Evaluation of left ventricular contractile performance from baseline stress-shortening data in humans: comparison with pharmacological afterload challenge

The purpose of this study was to evaluate whether the baseline stress-shortening data reflect the contractile state adequately and give results comparable to the evaluation of the end-systolic stress-shortening relationships using pharmacological manipulation of afterload. Five groups were studied (total 152 patients): a control group of 30 healthy volunteers, 32 patients after surgical correction of infantile tetralogy of Fallot, 50 patients treated for childhood malignancies with doxorubicin, 17 patients with left ventricular hypertrophy due to systemic hypertension, and 23 patients with congestive cardiomyopathy. In all patients except those with congestive cardiomyopathy, afterload was altered pharmacologically to evaluate the individual stress-shortening relationship. In all patients the baseline stress-shortening data were evaluated, as well as their relative positions to two predefined normal ranges for the relationship between end-systolic stress and shortening. Additionally, a slope value was calculated from the baseline data of the five groups studied and compared with the data obtained by pharmacological afterload increment. Our data show that the comparison of individual baseline data of end-systolic wall stress and fractional shortening with predefined normal ranges for the relationship between end-systolic stress and shortening is inadequate. The appropriate normal range to compare with is the 95% confidence interval of baseline stress-shortening data in normal subjects. Also the calculation of a slope value from the baseline stress-shortening data of a group of patients seems to be inappropriate. Such a slope value does not necessarily reflect the contractile state, as the specific conditions leading to variations of end-systolic wall stress are undefined and not standardized, and the correlation between baseline stress-shortening data depends largely on the influence of the end-systolic dimension on both parameters.     

Effects of posture and pneumoperitoneum during anaesthesia on the indices of left ventricular filling

Background. Laparoscopic surgery requires the use of pneumoperitoneum (PP). When combined with positional changes, pneumoperitoneum may cause marked circulatory alterations.
Methods. Eight anaesthetized cardiovascularly healthy patients, scheduled for laparoscopic cholecystectomy, were studied before and during pneumoperitoneum in three different postures (supine, Trendelenburg and reversed Trendelenburg), employing transesophageal echocardiography and pulmonary artery pressure monitoring.
Results. PP significantly increased end-diastolic area (EDA) and pulmonary capillary wedge pressure (PCWP) irrespective of posture. PCWP was significantly influenced by postural changes, whereas EDA was not. Further, changes in EDA and PCWP covaried during the investigation, but showed no linear correlation. Systolic function, measured as end-systolic area (ESA) and fractional area shortening (FAS), was not altered. Diastolic function, as assessed by the velocity rate of the trans-mitral flow during the early filling phase (E) and the atrial contraction (A), showed no change of the E/A ratio, whereas after the induction of PP there was a significant reduction of the E component.
Conclusions. In cardiovascularly healthy patients, the left ventricular volume is increased during pneumoperitoneum. Further, changes in invasive pressure determinations (PCWP) do not correlate linearly with changes in volume indices of left ventricular filling (EDA).     

3-D echocardiographic imaging of double aortic arch.

Delineation of arch abnormalities is difficult by conventional 2-D echocardiography and MRI has been the investigation of choice. 3-D echocardiography is increasingly used in congenital heart disease for both functional anatomy and morphology. This case report demonstrates that 3-D echocardiography can be used in delineating arch anomalies, which can avoid further imaging that needs a general anaesthetic.     

Imaging of thoracic aortic dissection

Acute thoracic aortic dissection has a high mortality if untreated, so the diagnosis must be rapidly made if mortality is to be lowered significantly. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause for death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 of 12 patients studied and correctly classified the type in only five. Aortography was performed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were performed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention.     

Assessment of Aortic Coarctation and Collateral Circulation By Biplane Transesophageal Echocardiography

Our experience in using biplane transesophageal echocardiography in the assessment of coarctation of the aorta is described.     

Transoesophageal echocardiography in heart disease—old technologies, new tricks

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, ‘new tricks’ in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection, TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.     

