A Comparison of Left Ventricular Performance Indices Measured by Transesophageal Echocardiography with Automated Border Detection

Background: Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure-area loops and pressure-dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure-dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices.

Methods: Using transesophageal echocardiography with automated border detection, FAC and Vcfc were obtained in 23 patients after cardiopulmonary bypass. Left ventricular pressures were obtained with a left ventricular catheter. Preload reduction by inferior vena caval occlusion was used to obtain end-systolic elastance (Ees), preload recruitable stroke force (PRSF), and dP/dtmax [middle dot] EDA-1 (EDA = end-diastolic area). In 11 patients, the measurements were repeated at 1 end-tidal minimum alveolar concentration of halothane or isoflurane. The results are expressed as mean +/- SD.

Results: After cardiopulmonary bypass, FAC was 31.1 +/- 7.9%, Vcfc was 0.6 +/- 0.2 circ [middle dot] s-1, Ees was 25.8 +/- 11.6 mmHg [middle dot] cm-2, PRSF was 60.8 +/- 26.6 mmHg, and dP/dtmax [middle dot] -EDA-1 was 245 +/- 123.4 mmHg [middle dot] s-1 [middle dot] cm-2. At 1 minimum alveolar concentration of a volatile anesthetic agent, FAC, Vcfc, and dP/dtmax [middle dot] EDA-1 remained unchanged. Significant decreases in Ees (19%) and PRSF (28%) were observed.     

Left ventricular ejection fraction: single-plane and multiplanar transesophageal echocardiography versus equilibrium gated-pool scintigraphy

The relative accuracy and precision of estimating left ventricular ejection fraction (EF) in dogs were assessed by two-dimensional transesophageal echocardiography (2D-TEE) and by three-dimensional transesophageal echocardiographic (3D-TEE) imaging and reconstruction. This assessment was accomplished by comparing each echocardiographic method to a gated equilibrium blood pool radionuclide (RN) standard. By using both correlation and regression analysis, 2D-TEE performed reasonably well in estimating RNEF (correlation coefficient [r] = 0.80, slope = 1.01, intercept = 6.37, standard error of the estimate [SEE], 8.98), but not as well as 3D-TEE (r = 0.86, slope = 0.83, intercept = 3.38, SEE, 5.74). Using Altman and Bland's methods of comparison analysis, it was found that 2D-TEE overestimated RNEF by 7% (standard deviation [SD], 8.8). This degree of overestimation was not consistent across the range of measurement. In contrast, 3D-TEE slightly underestimated RNEF by less than 3% and showed less variability (SD, 6.0). The accuracy of the 3D-TEE determinations was not dependent on the magnitude of EF. Additionally, a significantly higher proportion of the 2D-TEE measurements (0.30) compared with the 3D-TEE measurements (0.10) differed from RN values by more than 10% (P = 0.009, McNemar's test). At the clinically important low end of the EF range (RNEF less than or equal to 35%), 2D-TEE may be expected (with 95% confidence) to be within -15% to +28% EF of reference values, whereas 3D-TEE can be expected to be within -8% to +5% EF relative to RN.(ABSTRACT TRUNCATED AT 250 WORDS)     

Circumflex artery motion; a new angiographic method for assessment of left ventricular function

OBJECTIVE: To evaluate the usefulness of circumflex artery motion (CAM) for assessment of left ventricular (LV) function. DESIGN: Seventy-three consecutive patients referred for coronary angiography and LV angiography were included. Ejection fraction (EF) was calculated from LV angiography and CAM was measured from coronary angiography. RESULTS: The ratio between CAM and the end-diastolic length of the ventricle, which can be denominated long-axis fractional shortening (FS(L)), was found to be a better index of LV function than CAM per se. There was a significant linear correlation between EF and FS(L) (r = 0.81, SEE = 8.2, p < 0.001). When values of FS(L) > or =10% were selected to define a normal EF (> or =50%) there was a sensitivity of 95% and a specificity of 93%. Visual estimation of EF from CAM was not as good as the use of calculated FS(L) but may me useful as a fast screening method. CONCLUSION: LV systolic function can be assessed by studying CAM recorded by coronary angiography.     

