Role of echocardiography in the treatment of cardiac tamponade.

Accumulation of fluid within the pericardial sac results in elevation of intrapericardial pressure with consequent cardiac compression or tamponade. Cardiac tamponade is a life-threatening condition which requires urgent evacuation of pericardial effusion (PE). Current pericardial evacuation techniques and approaches are varied. Echocardiography provides valuable insights into identifying patients who are suitable candidates and further facilitates pericardiocentesis by improving guidance techniques. Several previous publications have provided excellent reviews of the pathophysiology of cardiac tamponade. We review the clinical presentation and role of echocardiography for diagnosis of tamponade. We focus on medical and surgical approaches for the removal of PE. Moreover, as the clinical and hemodynamic consequences of PE depend on the volume and the rate of accumulation of PE, we review the various scenarios of "small" PE resulting in cardiac tamponade.

"Hands-Free" continuous echocardiography during treadmill exercise using a novel ultrasound transducer.

BACKGROUND: Echocardiographic imaging using a handheld transducer in conjunction with treadmill exercise testing is commonly used for the diagnosis of coronary artery disease. Motion of the hand and the transducer during peak exercise preclude optimal imaging. To circumvent the limitations of handheld transducers, we developed a low profile transducer (CONTISON) which can be attached to the chest wall for continuous cardiac imaging. METHODS AND RESULTS: This feasibility study was performed in 10 normal male subjects (28 to 36 years). The ultrasound transducer was placed in the third or fourth intercostal space at the left sternal border to permit imaging of the left ventricle in its short axis. The transducer was interfaced with a commercially available ultrasound machine. The left ventricle was imaged at rest and while subjects exercised according to a standard Bruce protocol. All segments of the left ventricular short axis were seen at rest and peak exercise. Increased left ventricular wall thickening and wall motion were seen at peak exercise. There were no complications from the procedure. CONCLUSION: We demonstrated the feasibility of hands-free left ventricular imaging during treadmill exercise using the CONTISON transducer. Further evaluation of the technique to detect stress-induced wall motion abnormalities, as a means of diagnosing myocardial ischemia, appears warranted. (ECHOCARDIOGRAPHY 2010;27:563-566).

Malignant lymphoma: cardiac involvement at initial presentation.

Malignant lymphoma rarely involves the heart at initial presentation. We have cared for nine cases in the past 8 years. The median age was 45 years (range, 27 to 68). Initial presenting symptoms included chest pain in four, gastrointestinal (GI) symptoms in three, and constitutional "B" symptoms in two. Echocardiography was the most useful noninvasive procedure, and was abnormal in the eight cases studied. Echocardiographic findings included pericardial effusion in six, and mass lesions within the heart in five. Morphologically, the lymphoma was high-grade small noncleaved in four, immunoblastic sarcoma in one, and diffuse large-cell type in four. Clinical staging workup revealed widely disseminated disease in seven. In spite of multiagent chemotherapy, survival was short (median, 1.5 months). Interestingly, four of these patients were homosexual or bisexual men, who fulfill the criteria for acquired immune deficiency syndrome (AIDS).

Renal vasodilatory effect of endothelial stimulation in patients with chronic congestive heart failure.

OBJECTIVES: This study sought to examine the vasodilatory response of the renal circulation to endothelial stimulation in patients with chronic heart failure. BACKGROUND: Renal blood flow is often reduced in patients with chronic congestive heart failure and may lead to deterioration of renal function. Stimulation of renal endothelium has been shown to cause renal vasodilation in animals and in isolated human renal artery. The vasoregulatory role of the renal endothelium in patients with heart failure has not been evaluated. METHODS: Renal vasodilatory effect of endothelial stimulation with acetylcholine was assessed and compared with that of endothelial independent vasodilation with nitroglycerin. Both drugs were infused into the main renal artery. Renal artery cross-sectional area was measured with intravascular ultrasound and renal blood flow velocity with the aid of an intravascular Doppler technique. RESULTS: Both drugs caused a significant and comparable increase in renal artery cross-sectional area (maximal increase [mean +/- SE] 14 +/- 5% with acetylcholine, 15 +/- 5% with nitroglycerin; both changes < 0.05 vs. baseline). Acetylcholine also caused a significant reduction in renal vascular resistance (maximal reduction 55+/- 6%) and increase in renal blood flow (maximal increase 136 +/- 54%). In contrast, nitroglycerin administration showed no significant effect on renal vascular resistance and blood flow. CONCLUSIONS: Stimulation of endothelium-derived nitric oxide with acetylcholine results in a significant vasodilatory effect on both conductance and resistance renal blood vessels and leads to a marked reduction in renal vascular resistance and enhancement of renal blood blow. Nitroglycerin, an exogenous nitric oxide donor, caused a selective vasodilatory effect on renal conductance but not on resistance blood vessels and failed to increase renal blood flow. These data suggest the possibility that stimulation of endogenous nitric oxide production in the kidney could be used as a therapeutic target for enhancement of renal flow in patients with heart failure.

