighty-five consecutive patients with idiopathic dilated cardiomyopathy were categorized according to the presence (biventricular dysfunction) or absence (left ventricular [LV] dysfunction) of reduced right ventricular ejection fraction (<35%) along with reduced LV ejection fraction (<50%). Compared with the 36 patients with LV dysfunction, the 49 patients with biventricular dysfunction had significantly worse New York Heart Association functional class (2.7+/-0.6 vs 1.9+/-0.5; p <0.001), LV ejection fraction (26+/-10% vs 34+/-8%; p <0.0001), and outcome (transplant-free survival, 55% vs 89%; p <0.001). Thus, dilated cardiomyopathy is frequently characterized by biventricular involvement, which identifies a more severe disease and a worse long-term prognosis.     

Left ventricular geometry in patients with obstructive sleep apnea coexisting with treated systemic hypertension

BACKGROUND: Left ventricular (LV) hypertrophy is a common consequence of systemic hypertension (SH) and obstructive sleep apnea (OSA). However, little is known about the degree of LV involvement in patients with OSA coexisting with treated SH. OBJECTIVES: Our study was designed in order to assess the prevalence of distinct types of LV geometry in treated hypertensive OSA patients. METHODS: PATIENTS: 183 patients with treated SH were enrolled to the study. Group 1 consisted of 38 patients with newly-diagnosed OSA and ineffectively treated SH. The remaining 145 patients with effectively treated SH were divided into three groups: group 2 - 70 patients with newly-diagnosed OSA, group 3 - 31 patients with OSA treated with continuous positive airway pressure (CPAP), and group 4 - 44 patients without OSA.Overnight sleep studies and M-mode echocardiography were performed. RESULTS: LV mass index did not differ between the study groups. Mean values of LV end-diastolic diameter (LVED) were 55.4 +/- 6.8 mm in group 1 and 53.6 +/- 6.9 mm in group 2 and were significantly increased in comparison to subjects treated with CPAP and controls (49.8 +/- 6.8 mm and 50.1 +/- 64.7 mm, respectively; p = 0.001). LVED correlated positively with the apnea-hypopnea index and desaturation index. LV eccentric hypertrophy was the commonest type of LV geometry in newly-diagnosed OSA patients. CONCLUSIONS: The major finding of our study is the predominance of LV eccentric hypertrophy in newly-diagnosed OSA patients. We suggest that a relatively moderate degree of LV involvement in hypertensive OSA patients may depend on the cardioprotective effect of concomitant antihypertensive therapy, ameliorating OSA-dependent neurohumoral abnormalities.     

Cerebral structural changes in severe obstructive sleep apnea

Obstructive sleep apnea is associated with abnormalities in neuropsychologic function, and defects in respiratory control may contribute to pathogenesis. Abnormalities may be reflected in structural brain changes. Twenty-seven male untreated patients with severe sleep apnea without comorbidities, and 24 age-matched control subjects, had T1-weighted brain imaging in a high-resolution magnetic resonance scanner. Twenty-three patients with sleep apnea had repeat imaging after 6 months of continuous positive airways pressure treatment. No areas of gray matter volume change were found in patients using an optimized voxel-based morphometry technique, at p < 0.05 adjusted for multiple comparisons (despite the method being sensitive to changes in gray matter fraction of 0.17 or less in all voxels). Furthermore, no differences were seen in bilateral hippocampal, temporal lobe, or whole brain volumes, assessed by manual tracing of anatomical borders. No longitudinal changes were seen in gray matter density or regional volumes after treatment, but whole brain volume decreased slightly. We have found no gray matter volume deficits nor focal structural changes in severe obstructive sleep apnea. Whole brain volume decreases without focal changes after 6 months of continuous positive airways pressure treatment.     

Left ventricular diastolic function of patients with dilated cardiomyopathy

A study of 79 patients with dilatation cardiomyopathy (DCMP), making use of echo- and angiocardiography and catheterization of various heart compartments, has demonstrated considerable changes in left ventricular diastolic properties, common to this condition: reduced pliancy of heart chamber, increased myocardial rigidity and impaired myocardial relaxation. Reduced left ventricular diastolic pliancy is associated with myocardial hypertrophy and impaired relaxation.     