Determination of right ventricular function by transesophageal echocardiography: impact of proximal right coronary artery stenosis

STUDY OBJECTIVE: To investigate whether transesophageal echocardiography (TEE) can provide accurate information on right ventricular (RV) function in patients with right coronary artery (RCA) stenosis, given that a decrease in blood supply from the RCA may invalidate the use of single 2-D echocardiography imaging plane as a guide to RV function. DESIGN: Prospective, nonblinded study. SETTING: University hospital. PATIENTS: 30 adult patients undergoing elective cardiac or vascular procedures. INTERVENTIONS: Patients were classified into two groups according to the presence or absence of the proximal RCA (segment 1 or 2) stenosis. Group A patients had no obstructive lesions in the proximal RCA (n = 15). Group B patients had 75% or greater obstructive lesions in the proximal RCA (n = 15). MEASUREMENTS AND MAIN RESULTS: After induction of anesthesia, RV function was evaluated by both fast-response thermodilution pulmonary artery catheter and TEE. Transesophageal echocardiography-derived RV fractional area change (FAC) and tricuspid annular plane systolic excursion ratio (TAPSE ratio) were compared with thermodilution-derived RV ejection fraction (EF) using linear regression analysis. Transesophageal echocardiography-derived RV end-diastolic area (EDA) was compared with thermodilution-derived end-diastolic volume (EDV). Both methods showed a good correlation in RV, EDV, and EF in Group A, but no correlations in Group B. CONCLUSIONS: Transesophageal echocardiography does not provide reliable information on RVEF and EDV when proximal RCA stenosis is present.     

Multicenter Study of Target-Controlled Infusion of Propofol-Sufentanil or Sufentanil-Midazolam for Coronary Artery Bypass Graft Surgery

Background: The use of target-controlled infusions of anesthetics for coronary artery bypass graft surgery has not been studied in detail. The effects of target-controlled infusions of propofol or sufentanil, supplemented by infusions of sufentanil or midazolam, respectively, were evaluated and compared.

Methods: At 14 clinical sites, 329 patients were given a target-controlled infusion of propofol (n = 165) to produce effect-site concentration (Ce) of greater or equal to 3-micro gram/ml or a target-controlled infusion of sufentanil (n = 164). Sufentanil or midazolam, respectively, also were infused. Systolic hypertension, hypotension, tachycardia, and bradycardia were assessed by measuring heart rate and blood pressure every minute during operation. Myocardial ischemia was assessed perioperatively by monitoring ST segment deviation via continuous three-lead Holter electrocardiography, and it was evaluated during operation by monitoring left ventricular wall motion abnormality via transesophageal echocardiography.

Results: The measured cardiovascular parameters were satisfactory and usually similar for the patients receiving propofol-sufentanil or sufentanil-midazolam. The primary endpoint of the percentage of patients with intraoperative ST segment deviation (23 plus/minus 6% vs. 24 plus/minus 6%, P = 0.86) did not differ significantly between the two groups. The incidence of left ventricular wall motion abnormality shown on transesophageal echocardiography before (19 plus/minus 4% vs. 26 plus/minus 4%, P = 0.25) and after (23 plus/minus 4% vs. 31 plus/minus 5%, P = 0.32) cardiopulmonary bypass also did not differ significantly for the two groups. Changes in intraoperative target concentration were more frequent with propofol-sufentanil anesthetic than with sufentanil-midazolam (11.7 plus/minus 7.1 vs. 7.3 plus/minus 3.6, P <0.001). The incidence of intraoperative hypotension (77% vs. 55%, P <0.001), the use of inotropic/vasopressor medications (93% vs. 84%, P = 0.01), and the administration of crystalloids (2.8 plus/minus 1.4 L vs. 2.4 plus/minus 1.2 L, P < 0.001) were significantly greater in the propofol-sufentanil group. Conversely, the incidence of intraoperative hypertension (43% vs. 54%, P = 0.05) and the use of antihypertensive/vasodilator medications (70% vs. 90%, P < 0.001) were significantly less in the propofol-sufentanil group.     