Mitral valve prolapse: association with bizarre behavior, a confusional state, and aphasia.

A 30-year-old man was admitted to the hospital with a history of sudden onset of bizarre behavior and difficulty in speaking that initially was attributed to drug intoxication. Examination disclosed a confused young man with receptive and expressive aphasia. A late systolic murmur was heard in the mitral area and echocardiography confirmed the presence of mitral valve prolapse. A computed tomographic scan of the head and cerebral angiography showed abnormalities consistent with an infarct of the left temporo-occipital region. Since no other predisposing factors were present, this patient's stroke was probably related to mitral valve prolapse.

Transmural myocardial infarction with the prolapsing mitral-leaflet syndrome and normal coronary arteries.

Clinical and electrocardiographic evidence of transmural myocardial infarction developed in two patients (a woman, age 38, and a boy, age 17) with prolapsing mitral-leaflet syndrome. Both had normal coronary angiograms and normal plasma lipid levels. Left ventricular angiography showed dyskinetic areas in both patients. Coronary artery embolism or prolonged coronary artery spasm may have been the underlying mechanism of production of myocardial infarction.

Effects of acebutolol and propranolol on left ventricular performance assessed by echocardiography.

To assess the effects of acebutolol and propranolol on resting left ventricular function, 21 patients with coronary artery disease were studied. A baseline echocardiogram was obtained on day 1, and in a double-blind, randomized, crossover study the patients received 40 mg propranolo every 8 hr for 1 wk, 300 mg acebutolol every 8 hr for 1 wk, and 1 capsule placebo every 8 hr for 1 wk. On days 8, 15, and 22, after an echocardiogram at 7:30 A.M. (i.e., 7.5 hr after the midnight dose), they received double-blind randomized, crossover medications (acebutolol 300 mg, propranolol 40 mg, or placebo). The echocardiogram was repeated at 1.2, and 4 hr after placebo or propranolol and at 2, 3, and 5 hr after acebutolol. The left ventricular end diastolic dimension, left ventricular end systolic dimension, percent systolic shortening of the left ventricular minor axis, and ejection fraction were determined. We found that there was no significant difference between control values for any of the above parameters and those obtained at 1, 2, 4, or 7.5 hr after propranolol or placebo and at 2, 3, 5, or 7.5 hr after acebutolol. We conclude that in the doses used, acebutolol and propranolol do not induce depression of resting left ventricular function in patients with coronary artery disease who have normal or near normal left ventricular function at rest.

Detection of acute myocarditis using nuclear magnetic resonance imaging.

The clinical features, echocardiographic characteristics, and electrocardiographic findings in two patients with acute myocarditis are presented. The first patient had rheumatic myocarditis and the other had probable viral myocarditis. Both patients had regional wall motion abnormalities on the echocardiogram, and the nuclear magnetic resonance image for each patient showed myocardial edema in the area of the wall motion abnormality. These changes disappeared with resolution of the acute disease process. These preliminary data indicate that nuclear magnetic resonance imaging may show myocardial edema in acute myocarditis.

Echocardiographic demonstration of pulmonary embolism as it evolves through the right heart chambers.

In three patients with pulmonary embolism, two-dimensional echocardiography demonstrated thrombi within the right heart chambers. These thrombi, suspected of embolizing into the pulmonary circulation, showed varied morphology and mobility. Of the two patients undergoing embolectomy, only one survived. The third patient improved with anticoagulation therapy. Two-dimensional echocardiography is useful in evaluating patients suspected of having pulmonary thromboembolism because it may demonstrate evolution of the thrombus.

