Transesophageal echocardiography guided enoxaparin antithrombotic strategy for cardioversion of atrial fibrillation: the ACUTE II pilot study.

BACKGROUND: Patients with atrial fibrillation >2 days' duration for whom immediate cardioversion is desired or required are commonly hospitalized for 4 or more days of antithrombotic therapy with intravenous unfractionated heparin and commencement of oral warfarin. For these early cardioversion patients, self-administered low-molecular-weight heparin (enoxaparin sodium) as "bridge" therapy to warfarin may obviate the need for hospitalization and activated partial thromboplastin time monitoring and thus potentially lower costs and enhance utility. OBJECTIVE: To compare feasibility and safety of a transesophageal echocardiography (TEE)-guided enoxaparin strategy with those of a TEE-guided unfractionated heparin strategy in patients with atrial fibrillation of >2 days' duration undergoing early electrical or chemical cardioversion. DESIGN AND SETTING: This is a randomized, multicenter clinical trial at 11 hospitals in the United States. PATIENTS AND INTERVENTION: Two hundred patients with atrial fibrillation >2 days' duration requiring early chemical or electric cardioversion will be enrolled. TEE-guided intravenous unfractionated heparin bridge therapy will be compared with TEE-guided subcutaneous enoxaparin bridge therapy. OUTCOME MEASURES: Feasibility outcomes are time to hospital discharge, patient quality of life/utility, treatment costs, and sinus rhythm. Safety outcomes are ischemic stroke, transient ischemic attack, systemic embolization, major and minor bleeding, clinical hemodynamic instability, and cardiac and cardioversion-related death for a 5-week period from enrollment. CLINICAL IMPLICATIONS: The results of this pilot study will have important clinical and economic implications for the antithrombotic management of patients with atrial fibrillation undergoing TEE-guided cardioversion.

Assessment of left internal mammary artery graft patency and flow reserve after minimally invasive direct coronary artery bypass.

Despite its merits, minimally invasive direct coronary artery bypass surgery (MIDCAB) has been criticized for variable left internal mammary artery (LIMA) graft patency rates, prompting the frequent use of postoperative LIMA angiography. Noninvasive transthoracic Doppler interrogation of LIMA grafts has recently been shown to have utility for assessing patency and flow reserve after conventional bypass surgery, but data after MIDCAB has been limited. The objective of this study was to assess LIMA graft anatomy and physiology in 54 patients after MIDCAB using angiography and noninvasive LIMA Doppler imaging. The right internal mammary artery (RIMA) was studied as a control. LIMA flow reserve in response to adenosine was evaluated in a subgroup of 18 randomly chosen patients with patent grafts. LIMA angiographic patency was 93%. Forty-four patients (81%) had obtainable LIMA Doppler data. Patent grafts had a diastolic dominant flow pattern with a peak diastolic/systolic velocity ratio of 1.3 +/- 0.6 and a percent diastolic time-velocity integral (TVI) of 70 +/- 11%. These data were significantly different than the RIMA control values of 0.2 +/- 0.1 and 30 +/- 10%, respectively (p <0.05). Occluded grafts had absent flow or a systolic dominant pattern. Adenosine-induced increases in LIMA peak diastolic velocity from 48 +/- 20 to 105 +/-28 cm/s (p <0.05 vs baseline) and diastolic TVI from 21 +/- 10 to 37 +/- 19 cm (p <0.05 vs baseline), yielding adenosine/baseline ratios of 2.4 +/- 0.9 and 2.0 +/- 0.7, respectively, which was consistent with normal flow reserve. The diastolic flow velocity reserve response was inversely related to baseline diastolic flow (r = -0.69). In conclusion, MIDCAB can be associated with a high rate of LIMA potency and favorable physiologic Doppler flow patterns. Correlation of these findings to long-term patient outcome after MIDCAB is warranted.

Surgical treatment of lipomatous hypertrophy of the interatrial septum.

We report a case of lipomatous hypertrophy of the interatrial septum in a patient with a recent syncopal episode and shortness of breath. Preoperative transesophageal echocardiography demonstrated a large tumor protruding from the interatrial septum. In addition, the patient was found to have significant coronary artery disease and a right internal carotid artery stenosis. The patient underwent successful resection of the mass with septal reconstruction, aortocoronary bypass, and right carotid endarterectomy. Histology of the mass was consistent with lipomatous hypertrophy.