彩色多普勒超声血流图在心脏手术中的应用(附19例病例分析)

在心脏手术中应用多普勒彩色超声心动仪直接探测和观察19例患者,其中风湿性心瓣膜病11例、先天性心脏病7例、左心房粘液瘤1例。风心病及左房粘液瘤患者手术前、中检查的结果基本一致;先心病术前诊断符合率为84.2％(5/7),术中诊断符合率为100％。本文对检查结果作了分析讨论,并提出符合我国情况的有关检查设想。     

经食管超声心动图在心血管手术麻醉与监测中的应用

目的　评价经食管超声心动图 (TEE)在心血管手术麻醉中的价值。方法　本组共完成 1 2 2例TEE监测。主要观察指标 :(1 )对 4 1例瓣膜置换患者的瓣膜作返流和狭窄分级及评价机械或生物瓣的功能 ;(2 ) 4 8例不停跳冠状动脉搭桥 (CABG)患者手术前后心功能变化〔①面积减少分数(FAC) ;②E波与A波峰值流速比率 (E/A)和各自的流速时间积分比率 (VTIE/VTIA) ;③E波减速时间 (DT) ;④心脏指数 (CI)〕 ;(3)手术前后对 2 0例不停跳CABG患者左室室壁 (前壁、后壁、侧壁和室间隔 )运动分级 ;(4 )监测先心病矫正前后心脏结构变化。结果　TEE检测瓣膜病变与经胸超声结果一致 ,手术后瓣膜活动正常。术后FAC、CI和VTIE/VTIA分别为 (0 5 2± 0 0 8)、(2 6 4± 0 6 9)L·min 1 ·m 2 和 1 2 9± 0 1 8,与术前比较 (0 4 2± 0 0 9)、(2 0 5± 0 4 8)L·min 1 ·m 2 和 1 1 4± 0 1 6有显著性差异 (P <0 0 5 ) ;术后E/A 0 86± 0 2 1与术前 0 77± 0 1 8比较P <0 0 1。DT无显著性变化。术前节段性室壁运动异常大于 2级的占 1 0 % ,术后为 5 %。结论　在心血管手术中 ,TEE是一种新的有用的监测技术     

Bilocular atrial malignant mesenchymoma causing mitral and localized pulmonary vein flow obstruction: diagnosis by transoesophageal echocardiography.

Cardiac malignant mesenchymoma is an extremely rare malignancy with poor prognosis. We report a patient presenting with a history and clinical findings typical of mitral stenosis. Transthoracic echocardiography showed a mass on the thickened posterior mitral leaflet. Transoesophageal echocardiography revealed two tumoural masses: one on the atrial side of the posterior mitral leaflet causing mitral obstruction, the other arising in the region of the right lower pulmonary vein orifice and obstructing inflow through this vein.     

Digital echocardiography in myocardial infarction

Probably the most under-utilised application of echocardiography is in patients with coronary artery disease (CAD). This under-utilisation is striking since echocardiography can be very valuable in evaluating the natural history and therapy of CAD. One reason why echocardiography is not being utilised to its fullest is because of the reliance on videotape to record and display echocardiograms. This medium is time consuming and inconvenient for clinicians to review studies, it is not ideal for detecting subtle wall motion abnormalities, and videotape is impractical for comparing serial studies. Recording and storing echocardiograms on a digital medium overcomes these difficulties. Digital cine loops of single cardiac cycles provide great versatility. Multiple views or studies can be displayed simultaneously, subtle changes in wall motion are more easily detected and different views, or serial studies, can be readily compared. Such images can be displayed on computers on the ward or in the coronary care unit (CCU) and be available 24 hours a day, seven days a week at the convenience of the clinician. One does not need to find a recording on a two hour videotape, which may be in the ultrasound instrument, and one can view the exam in 30 sec instead of 5 to 10 min. Regional and global left ventricular function is one of the most important manifestations of CAD. With new therapeutic efforts at restoring myocardial function and limiting infant expansion, assessing LV function is more important than ever. Digital echocardiography is an extremely practical and convenient way for clinicians to obtain this information.