Left ventricular aneurysm in a patient with mildly dilated cardiomyopathy

We describe the case of a patient with mildly dilated idiopathic cardiomyopathy and left ventricular aneurysm, diagnosed in absence of a prior clinical history and anatomo-pathological features of myocardial infarction. To ascertain the diagnosis of idiopathic cardiomyopathy, the patient underwent cardiac catheterization with coronary angiography, that showed the lack of epicardial artery stenosis and a slow run-off of the contrast. An endomyocardial biopsy showed the presence of hypertrophic myocytes and interstitial fibrosis. Moreover, a thoracic high resolution computed tomography showed the features of pulmonary bilateral basal emphysema, interstitial thickening and bronchiectasis. Alfa1-anti-trypsin plasma levels were reduced. The patient, because of worsening of clinical and hemodynamic conditions, underwent at age of 36 a combined heart-lung transplantation. The pathological examination of the native organs confirmed the previous diagnosis. At the moment, this is the second report in the literature concerning the presence of left ventricular aneurysm in a patient with idiopathic cardiomyopathy without an underlying coronary artery disease or prior history of myocardial infarction.     

Left ventricular filling in dilated cardiomyopathy: relation to functional class and hemodynamics

Left ventricular systolic function does not correlate well with functional class in patients with dilated cardiomyopathy. To determine whether the correlation is better with Doppler indexes of left ventricular diastolic function, 34 patients with dilated cardiomyopathy (M-mode echocardiographic end-diastolic dimension greater than 60 mm, fractional shortening less than 25%, increased E point-septal separation) were studied. Patients were classified into two groups according to functional class. Group 1 consisted of 16 patients in New York Heart Association functional class I or II; group 2 included 18 patients in functional class III or IV. Left ventricular dimensions, fractional shortening, left ventricular mass, meridional end-systolic wall stress, peak early and late transmitral filling velocities and their ratio, isovolumetric relaxation period and time to peak filling rate were computed from pulsed wave Doppler and M-mode echocardiograms and calibrated carotid pulse tracings. Right heart catheterization was performed in 20 of 34 patients. No differences were observed between groups with regard to age, gender distribution, heart rate, blood pressure and M-mode echocardiographic-derived indexes of systolic function. Peak early filling velocity (72 +/- 13 versus 40 +/- 10 cm/s, p less than 0.001) was higher and atrial filling fraction (27 +/- 4% versus 46 +/- 8%, p less than 0.001) was lower in group 2 than in group 1. The ratio of early to late transmitral filling velocities was higher in group 2 patients (2.3 +/- 0.5 versus 0.7 +/- 0.2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular diastolic reserve during acute pressure loading in hypertrophic cardiomyopathy and dilated cardiomyopathy

To evaluate left ventricular diastolic reserve during acute pressure loading, changes in mitral flow velocity patterns before and after the elevation of blood pressure were analyzed by pulsed Doppler echocardiography in 11 cases of hypertrophic cardiomyopathy (HCM), nine cases of dilated cardiomyopathy (DCM), and 11 control subjects. Systolic blood pressure was elevated 25% above basal values by methoxamine infusion (0.01 mg/kg/min). Before and after methoxamine, left ventricular dimension and mitral flow velocity pattern were obtained by M-mode and pulsed Doppler echocardiography, respectively. The peak velocity in the rapid filling and atrial contraction phases and time-velocity integrals were measured from the flow pattern. After methoxamine, left ventricular diastolic dimension was significantly increased in all groups, from 43.8 +/- 4.7 mm to 47.4 +/- 4.9 mm in the control subjects, from 43.7 +/- 6.3 mm to 47.2 +/- 6.0 mm in HCM, and from 57.9 +/- 6.4 mm to 60.6 +/- 5.9 mm in DCM. Left ventricular systolic dimension was significantly increased from 48.6 +/- 8.4 mm to 52.8 +/- 8.3 mm in DCM, but not in the control subjects or HCM. The peak velocity in the rapid filling phase was significantly increased from 60 +/- 16 cm/sec to 69 +/- 14 cm/sec in the control subjects and tended to be increased from 44 +/- 13 cm/sec to 52 +/- 12 cm/sec in HCM. The extent of this increase tended to be less in HCM. However, the peak velocity in the rapid filling phase tended to decrease in DCM. There were no consistent trends of changes in the peak velocity in the atrial contraction phase in any groups. The mitral velocity integral increased from 502 Hz-sec to 621 Hz-sec in the controls and from 525 Hz-sec to 613 Hz-sec in HCM, but it did not increase in DCM. These findings suggest that there is impaired diastolic reserve during acute pressure loading in HCM and DCM and that the diastolic disturbance might be reflected in the early diastolic phase, rather than in the late diastolic phase.     