Quantification of the myocardial response to low-dose dobutamine using tissue Doppler echocardiographic measures of velocity and velocity gradient.

Low-dose dobutamine echocardiography has been clinically useful in myocardial viability studies, although routine visual assessment of wall motion is subjective. The objective was to quantify the incremental myocardial response to low-dose dobutamine infusion using a new semiautomated tissue Doppler (TD) analysis system and to compare these data with routine echocardiographic measures in the same subjects. Twelve subjects had TD and routine echocardiographic studies at baseline and during 10-minute stages of dobutamine infusion at 1, 2, 3, and 5 microg/kg/min. Color TD video data were converted to a digital velocity matrix (4.5 velocity data points/mm at 500 Hz) for analysis of mitral annular velocity, endocardial velocity, and velocity gradient at each stage. Posterior wall percent thickening and ejection fraction were calculated from the routine images. Mitral annular peak systolic velocity significantly increased with only 1 microg/kg/min of dobutamine from 69 +/- 9 to 77 +/- 7 mm/s (p <0.05 vs baseline), and further incremental increases occurred with each subsequent dose. Anteroseptal and posterior wall peak endocardial velocity increased with 2 microg/kg/min of dobutamine from 33 +/- 7 to 46 +/- 15 mm/s and 50 +/- 9 to 61 +/- 10 mm/s, respectively (p <0.01 vs baseline) and further increased with 5 microg/kg/min (p <0.0001 vs 3 microg/kg/min). Posterior wall peak systolic gradient also increased with 2 microg/kg/min of dobutamine from 3.1 +/- 0.6 to 5.4 +/- 1.6 s(-1) (p <0.05 vs baseline). Routine measures of percent wall thickening or ejection fraction did not detect increases until the 3 microg/kg/min dose. TD can detect subtle alterations in contractility induced by low-dose dobutamine and has the potential to quantify regional ventricular function objectively.

Resource utilization for minimally invasive direct and standard coronary artery bypass grafting.

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCABG) has been recently reintroduced into the cardiac surgical armamentarium for selected patients with suitable coronary anatomy. We hypothesized that MIDCABG had the potential for similar immediate results with decreased perioperative morbidity and decreased resource utilization compared with standard coronary artery bypass grafting (CABG). METHODS: From January 1996 to August 1996, 17 MIDCABG patients were compared with 33 patients with left ventricular ejection fraction greater than 0.50 who underwent CABG with standard technique. No significant differences were observed between the two groups for preoperative variables that are known to affect cost and resource utilization. Length of stay in the hospital was 2.5 +/- 0.8 days for MIDCABG and 5.9 +/- 2 days for CABG (p < 0.0001); length of stay in the intensive care unit was 12.3 +/- 3.3 hours for MIDCABG compared to 32.3 +/- 12.6 hours for the CABG group (p < 0.0001). RESULTS: Forty-one percent of MIDCABG patients were extubated in the operating room and 59% were discharged home on the first or second postoperative day versus none in the CABG group (p < 0.0001). Significantly less morbidity was observed in the MIDCABG group compared with CABG. Total ratio of cost-to-charge was $12,885 +/- $1,511 for MIDCABG and $21,260 +/- $5,497 for CABG (p < 0.0001), with an average savings of $8,375. CONCLUSIONS: Minimally invasive CABG is associated with significant reduction of resource utilization and morbidity related to inital hospitalization compared with CABG.

Quantitative evaluation of the segmental left ventricular response to dobutamine stress by tissue Doppler echocardiography.

Tissue Doppler imaging displays color-coded myocardial velocity on-line and has potential to objectively quantify regional left ventricular function. Sixty patients, aged 56 +/- 10 years, were studied to determine the normal and abnormal segmental endocardial velocity response to dobutamine stress, and the sensitivity, specificity, and accuracy of tissue Doppler imaging for detecting abnormal wall motion at peak stress as defined by routine visual interpretation. Separate 2-dimensional routine gray scale and color tissue Doppler image sets were acquired at rest and peak dobutamine stress in a digital cineloop format. Routine wall motion interpretation from gray scale images and color-coded peak systolic endocardial velocity from tissue Doppler images were determined independently. Twenty-two patients who reached their target heart rate and had normal wall motion at peak stress served as a control group. There were 19 patients who had wall motion abnormalities at peak stress. Segmental peak endocardial velocities increased significantly in all segments in the control group. Endocardial velocity was significantly lower at peak stress in the pooled abnormal segments than in the pooled normal segments: 3.1 +/- 1.2 versus 7.2 +/- 1.9 cm/s, respectively (p < 0.05 vs normal control). However, the velocity response of abnormal apical segments could not be distinguished from normal controls by tissue Doppler imaging. Excluding apical segments, a peak velocity of < or = 5.5 cm/s with peak stress had an average sensitivity of 96%, specificity of 81%, and accuracy of 86% for identifying abnormal segments at peak stress as defined by routine 2-dimensional criteria. Tissue Doppler imaging has the potential to quantify regional left ventricular function during dobutamine stress.