Early preload adaptation in septic shock? A transesophageal echocardiographic study

BACKGROUND: An accepted concept in septic shock is that preload adaptation by acute left ventricular dilatation, when occurring spontaneously or with the aid of volume loading, permits maintenance of an adequate cardiac output, leading to final recovery. From a physiologic point of view, this concept appears debatable because a normal pericardium exerts a restraining action on a normal heart. METHODS: During a 26-month period, the authors investigated, by transesophageal echocardiography, 40 patients hospitalized in their unit for an episode of septic shock. Transesophageal echocardiography was performed in the first hours after admission, proceeded by correction of any hypovolemia, and stabilization of arterial pressure by vasoactive agent infusion if necessary. Left ventricular dimensions were obtained in long- and short-axis views, permitting calculation of left ventricular ejection fraction (long axis) and fractional area contraction (short axis). Stroke index was simultaneously measured by the Doppler technique. RESULTS: Stroke index was strongly correlated with both echocardiographic left ventricle ejection fraction (r = 0.75; P < 0.0001) and left ventricle fractional area contraction (r = 0.76; P < 0.0001), whereas it was independent of echocardiographic left ventricle diastolic dimensions. CONCLUSIONS: The transesophageal echocardiography study was unable to confirm the reality of the concept of early preload adaptation by left ventricular dilatation in septic shock. Conversely, because left ventricular volume always remained in a normal range after correcting hypovolemia, systolic function was the unique determinant of stroke index in septic shock.     

The effect of landiolol on hemodynamics and left ventricular function in patients with coronary artery disease

STUDY OBJECTIVE: To examine the effect of landiolol (normal dose) on hemodynamics and left ventricular (LV) function. DESIGN: Prospective, observational, repeated-measures study. SETTING: University hospital. PATIENTS: 56 adult patients who were diagnosed with angina pectoris and who underwent elective off-pump coronary artery bypass surgery. INTERVENTIONS: Patients were divided into two groups based on a preoperative LV ejection fraction (EF) 50% or higher (normal EF group, n = 28) and lower than 50% (low EF group, n = 28). Hemodynamics and LV function were recorded using a pulmonary artery catheter and transesophageal echocardiography at three time points (before administration of landiolol, immediately before completion of administration, and 15 minutes after completion of administration). MEASUREMENTS: Individual hemodynamic data were obtained using a pulmonary artery catheter, and individual parameters were determined from LV short-axis views in transesophageal echocardiography. MAIN RESULTS: Mean preoperative EFs were 57% +/- 5% and 47% +/- 3% in the normal and low EF groups, respectively. In both groups, landiolol produced a significant decrease in heart rate (HR), which then returned to baseline 15 minutes after completion of administration. A significant decrease in mean arterial pressure occurred in the low EF group, but the decrease was within 30% of baseline. In the normal EF group, there was no decrease in cardiac index, but a significant increase in stroke index, in addition to an increase in stroke volume. In the low EF group, cardiac index significantly decreased along with the decrease in HR, but there was no increase in end-diastolic volume or stroke volume. CONCLUSIONS: Administration of landiolol using the presently recommended dosage and administration route causes a decrease in HR without aggravation of hemodynamics in patients with normal cardiac function, but in patients with preoperative EF lower than 50%, it may lead to further deterioration of cardiac function due to a decrease in HR.     

Transesophageal echocardiography values for left ventricular end-diastolic area and pulmonary vein and mitral inflow Doppler velocities in patients undergoing coronary artery bypass graft surgery

OBJECTIVE: To determine left ventricular end-diastolic area (EDA) and pulmonary vein and mitral inflow Doppler velocities in patients undergoing coronary artery bypass graft (CABG) surgery using transesophageal echocardiography (TEE). To examine the effects of age, sex, and left ventricular function on these values. DESIGN: Prospective observational study; all measurements performed before cardiopulmonary bypass. SETTING: Tertiary referral teaching hospital. PARTICIPANTS: Eighty-six elective CABG surgery patients. INTERVENTIONS: Intraoperative TEE was performed in all patients. MEASUREMENTS AND MAIN RESULTS: The left ventricular EDA was measured at the midpapillary level, excluding the papillary muscles. Mean EDA for patients with normal left ventricular function, defined by fractional area change (FAC) 0.50 or greater, was 10.66 cm2 and when indexed to body surface area was 5.6 cm2/m2. The EDA was greater in patients with impaired left ventricular function (FAC < 0.50). Mean EDA was 14.84 cm2, and EDA/body surface area was 7.8 cm2/m2. In patients with FAC 0.50 or greater, mean peak pulmonary vein Doppler velocities were 46.10 cm/sec (systole), 31.71 cm/sec (diastole), and 1.50 (ratio systole to diastole). Mean peak mitral inflow Doppler velocities were 57.25 cm/sec (early diastole), 57.21 cm/sec (late diastole), and 1.10 (ratio early to late), and deceleration time was 216 msec. Age, sex, and left ventricular function were not significant predictors of Doppler variables. CONCLUSIONS: Values are presented for a predominantly white population undergoing cardiac surgery. Left ventricular dysfunction is associated with increased left ventricular EDA measurements.     

