Pulmonary venous flow as assessed by Doppler echocardiography: potential clinical applications

During the past few years Doppler assessment of pulmonary venous flow has gained increasing interest. The growing experience with the use of transesophageal echocardiography, the approach that nearly always yields registrations adequate for quantitative analysis, has markedly contributed in this respect. The Doppler-derived pulmonary venous flow pattern can be regarded as a measure of left atrial inflow and it augments the clinical significance of Doppler transmitral flow in the evaluation of diastolic left ventricular function. This article summarizes physiological background, possible applications, and limitations of Doppler echocardiography of pulmonary venous flow in clinical cardiology.     

心肌梗死患者左室舒张功能评价方法的研究

探讨心肌梗死（ＭＩ）患者左室舒张功能的评价方法及临床应用。方法：采用脉冲多普勒超声心动 图技术检测５０例正常人和５０例ＭＩ患者的左房收缩时间间期（ＬＡＳＴＩ）。包括左房射血前期（ＡＰＥＰ）、校正心房射血 前期（ＡＰＥＰＣ）和左房射血期（ＡＥＴ）;肺静脉Ｓ峰、Ｄ峰、Ａ峰;二尖瓣血流Ｅ峰、Ａ峰及Ｅ／Ａ比值。ＭＩ组给予抗舒张 障碍治疗３周后再测量各项指标。结果：ＭＩ组的ＡＰＥＰ、ＡＰＥＰＣ缩短,ＡＥＴ延长;肺静脉Ｓ峰、Ａ峰增大,Ｄ峰减小; 二尖瓣Ｅ峰减小,Ａ峰增大（Ｐ＜０．０１）。ＭＩ组治疗３周后各项指标明显改善（Ｐ＜０．０１）。结论：综合多指标分析能 提高左室舒张功能评价的准确性。     

经食管超声心动图评估房颤栓塞危险性的临床研究

目的： 评价经食管超声心动图（ＴＥＥ） 在区分心房颤动（ 房颤） 栓塞高危人群中的应用价值。方法：８６例持续性房颤患者同时接受常规经胸超声心动图（ＴＴＥ） 和ＴＥＥ 检查,根据ＴＥＥ 探测到心房血栓的例数分为血栓阳性组和血栓阴性组,分别纪录以下各项指标：左房自发性超声对比现象（ＬＡＳＥＣ） 、左心耳（ＬＡＡ） 血流排空速率、ＬＡＡ 面积、左房内径、左室收缩功能参数、二尖瓣返流（ ＭＲ） 程度。结果：８６ 例中经ＴＥＥ 探测到２２ 例存在左房和／或左心耳血栓,而ＴＴＥ 仅探测到５ 人存在左房血栓（ Ｐ＜ ０ ．０００１） 。对血栓阳性和阴性组各项测值指标进行对比显示,ＬＡＳＥＣ 严重程度、ＬＡＡ 血流速率降低和ＬＡＡ 面积扩大在两组间存在极显著差异（ Ｐ＜ ０ ．０００１ 和０００１） 。ＬＡＡ面积扩大与ＬＡＳＥＣ 严重程度及ＬＡＡ 速率降低密切相关。结论： ＴＥＥ 探测心房血栓具有显著优势,并可测定与血栓形成密切相关的因素,在区分房颤栓塞高危人群方面具有重要价值     

食道心房调搏心负荷试验诊断冠心病的价值

目的探讨食道心房调搏心负荷试验（ＴＥＡＰ）诊断冠心病的价值,并与活动平板运动试验（ＴＭＥＴ）进行对比,同时对冠状动脉病变程度进行评估。方法自１９９３年５月～１９９７年１０月,８０例拟诊冠心病的住院病人同期行ＴＥＡＰ、ＴＭＥＴ及ＣＡＧ检查;以ＣＡＧ为诊断标准,确诊为ＣＨＤ者６０例,另２０例为ＣＡＧ正常者。ＣＡＧ均为右股动脉Ｓｅｌｄｉｎｇｅｒ法穿刺,ＪｕｄｋｉｎＳ法进行。ＴＥＡＰ、ＴＭＥＴ以心率达到次极限水平,二阶梯运动试验方法记录ＥＣＧ。结果ＴＥＡＰ诊断ＣＨＤ的敏感性、特异性为８１．６７％、９０％,并且与ＣＨＤ患者冠状动脉病变支数呈正相关。其与ＴＭＥＴ的敏感性、特异性相比更可靠（Ｐ＜０．０１）。结论食道心房调搏心负荷试验可以作为一种无创伤性、有效、简便的诊断ＣＨＤ的方法。并可对冠状动脉病变程度进行初略评估。     