Left ventricular shape, afterload and survival in idiopathic dilated cardiomyopathy

Because idiopathic dilated cardiomyopathy is characterized by elevated wall stress and a more spherical left ventricle, the relations among shape, afterload and survival were examined. Thirty-six patients with cardiomyopathy were prospectively studied by two-dimensional echocardiography. Data included echocardiographic short- and long-axis cavity dimensions, their ratio and, with cuff systolic blood pressure, meridional and circumferential end-systolic stress and their ratios. Survivors (n = 16) were followed up for 52 months (range 40 to 76); nonsurvivors (n = 20) died an average of 11 months after study. Survivors had a smaller left ventricular end-diastolic short-axis dimension (6.4 versus 7.1 cm, p less than 0.03) but a similar long-axis length (8.6 versus 8.3 cm). However, overall cavity shape or the ratio of short- to long-axis end-diastolic dimensions was more spherical in those with poorer survival (ratio 0.76 versus 0.68, p less than 0.02). Meridional and circumferential end-systolic stresses were similar in the two groups, but stress was more evenly distributed in the long- and short-axis planes in nonsurvivors (meridional/circumferential stress ratio 0.57 versus 0.52 in survivors, p less than 0.05). Improved survival was associated with an end-diastolic short-axis dimension less than 7.63 cm, a short- to long-axis ratio less than 0.76 and a meridional to circumferential stress ratio less than 0.54. Life table analysis revealed a 28% mortality rate in patients with all three of these characteristics compared with 100% in patients with none. Survivors and nonsurvivors did not differ in systolic cavity dimension, wall thickness, relative wall thickness, cavity volume, percent posterior wall thickening or fractional shortening.(ABSTRACT TRUNCATED AT 250 WORDS)     

睡眠呼吸暂停低通气综合征问卷对阻塞性睡眠呼吸暂停综合征诊断价值

目的 评价阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的流行病学调查表筛查价值.方法 疑似OSAHS的987例患者为研究对象,按照中华医学会呼吸病学分会睡眠学组睡眠呼吸暂停低通气综合征流行病学调查表进行问卷并行多导睡眠监测.将此问卷表进行量化评分,用克隆巴赫信度系数(α系数)进行信度计算,将各相关因素做方差分析及x2检验,筛选出有统计学意义的因素最后做Logistic回归分析.以鼾声中度以上的打鼾及体质量指数≥25 kg/m2为高危,反之为低危,进行敏感性,特异性,假阳性,假阴性,阳性似然比,阴性似然比,阳性预测值等.结果 疑似OSAHS患者987例,其中男800例(81.05％),女187例(18.95％),年龄18～80岁,平均(47±12)岁,平均体质量指数(29±5) kg/m2.＞60岁者156例(15.81％),≤60岁者831例(84.19％).克隆巴赫信度系数(Cronbach'salpha)是0.803,假阳性者20,假阴性者142,真阳性者742,真阴性者83,问卷的敏感性是83.94％,特异性是80.58％,假阳性率19.42％,假阴性率16.06％,阳性似然比4.32,阴性似然比0.20,阳性预测值0.97,阴性预测值0.37,正确率83.59％.结论 该睡眠调查表对OSAHS筛查具有一定意义,可用于临床OSAHS的初筛,尤其适合在社区和基层医院中推广使用.