Prognostic value of biventricular function in hypotensive patients after cardiac surgery as assessed by transesophageal echocardiography.

In patients after cardiac surgery, hypotension, defined as a mean arterial pressure less than 65 mmHg despite adequate filling pressures and positive inotropic medication, poses a problem. In addition, it is often difficult to determine whether these patients have suffered irreversible myocardial injury or if they are likely to recover. In this study, left and right ventricular function, as assessed by transesophageal echocardiography (TEE), was related to mortality both (1) quantitatively, using fractional area change (FAC), and (2) qualitatively, using a segmental wall motion analysis, which assigned a score to myocardial wall segments, in order to determine whether this technique can be used to predict survival. Mortality rate was very high in patients with biventricular and especially right ventricular failure (FAC less than 35%). Left and right ventricular wall motion abnormality indices were significantly better in survivors compared to nonsurvivors, but no distinct cut-off value could be determined. A wall motion index derived from only 6 segments at the mid-papillary muscle level was found to be as reliable as one based on 16 segments of the entire left ventricle. Thus, TEE provided information about the degree of left and right ventricular dysfunction by using a single cross-section at the papillary muscle level. It identified patients at high risk of death, ie, those with compromised right and biventricular function.     

Clinical assessment of indication for ACE-inhibitor treatment early after acute myocardial infarction.

An investigation was conducted to assess whether an algorithm based on simple clinical information would suffice to classify patients with acute myocardial infarction, with respect to indication for angiotensin-converting-enzyme inhibitor treatment. One hundred consecutive patients with myocardial infarction were prospectively studied. Based on clinical, radiological, electrocardiographic and biochemical information, the patients were classified as having (a) significantly depressed left ventricular function (ejection fraction < or = 40%) justifying treatment with angiotensin-converting-enzyme inhibitors (ACEI), (b) preserved ventricular function (ejection fraction > 40%) making ACEI unnecessary, or (c) indeterminate ventricular function, requiring further examination. Using a blinded design, ejection fraction was determined by echocardiography and radionuclide ventriculography. A clinical assumption of reduced left ventricular function had a predictive value of an echocardiographically determined ejection fraction < or = 40% of 83% (n = 23). Clinical criteria of good ventricular function had a predictive value of ejection fraction > 40% of 96% (n = 24). In these two groups clinical misclassification occurred in five patients with ejection fraction within the range of 39-45%. Left ventricular function was found to be clinically indeterminate in 53 of the 100 patients. Ejection fraction values assessed by radionuclide ventriculography (n = 44) were on average 9.3%-points lower than echocardiographic values. The indication for ACEI can apparently be determined on the basis of readily available clinical information in approximately 50% of patients with acute myocardial infarction.     

Efficacy of transesophageal echocardiography as a perioperative monitor in patients undergoing cardiovascular surgery. Analysis of 149 consecutive studies

To evaluate the usefulness of transesophageal echocardiography as a perioperative monitor in patients undergoing cardiovascular surgery, 149 consecutive patients were studied since 1985. Left ventricular function was assessed by measurement of left ventricular dimension and ejection fraction in patients with valvular disease. This monitoring was useful in detecting the changes in left ventricular performance in patients with volume overload and in managing patients in the early postoperative period. Cardiac tamponade was clearly demonstrated before changes in electrocardiogram and hemodynamic data. In 27 patients, transesophageal color Doppler echocardiography was used to confirm that there was no residual regurgitation immediately after valvular reconstructive surgery. Transesophageal color Doppler echocardiography was also useful in detecting the entry of false lumen before surgery in 7 patients with dissecting aortic aneurysm. There were no unsuccessful introductions, no traumatic or thermal injuries, 18 patients (12.1%) with hoarseness and 5 patients (3.4%) with transient arrhythmia. In conclusion, transesophageal echocardiography provides a good imaging window to the heart and great vessels perioperatively. This expedient, safe informative imaging method can be used more routinely in patients during surgery.     