Color-coded measures of myocardial velocity throughout the cardiac cycle by tissue Doppler imaging to quantify regional left ventricular function.

TDI is a new echocardiographic technique that calculates and displays color-coded myocardial velocity on-line. To determine the feasibility of endocardial velocity throughout the cardiac cycle as a means to quantify regional function, 20 normal subjects aged 30 +/- 5 years and 12 patients with heart disease aged 62 +/- 17 years were studied with a prototype TDI system. TDI M-mode images were acquired by using a multicolored velocity map (display range, -30 to 30 mm/sec; temporal resolution, 90 Hz). Color-coded velocity data were then converted to numeric values off-line at 50 msec intervals. Posterior wall velocities throughout the cardiac cycle by TDI were closely correlated with velocity calculations from the first derivative of routine digitized M-mode tracings (group mean r = 0.88 +/- 0.03, SEE = 7.0 +/- 1.1 mm/sec). Anteroseptal TDI color-coded systolic velocity occurred 164 +/- 84 msec from the onset of the electrocardiographic QRS compared with 203 +/- 33 msec in the posterior wall (P < 0.05) in normal subjects, consistent with normal electrical activation. Significant differences in systolic and diastolic posterior wall TDI velocity data were observed in patients with hypokinetic or akinetic segments assessed by independent routine study when compared with normal controls. Calculated systolic and early diastolic posterior wall TDI indexes correlated significantly with percentage of wall thickening. Of abnormal anteroseptal segments, TDI systolic time velocity integrals were significantly different than normal and correlated with percentage of wall thickening. TDI has potential to quantitatively assess regional left ventricular function.

Mitral annular descent velocity by tissue Doppler echocardiography as an index of global left ventricular function.

Mitral annular descent has been described as an index of left ventricular (LV) systolic function, which is independent of endocardial definition. Echocardiographic tissue Doppler imaging is a new technique that calculates and displays color-coded cardiac tissue velocities on-line. To evaluate mitral annular descent velocity as a rapid index of global LV function, we performed tissue Doppler imaging studies in 55 patients, aged 56 +/-15 years, within 3 hours of radionuclide ventriculographic ejection fraction. Tissue Doppler M-mode studies were obtained from each of 6 mitral annular sites, as follows: inferoseptal and lateral from apical 4-chamber views, anterior and inferior from apical 2-chamber views, and anteroseptal and posterior from apical long-axis views. Only 1 patient with severe mitral annular calcification was excluded. The group mean 6-site average peak mitral annular descent velocity was 5.5 +/- 1.9 cm/s (range 2.4 to 10.5), and the group mean ejection fraction was 49 +/- 18% (range 17 to 80%). The 6-site average peak annular descent velocity correlated linearly with LV ejection fraction (r = 0.86, SEE = 1.02 cm/s): LV ejection fraction = 8.2 (average peak mitral annular descent velocity) + 3%. The 6-site peak mitral annular descent velocity average >5.4 cm/s was 88% sensitive and 97% specific for ejection fraction >50%. The peak mitral annular descent velocity from the apical 4-chamber view (average from inferoseptal and lateral sites) correlated most closely with the LV ejection fraction (r = 0.85) as an individual view. Peak mitral annular descent velocity by tissue Doppler imaging has the potential to estimate rapidly the global LV function.

Primary cardiac lymphoma: echocardiographic characterization and successful resection.

We present a case of primary cardiac lymphoma in a patient with dyspnea and hypoxemia. Transesophageal echocardiography reveals a large right atrial mass and an atrial septal aneurysm with right-to-left shunting through a patent foramen ovale. The patient underwent resection and atrial reconstruction. Pathology was a B cell lymphoma with diffuse large cell histology. There was no evidence of extracardiac involvement, and the patient is well 3 months postoperatively with a normal transthoracic echocardiogram.