Two-dimensional echocardiographic demonstration of restoration of normal wall motion after acute myocardial infarction.

Left ventricular wall motion was assessed by 2-dimensional (2-D) echocardiography in 17 patients admitted with a first transmural acute myocardial infarction (AMI). The left ventricular myocardium was divided into 17 segments and wall motion was scored from 1 (dyskinesia) to 6 (hyperkinesia) in each segment. Reproducibility of the wall motion scoring system when assessed separately by 2 observers was 89% and when assessed by the same observer at different times, 91%. Seven patients had anterior and 10 inferior wall AMI on the electrocardiogram. Abnormal wall motion was present in 7.3 +/- 2.8 segments (mean +/- standard deviation) on the initial 2-D echocardiogram. On follow-up echocardiograms wall motion was unchanged in 7 patients. In 5 wall motion improved by at least 2 in 2 or more contiguous segments. In 5 other patients wall motion returned to normal in all segments that had shown an abnormality on the initial echocardiogram. These 5 patients (group A), compared with the 12 patients in whom wall motion did not return to normal in all segments (group B), showed fewer involved segments (5.4 +/- 1.7 vs 8 +/- 2.8) and a higher total wall motion score (76 +/- 4 vs 63 +/- 7) (p less than 0.05) on the initial echocardiogram. Duration from the time of the AMI to return of normal wall motion in group A varied from 2 to 8 weeks. Thus, wall motion abnormalities seen on 2-D echocardiography after transmural AMI often improve and wall motion returns to normal in some patients.

Differentiation between acute and healed myocardial infarction by signal averaging and color encoding two-dimensional echocardiography.

To evaluate the ability of a system developed in our laboratory to differentiate between acute and healed myocardial infarction (MI), gated 2-dimensional echocardiography was performed in 10 patients with recent MI (within 48 hours) and 10 patients with healed MI (later than 4 weeks). The 2-dimensional echocardiographic images were digitized using a Datacube VG-120 videoframe digitizer and each digitized videoframe (320 X 240 matrix) was transmitted using a high-speed serial data link to a second computer and stored on floppy disc. Five gated video frames of each patient were time-averaged to give a smoothed digitized image. This image was displayed on high-resolution color monitor connected to a color graphic subsystem. Sixty-four colors indicated pixel intensity. The exact pixel value at any given location was determined using a high-resolution light pen. Color or pixel values were not significantly different between the area of acute MI (pixel intensity 23 +/- 3, mean +/- standard deviation) identified by a regional wall motion abnormality, and the adjacent normal muscle (23 +/- 4). In each patient with healed MI, an increase in color intensity and pixel value (43 +/- 6) was seen in the area of MI (i.e., area of regional wall motion abnormality) compared with adjacent normal muscle (23 +/- 2) (p less than 0.001). These preliminary data in selected patients indicate that this technique enables differentiation between acute and healed MI. It could be of value in management of patients with suspected MI.

Visualization and measurement of flow velocity and flow reserve in aortocoronary saphenous vein bypass grafts by transesophageal echocardiography.

Transesophageal echocardiography was used to image bypass grafts and measure flow reserve in these conduits. Imaging and measurement of flow reserve were feasible in most patients.

Transesophageal assessment of coronary flow velocity reserve during "regular" and "high"-dose dipyridamole stress testing.

To assess the effect of regular and high-dose dipyridamole on coronary flow velocity in the left anterior descending artery (LAD), and to determine whether assessment of coronary flow velocity reserve (CFVR) is more sensitive for detection of ischemia than standard echocardiographic criteria, 47 patients were studied prospectively: 16 patients with stenosis of the LAD, 18 patients with angiographically normal LADs, and 13 patients with minimal disease. Patients underwent transesophageal echocardiographic study of wall motion and LAD flow velocity at baseline and at hyperemia, and for angina and electrocardiographic changes. The mean CFVR values after 0.56 mg/kg after 0.84 mg/kg of dipyridamole were similar: 2.52 +/- 0.87 versus 2.62 +/- 0.90. A CFVR <2.3 (normals mean -2 SDs) was more sensitive (88% at both doses) for the detection of underlying coronary obstruction than was wall motion monitoring (44% and 75%, respectively). The combination of CFVR <2.3 and wall monitoring was more sensitive than index alone (94% at both 0.56 and 0.84 mg/kg). The rate-pressure product was not significantly different at the two doses of dipyridamole. When flow response is the end point of stress testing, as with transesophageal monitoring, the 0.56 mg/kg dose of dipyrid mole is adequate, but when ischemia is the end point (as with wall motion monitoring by 2-dimensional echocardiography), the dose of 0.84 mg/kg is more sensitive.