Why do patients with ischemic cardiomyopathy and a substantial amount of viable myocardium not always recover in function after revascularization?

OBJECTIVE: In patients with ischemic cardiomyopathy and a substantial amount of dysfunctional but viable myocardium, myocardial revascularization may improve left ventricular ejection fraction. The aim of this study was to evaluate why not all patients with a substantial amount of viable tissue recover in function after revascularization. METHODS: A total of 118 consecutive patients with a depressed left ventricular ejection fraction (on average 29% +/- 6%) due to chronic coronary artery disease underwent myocardial revascularization. Before revascularization all patients underwent dobutamine stress echocardiography to assess regional dysfunction, left ventricular volumes, and myocardial viability as well as radionuclide ventriculography to determine the left ventricular ejection fraction. Next, 3 to 6 months after revascularization, the left ventricular ejection fraction and regional contractile function were reassessed. Improvement of left ventricular ejection fraction > or = 5% following revascularization was considered clinically significant. RESULTS: Dobutamine stress echocardiography revealed that 489 (37%) of the 1329 dysfunctional segments were viable. A total of 61 (52%) patients had a substantial amount of viable myocardium (> or = 4 viable segments). In these 61 patients the global function was expected to recover > or = 5% after revascularization. However, left ventricular ejection fraction did not improve in 20 (33%) of 61 patients despite the presence of substantial viability. Clinical characteristics and echocardiographic data were comparable between patients with and without improvement. However, patients without improvement had considerably larger end systolic volumes (153 +/- 41 mL vs 133 +/- 46 mL, P =.007). The likelihood of recovery of global function decreased proportionally with the increase of end systolic volume (P <.001, R = 0.43, n = 61). Receiver operating characteristic curve analysis demonstrated that an end systolic volume > or = 140 mL had the highest sensitivity/specificity to predict the absence of global recovery. CONCLUSIONS: In patients with ischemic cardiomyopathy not only the amount of dysfunctional but viable myocardium but also the extent of left ventricular remodeling determines the improvement in function following myocardial revascularization. Patients with a high end systolic volume due to left ventricular remodeling have a decreased likelihood of improvement of global function.     

Anesthetic management of a child with dilated cardiomyopathy associated with congenital fiber-type disproportion

A 3-year-old girl, who presented with dilated cardiomyopathy in conjunction with congenital fiber-type disproportion, underwent open reduction for congenital dislocation of the hip. Preoperative echocardiography demonstrated left ventricular dilatation with an ejection fraction (EF) of 0.33. Anesthesia was induced with intravenous ketamine and fentanyl, and maintained with fentanyl administered incrementally to a total dose of 10 micrograms.kg-1 and 1-1.5% isoflurane. During operation, we continuously monitored left ventricular wall motion and measured left ventricular diastolic dimension (LVDd), systolic dimension (LVDs), cardiac output (CO), EF, and fractional shortening (FS) with transesophageal echocardiography (TEE). At the end of surgery, preload (LVDd) and LV contractility (CO, EF, FS) decreased, but LV wall motion remained almost stable throughout the procedure. In conclusion, TEE was useful for intraoperative management of a child with dilated cardiomyopathy.     

Comparison of transesophageal echocardiographic and scintigraphic estimates of left ventricular end-diastolic volume index and ejection fraction in patients following coronary artery bypass grafting

Transesophageal echocardiography (TEE) has become a commonly used monitor of left ventricular (LV) function and filling during cardiac surgery. Its use is based on the assumption that changes in LV short-axis ID reflect changes in LV volume. To study the ability of TEE to estimate LV volume and ejection immediately following CABG, 10 patients were studied using blood pool scintigraphy, TEE, and thermodilution cardiac output (CO). A single TEE short-axis cross-sectional image of the LV at the midpapillary muscle level was used for area analysis. Between 1 and 5 h postoperatively, simultaneous data sets (scintigraphy, TEE, and CO) were obtained three to five times in each patient. End-diastolic (EDa) and end-systolic (ESa) areas were measured by light pen. Ejection fraction area (EFa) was calculated (EFa = (EDa - ESa)/EDa). When EFa was compared with EF by scintigraphy, correlation was good (r = 0.82 SEE = 0.07). EDa was taken as an indicator of LV volume and compared with LVEDVI which was derived from EF by scintigraphy and CO. Correlation between EDa and LVEDVI was fair (r = 0.74 SEE = 3.75). The authors conclude that immediately following CABG, a single cross-sectional TEE image provides a reasonable estimate of EF but not LVEDVI.     