Immediate effects of lung transplantation on right ventricular morphology and function in patients with variable degrees of pulmonary hypertension.

OBJECTIVES: This study sought to determine the immediate effects of lung transplantation on right ventricular morphology and function in patients with variable degrees of pulmonary hypertension and to evaluate these features as potential markers of immediate outcome. BACKGROUND: Selected lung transplant recipients with severe preoperative pulmonary hypertension have previously been shown to have a reduction in right ventricular size and improved function at follow-up evaluation. METHODS: Thirty-two consecutive patients (mean [+/- SD] age 44 +/- 11 years) were prospectively classified into three groups according to their pretransplantation pulmonary artery systolic pressure: severe pulmonary hypertensive group > or = 75 mm Hg, intermediate pulmonary hypertensive group 40 to 74 mm Hg and non-pulmonary hypertensive group < 40 mm Hg. Hemodynamic and transesophageal echocardiographic variables were measured immediately before and after lung transplantation. RESULTS: Pulmonary artery systolic and mean pressures markedly decreased after transplantation in the severe pulmonary hypertensive group (from 115 +/- 26 to 45 +/- 19 mm Hg and from 76 +/- 14 to 31 +/- 11 mm Hg, respectively, both p < 0.05). Mean pulmonary artery pressure decreased in the intermediate group (from 34 +/- 7 to 26 +/- 7 mm Hg, p < 0.05). Right ventricular end-diastolic area, end-systolic area and eccentricity index decreased in the severe pulmonary hypertensive group after transplantation. End-diastolic area also decreased in the intermediate pulmonary hypertensive group. Right ventricular fractional area change was not significantly different between groups and did not change consistently after transplantation. Three patients with severe pulmonary hypertension who had continued depression of right ventricular function after transplantation died in the immediate postoperative period. CONCLUSIONS: Lung transplantation is associated with an immediate decrease in pulmonary artery pressures and right ventricular size and normalization of septal geometry but variable changes in right ventricular function. Continued depression of right ventricular fractional area change may be a potential marker of poor outcome.

Acute aortic dissection after blunt chest trauma.

Medial dissection of the aorta after blunt trauma is a rare occurrence. We report the case of a 79-year-old woman injured in a motor vehicle crash who suffered an acute DeBakey type I aortic dissection.

Transesophageal echocardiographic identification of a malpositioned extracorporeal membrane oxygenation cannula.

Transesophageal echocardiography identified malposition of an extracorporeal membrane oxygenation venous cannula across the interatrial septum into the left atrium and the presence of a clot within the cannula's lumen. Transesophageal echocardiography also guided the withdrawal of the cannula into the inferior vena cava.

Transesophageal echocardiography to evaluate patients with severe pulmonary hypertension for lung transplantation.

The surgical approach to lung transplantation for patients with severe pulmonary hypertension will be dependent on the primary disease and specific cardiac anatomy. To determine the safety and utility of transesophageal echocardiography in the management of patients with severe pulmonary hypertension who are being evaluated for lung transplantation, we studied 48 consecutive patients, aged 38 +/- 11 years, with pulmonary artery systolic pressure of 70 mm Hg or greater. All patients previously underwent left and right heart catheterization, transthoracic echocardiography, and radionuclide ventriculography. Transesophageal echocardiography was tolerated well by all patients. Additional data that significantly altered surgical therapy was found in 12 of 48 patients (25%): proximal pulmonary artery thrombi (3), patent foramen ovale with significant right to left shunting (2), atrial septal defect (2), double-outlet right ventricle (2), ventricular septal defect (2), and exclusion of atrial septal defect (1). These findings were confirmed surgically in all patients except 3, who died awaiting transplantation. Transesophageal echocardiography is useful in the evaluation of patients with severe pulmonary hypertension.

Left atrial thrombus after lung transplantation.

We report on a 16-year-old boy who developed a thrombus at the left atrial suture line after undergoing a bilateral sequential single lung transplantation. The diagnosis was made by transesophageal echocardiogram.

Reversible diastolic dysfunction after successful coronary artery bypass surgery. Assessment by transesophageal Doppler echocardiography.