单导管射频消融治疗频发房颤的预激综合征

采用单导管射频消融法治疗１２ 例预激综合征（ Ｗ Ｐ Ｗ） 。１２ 例中８ 例有反复快速性房颤史,３ 例须用同步直流电复律,１ 例伴有晕厥。旁路分别为左侧８ 条,右后间隔２ 条,右后侧及右前间隔各１ 条,右侧者有１ 例并存１ 条左侧隐匿旁路。全部旁路一次消融成功。术中未诱发房颤。随访５ ～１７ 月未见复发。     

Proceedings of the Symposium ‘Angiotensin AT1 Receptors: From Molecular Physiology to Therapeutics’: REGULATION OF RENAL TUBULAR SODIUM TRANSPORT BY ANGIOTENSIN II AND ATRIAL NATRIURETIC FACTOR

• 1 The effects of angiotensin II (AngII) on water and electrolyte transport are biphasic and dose-dependent, such that low concentrations (10^?12 to 10^?9 mol/L) stimulate reabsorption and high concentrations (10^?7 to 10^?6 mol/L) inhibit reabsorption. Similar dose-response relationships have been obtained for luminal and peritubular addition of AngII.
• 2 The cellular responses to AngII are mediated via AT₁ receptors coupled via G-regulatory proteins to several possible signal transduction pathways. These include the inhibition of adenylyl cyclase, activation of phospholipases A₂, C or D and Ca²⁺ release in response to inositol-1,4,5,-triphosphate or following Ca²⁺ channel opening induced by the arachidonic acid metabolite 5,6,-epoxy-eicosatrienoic acid. In the brush border membrane, transduction of the AngII signal involves phospholipase A₂, but does not require second messengers.
• 3 Angiotensin II affects transepithelial sodium transport by modulation of Na⁺/H⁺ exchange at the luminal membrane and Na⁺/HCO₃ cotransport, Na⁺/K⁺-ATPase activity and K⁺ conductance at the basolateral membrane.
• 4 Atrial natriuretic factor (ANF) does not appear to affect proximal tubular sodium transport directly, but acts via specific receptors on the basolateral and brush border membranes to raise intracellular cGMP levels and inhibit AngII-stimulated transport.
• 5 It is concluded that there is a receptor-mediated action of ANF on proximal tubule reabsorption acting via elevation of cGMP to inhibit AngII-stimulated sodium transport. This effect is exerted by peptides delivered at both luminal and peritubular sides of the epithelium and provides a basis for the modulation by ANF of proximal glomerulotubular balance. The evidence reviewed supports the concept that in the proximal tubule, AngII and ANF act antagonistically in their roles as regulators of extracellular fluid volume.

     

Atrial natriuretic peptide, sodium retention, and proteinuria in nephrotic syndrome

BACKGROUND.: Oedema formation in the nephrotic syndrome is primarily dueto tubular sodium retention. The pathogenetic role of alphaatrial natriuretic peptide (ANP), a hormonal promoter of natriuresisis unknown. METHODS.: In 31 patients (aged 35±11 years) with nephrotic syndromeand histopathological evidence of primary glomerulonephritis,we investigated plasma ANP concentration and its influence onrenal haemodynamics, natriuresis, and proteinuria (total protein,albumin, IgG excretion). Patients with a compensated treatedform of nephrotic syndrome due to primary glomerulonephritiswere included in the study. Serum creatinine levels were 1.4mg/dl. Diuretic medication was discontinued at least 24 h beforethe investigation was started. Patients were randomly assignedto ANP infusion (0.005 µg/kg*min; group II, n=15) or receivedplacebo (group III, n=16). Ten healthy subjects (group I) servedas normal controls. RESULTS.: In normal subjects (group I), ANP caused an increase in natriuresisfrom 14.5±4.2mmol/h to 26.4±11.1 mmol/h (P<0.01).In patients with nephrotic syndrome (group II), baseline sodiumexcretion of 10.5±6.0 mmol/h was increased to 19.6±14.8mmol/h with ANP infusion (P<0.01). No changes were seen inthe placebo group III. The absolute increase in ANP inducednatriuresis was not significantly different between group Iand II. However, plasma ANP levels were significantly higherin patients with nephrotic syndrome (166±87 pg/ml vs.74±21 pg/ml, P<0.05) and also reached higher levelsafter ANP infusion (P<0.01). Therefore, natriuresis was significantlyreduced when circulating ANP levels were taken into account(P<0.05). ANP administration resulted in an increase of totalprotein excretion in patients with the nephrotic syndrome (groupII, from 219±277 mg/h to 264±268 mg/h). Albuminelimination rose from 128±151 mg/h to 167±170mg/h (P<0.05) and IgG excretion from 4.91±6.67mg/hto 9.27±10.78mg/h (P<0.05). Healthy subjects alsoshowed a small but significant increase in albuminuria (48±38%,P<0.05). Low-dose ANP infusion did not, however, induce anysignificant alteration in GFR, ERPF and blood pressure. CONCLUSION.: ANP plasma concentrations in the steady state are elevated inpatients with the nephrotic syndrome. The natriuretic effectof ANP is reduced when referring to circulating ANP plasma levels.Elevated ANP levels enhance urinary protein excretion in thenephrotic syndrome. This is not due to modulation of GFR orFF, but is most probably attributable to increased glomerularpermeability.     