Mitral valve repair in patients with end stage cardiomyopathy: who benefits?

Objective: Patients with end stage cardiomyopathy frequently present with additional severe mitral regurgitation. We analyzed the outcome of mitral valve reconstruction in this high risk patient group. Methods: Sixty-six patients with significant mitral regurgitation and an ejection fraction (EF) below 30% (dilated CARDIOMYOPATHY=53, ischemic cardiomyopathy (ICM)=13) were retrospectively evaluated from 07/96 and 02/02. All received annuloplasty ring implantation and additional repair (n=4) if required. Mean follow-up was 28±18 months. Results: Mitral valve repair (MVR) was technically feasible in all patients. Intraoperative transesophageal echocardiography (TEE) revealed none (n=60) or only trivial (n=6) residual mitral regurgitation. Thirty day mortality was 6.1%. Actuarial survival after 1 and 5 years was 86±4 and 66±8%, respectively. During follow-up seven patients were transplanted due to lack of clinical improvement after 10±7 months (range 1–23). Echocardiography revealed a significant improvement in EF (25±10.5% pre-op, 34±15% post-op) and a slight decrease in left ventricular end-diastolic diameter (69±10 mm pre-op, 67±13 mm follow up). Patients were in NYHA functional -class 3 (median) preoperatively and in class 2 at long term-follow-up. Gender, left ventricular enddiastolic diameter, preoperative ejection fraction or type of surgical approach (sternotomy, right lateral minithoracotomy) had no significant influence on patient outcome. Patients with ICM or patients older than 60 years showed an increased risk for clinical events both early post-operatively and at long-term follow-up. Conclusion: MVR can be performed with low perioperative morbidity and mortality even in patients with advanced heart failure, modifying selection criteria for potential candidates may further improve long term outcome.     

Transesophageal echocardiography predicts successful withdrawal of ventricular assist devices.

Transesophageal echocardiography has been found to be an effective technique for the real-time assessment of myocardial and valvular function in postoperative patients. To determine the value of transesophageal echocardiography in patients with mechanical assist devices, we performed daily, bedside transesophageal echocardiography on 16 patients with right (n = 3), left (n = 1), or biventricular assist devices (n = 12). We obtained four-chamber and short-axis views in all patients. Valvular function and the presence of left-to-right shunts were evaluated by means of color flow Doppler imaging. During the echocardiographic study ventricular assist device flow was diminished to less than 1.5 L/min, and inotropic agents (dobutamine or epinephrine) were given to assess ventricular reserve. Changes in day-to-day ventricular function were assessed in comparisons made by two observers (one unaware of the study sequence) using a semiquantitative method for wall motion analysis. The left ventricular wall motion scores in the patients successfully weaned from left or biventricular assist devices (n = 5) improved (14.2 +/- 1.6 versus 8.2 +/- 1.5, p < 0.0001). The scores did not improve in patients who remained dependent on the devices (n = 8). Two patients with only right ventricular assist devices were successfully weaned after documentation of improvement of right ventricular function by transesophageal echocardiography. Transesophageal echocardiography documented a clot compressing the heart in three patients; intracavitary thrombi were seen in two other patients. Marked hemodynamic improvement occurred after surgical decompression. In conclusion, transesophageal echocardiography is a safe, effective method for the assessment of ventricular function of patients on ventricular assist device support. In addition, it allows one to assess valvular function and the presence or absence of impaired ventricular filling.     

Early Preload Adaptation in Septic Shock?: A Transesophageal Echocardiographic Study

Background: An accepted concept in septic shock is that preload adaptation by acute left ventricular dilatation, when occurring spontaneously or with the aid of volume loading, permits maintenance of an adequate cardiac output, leading to final recovery. From a physiologic point of view, this concept appears debatable because a normal pericardium exerts a restraining action on a normal heart.