To assess the potential effects of coronary artery bypass surgery on left ventricular diastolic filling, 12 patients, aged 65 +/- 11 years, were studied by serial transesophageal Doppler echocardiograms. Doppler measures of mitral inflow velocity were made before, immediately after, 4 h after, and 20 h after cardiopulmonary bypass (CPB). Left atrial pressure was directly measured and controlled at 10 +/- 2 mm Hg for each study period. Mitral maximal early inflow velocity (E)/maximal atrial velocity (A) ratios and atrial filling fractions were calculated as indexes of diastolic function from maximal E and A velocities and their time velocity integrals, respectively. Data sets were available for serial comparison in 11 patients and were also compared with an age-matched control group of normal values. The results of E/A ratios were as follows: control group--1.4 +/- 0.2; before CPB--1.7 +/- 0.6; immediately after CPB--1.0 +/- 0.2 (p < 0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB--0.8 +/- 0.2 (p < 0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB--1.3 +/- 0.4. Atrial filling fractions were as follows: control group--0.29 +/- 0.05; before CPB--0.25 +/- 0.06; immediately after CPB--0.43 +/- 0.07 (p < 0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB, 0.46 +/- 0.07 (p < 0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB--0.35 +/- 0.06. Alterations in Doppler indexes of left ventricular filling occurred immediately after CPB and persisted 4 h after CPB. These indexes returned to baseline values by 20 h after CPB. This suggests reversible diastolic dysfunction in patients after coronary artery bypass surgery.

Utility and limitations of biplane transesophageal echocardiographic automated border detection for estimation of left ventricular stroke volume and cardiac output.

Recent echocardiographic ABD algorithms can estimate LV volume on-line from a single long-axis plane. The objective of this study was to assess the capability and limitations of transesophageal ABD to estimate stroke volume and cardiac output in patients before and after coronary artery bypass surgery by correlating these data with simultaneous thermodilution measurements. ABD data were acquired on-line from the transverse-plane four-chamber view and the longitudinal-plane two-chamber view and calculated by automated area-length and Simpson's rule formulas for volume. Thirty-three studies were attempted in 18 patients. Technically adequate ABD data were available in all patients from at least one view. Twenty-two (67%) of 33 studies from the four-chamber view and 27 (82%) of 33 studies from the two-chamber view were technically adequate. Cardiac output by all ABD methods was significantly correlated with thermodilution values (r range 0.72 to 0.89; SEE range 0.48 to 0.55 L/min). The two-chamber view underestimated cardiac output slightly, by an average of 0.4 L/min, whereas the four-chamber view consistently underestimated cardiac output by an average of 1.9 L/min. The area-length and Simpson's rule algorithms produced similar results. Biplane transesophageal ABD is an alternative method for estimating cardiac output; the two-chamber view in particular has potential for on-line volume determination.

Infective endocarditis of the pulmonary artery conduit in a recipient with a heterotopic heart transplant: diagnosis by transesophageal echocardiography.

Infective endocarditis is a rare complication after heterotopic heart transplantation. Infection involving the pulmonary artery conduit has not previously been reported. This report describes the diagnosis of this condition by multiplane transesophageal echocardiography.

Transgastric continuous-wave Doppler to determine cardiac output.

A new method to measure cardiac output using transgastric continuous-wave Doppler was evaluated in 31 consecutive patients undergoing cardiac surgery with simultaneous measurement of cardiac output by the thermodilution technique. A 5 MHz single-plane imaging/5 MHz continuous-wave Doppler transesophageal transducer was used to image the left ventricular outflow tract, aortic valve and ascending aorta from a modified transgastric short-axis plane. The continuous-wave Doppler cursor was aligned parallel with blood flow across the aortic valve to obtain the maximal Doppler velocity spectra. Stroke volume was obtained by multiplying the mean Doppler flow velocity integral by the aortic annulus area, which was calculated from its diameter measured from the esophageal 5-chamber view. The stroke volume was multiplied by heart rate to yield cardiac output. A total of 57 simultaneous thermodilution and Doppler studies were attempted. Doppler data were technically limited for 2 patients both before and after cardiopulmonary bypass and for 3 patients before cardiopulmonary bypass with a result of 50 adequate studies of 57 (88%) attempted. The Doppler-derived cardiac outputs were correlated with the simultaneous measurements of cardiac output by the thermodilution technique. Linear regression analysis revealed a close correlation with R = 0.91, SEE = 0.8 liter/min, and y = 1.01x + 0.2 (p < 0.001). In conclusion, transgastric continuous-wave Doppler across the aortic valve is a promising new technique that may be used in selected patients for accurate measurement of cardiac output.