Left atrial thrombi in non-rheumatic atrial fibrillation: assessment of prevalence by transesophageal echocardiography

To determine the prevalence of left atrial thrombus in hospitalized patients with non-rheumatic atrial fibrillation, 48 patients were consecutively studied with single-plane transesophageal echocardiography. There were 23 males (48%) and 25 females (52%). The mean age was 66±11 years (range 43–87). Thrombus was detected in 13 patients (27%) 11 were confined to the left atrial appendage, 1 to the atrial body and appendage, and 1 to the left upper pulmonary vein. Prevalence of atrial thrombus was not different among those patients with or without previous stroke [4/16 (25%) vs 9/32 (28%), p=NS] or between patients > 65 years and patients 65 years old (p=NS). Atrial thrombus was detected more frequently in patients with reduced left ventricular global systolic function than in those with normal function [7/14 (50%) vs 6/34 (17%), p<0.05]. In patients with spontaneous contrast echoes in the left atrium, thrombi were visualized more often than in those without spontaneous echoes [10/24 (41%) vs 3/24 (12%), p<0.05]. The finding of the atrial spontaneous contrast echoes was more frequent among patients with reduced left ventricular global systolic function [11/14 (78%) vs 13/34 (37%), p<0.02].We conclude that in hospitalized patients with non-rheumatic atrial fibrillation the prevalence of left atrial thrombus is high. Reduced left ventricular global systolic function identifies a subset of patients at high risk for formation of thrombus in the left atrium.     

Atrial peptides, ANP(1-98) and ANP(99-126) in health and disease in an elderly population

Circulating immunoreactive atrial natriuretic peptide, Ir ANP(99-126)and the N-terminal fragment of the prohormone, Ir ANP(1–98)were measured in two population samples from the general populationof Gothenburg, Sweden. A group of 85-year olds (974 subjects)and a group of 40-year olds (191 subjects) were investigatedin respect of cardiovascular, renal and metabolic disease. Ir ANP(99-126) and Ir ANP(1-98) were significantly higher inthe 85-year olds compared to tile 40-year olds, and were significantlyincreased in subjects with congestive heart failure, ischaemicheart disease, atrial fibrillation and renal dysfunction butnot in subjects with hypertension. Eighty-five-year-old subjectswho were on treatment with digitalis, ß-adrenergic-blockers,nitrates and diuretics had significantly increased Ir ANP(99-126)and Ir ANP(1-98). In multivariate analysis Ir ANP(99-126) concentrationswere predictive for congestive heart failure, ischaemic heartdisease, atrial fibrillation and treatment with ß-blockersand anti-depressant drugs. Ir ANP(1–98) was predictivefor congestive heart failure, ischaemic heart disease, atrialfibrillation, diabetes mellitus, renal failure and drug treatmentwith ß-blockers and neuroleptics. We conclude that measurements of circulating concentrationsof Ir ANP(99-126) and/or Ir ANP(1-98) may add valuable informationin the diagnosis of congestive heart failure and ischaemic heartdisease in an elderly population. It remains to be determinedwhether routine measurements of circulating Ir ANP(99–126)and Ir ANP(1–98) may be of value in predicting currentcardiovascular disease for the individual patient.     

老年急性脑梗死患者血浆内皮素、心钠素的动态变化及其临床意义

目的:测定老年急性脑梗死患者血浆内皮素(ET)及心钠素(ANP)含量的动态变化,并探讨ET,ANP在老年急性脑梗死过程中的作用。方法:用放射免疫测定(RIA)法测定老年急性脑梗死组109例,冠心病组87例和对照组(健康志愿者)60例的血浆ET,ANP水平。结果:老年急性脑梗死患者发病后d2,15,30的血浆ET,ANP含量分别(141.3±10.7),(142.7±18.2);(123.6±4.3),(118.6±12.1);(85.4±15.7),(101.9±9.3)pg·mL~(-1),老年冠心病患者和对照组入组初血浆ET,ANP含量分别为(85.7±10.2),(103.9±9.3);(45.7±12.2),(67.4±9.5)pg·mL~(-1)。老年急性脑梗死患者和老年冠心病患者血浆ET,ANP水平较对照组明显升高(P<0.05),且随时间延长,老年急性脑梗死患者血浆ET,ANP含量均逐渐降低。结论:ET,ANP与老年急性脑梗死的发生、发展密切相关。