Methods: During a 26-month period, the authors investigated, by transesophageal echocardiography, 40 patients hospitalized in their unit for an episode of septic shock. Transesophageal echocardiography was performed in the first hours after admission, proceeded by correction of any hypovolemia, and stabilization of arterial pressure by vasoactive agent infusion if necessary. Left ventricular dimensions were obtained in long- and short-axis views, permitting calculation of left ventricular ejection fraction (long axis) and fractional area contraction (short axis). Stroke index was simultaneously measured by the Doppler technique.

Results: Stroke index was strongly correlated with both echocardiographic left ventricle ejection fraction (r = 0.75;P < 0.0001) and left ventricle fractional area contraction (r = 0.76;P < 0.0001), whereas it was independent of echocardiographic left ventricle diastolic dimensions.     

Timing of transesophageal echocardiography in diagnosing patent foramen ovale in patients supported with left ventricular assist device

Left ventricular assist devices unload the left ventricle and decrease left atrial pressure. This hemodynamic change may cause a right to left atrial shunt and hypoxemia in patients with patent foramen ovale. We prospectively studied the best time for performing diagnostic transesophageal echocardiography in left ventricular assist device patients. Intraoperative transesophageal echocardiography was performed in 14 patients before cardiopulmonary bypass was initiated and after left ventricular assist device was implanted. No patent foramen ovale was detected when transesophageal echocardiography was done before bypass, but a patent foramen ovale was found in 3 patients when transesophageal echocardiography was performed after left ventricular assist device was activated. Patent foramen ovale was confirmed by inspection in all three patients and surgically closed during the same procedure. There were no patent foramen ovale closure-related complications.     

Echocardiographic assessment at rest and during stress in patients with intermittent claudication

Objective. Skeletal muscle perfusion during walking relies on complex interactions between cardiac activity and vascular control mechanisms, why cardiac dysfunction may contribute to intermittent claudication (IC) symptoms. The study aims were to describe cardiac function at rest and during stress in consecutive IC patients, to explore the relations between cardiac function parameters and treadmill performance, and to test the hypothesis that clinically silent myocardial ischemia during stress may contribute to IC limb symptomatology. Design. Patients with mild to severe IC (n?=?111, mean age 67 y, 52% females, mean treadmill distance 195 m) underwent standard echocardiography, dobutamine stress echocardiography (SE) and treadmill testing. The patient cohort was separated in two groups based on treadmill performance (HIGH and LOW performance). Results. Ten patients (9%) had regional wall motion abnormalities of which three had left ventricular ejection fraction <50% at standard echocardiography. A majority had lower than expected systolic- and diastolic ventricular volumes. LOW performers had smaller diastolic left ventricular volumes and lower global peak systolic velocity during dobutamine stress. No patient demonstrated significant cardiac dysfunction during dobutamine provocation that was not also evident at standard echocardiography. Conclusions. Most IC patients were without signs of ischemic heart disease or cardiac failure. The majority had small left ventricular volumes. The hypothesis that clinically silent myocardial ischemia impairing left ventricular function during stress may contribute to IC limb symptomatology was not supported.

Trial registration: ClinicalTrials.gov identifier: NCT01219842.     

Significance of changes in resting left ventricular ejection fraction after coronary artery bypass grafting

The prognostic significance of changes in resting left ventricular ejection fraction was examined in 102 patients who underwent successful coronary artery bypass grafting. Between preoperative and early postoperative radionuclide ventriculography, mean resting left ventricular ejection fraction improved from 47.2% to 53.9% (p less than 0.01). Left ventricular ejection fraction increased by 5% or greater in 64 patients (63%), remained unchanged (within 4%) in 31 (30%), and decreased by at least 5% in 7 (7%). During 14 to 39 months (mean 27 months) of clinical follow-up, patients with normal preoperative left ventricular ejection fraction had a lower prevalence of recurrent angina, congestive heart failure, and mortality resulting from cardiovascular disease. Cardiovascular morbidity and mortality occurred with equal frequency for patients who did and did not show early postoperative improvement in left ventricular ejection fraction (36% versus 39%). Among 69 patients who had a third radionuclide ventriculography at late follow-up, left ventricular ejection fraction was less than the early postoperative value in 69% and less than the preoperative result in 36%. Patients with early postoperative improvement in left ventricular ejection fraction were more likely to retain resting left ventricular contractile function, at least at the preoperative level (71% versus 46%).