Application of 2-dimensional contrast studies during pericardiocentesis.

Two-dimensional echocardiographic contrast studies were performed in 16 patients with pericardial effusion. A 4-chamber view was obtained by positioning the transducer at the apex. The exploratory needle was visualized in 9 patients. Five milliliters of saline solution were injected through the exploring needle and a cloud of echoes indicated its position. Microbubbles were seen in all 16 patients. This technique enabled the operator to identify that the needle was inadvertently in the left ventricle in 2 patients and in the right ventricle in 1. Furthermore, in 2 patients, when fluid could not be aspirated, the contrast study confirmed that the needle was in the pericardial sac; in both cases, pericardial fluid could be aspirated with slight manipulation of the needle. In a patient with a stab wound a negative contrast effect indicated the probable site of laceration. Thus, 2-dimensional contrast echocardiography was useful in locating needle position, which facilitated pericardiocentesis.

Determination of cardiac output by transcutaneous continuous-wave ultrasonic Doppler computer.

To evaluate the accuracy of a new, portable, continuous-wave Doppler computer (Ultracom) in measuring cardiac output (CO), simultaneous thermodilution CO and Doppler CO were measured in triplicate in 39 selected patients. Technically adequate Doppler CO studies were obtained in 36 patients. Aortic root diameter was measured by echocardiography and the cross-sectional area was calculated. A continuous-wave Doppler transducer was placed in the suprasternal notch, directed toward the ascending aorta and angled until the maximal velocity signal was achieved. The systolic velocity integral was computed using fast Fourier transform technique. The Doppler CO was computed from the equation: CO = aortic cross-sectional area X systolic velocity integral X heart rate. Interobserver and intraobserver variability studies were also performed. CO measured by thermodilution ranged from 1.86 to 10.1 liters/min (mean 5.26 +/- 1.91 [+/- standard deviation]) and CO by the Doppler method ranged from 1.63 to 10.9 liters/min (mean 5.32 +/- 1.83). The correlation coefficient was 0.97 (p less than 0.001) and standard error of the estimate was 0.42. The regression equation showed that Doppler CO = 0.408 + 0.93 X thermodilution CO. The correlation in 29 volunteers for interobserver variability was 0.98 (p less than 0.001) and in 18 volunteers for intraobserver variability was 0.97 (p less than 0.001). Thus, CO can be determined accurately in many patients using this Doppler technique by trained and experienced persons; intra- and interobserver variability is small.

Accuracy of determination of changes in cardiac output by transcutaneous continuous-wave Doppler computer.

The value of a previously validated portable, continuous-wave Doppler computer was assessed for measuring changes in cardiac output (CO). Simultaneous thermodilution and Doppler CO values were measured in triplicate in 16 patients undergoing clinical intervention with vasodilator therapy. A continuous-wave Doppler transducer was placed in the suprasternal notch and directed toward the ascending aorta and angled until the maximal velocity signal was obtained. The correlation coefficient was 0.92 (standard error of the estimate [SEE] = 0.48 liter/min) at rest; with intervention it was 0.88 (SEE = 0.52 liter/min). Our data indicate that the Doppler computer technique, when used in selected patients, is reliable in detecting changes in CO after vasodilator therapy. It may be of value in clinical situations in which hemodynamic monitoring is impractical.

Identification of the increased frequency of cardiovascular abnormalities associated with mitral valve prolapse by two-dimensional echocardiography.

Two-dimensional echocardiography (2-D echo) was performed in 86 consecutive patients with mitral valve prolapse (MVP) and in 25 normal subjects. In normal subjects, mitral leaflet thickness was 3.5 +/- 0.8 mm (mean +/- standard deviation) and the mitral leaflet thickness to aortic wall thickness ratio was 1.0 +/- 0.2. Patients with MVP were separated into 2 groups: those with normal mitral thickness (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 5.1 mm) and normal mitral thickness to aortic wall thickness ratio (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 1.4) (group I) and others in whom these values were increased (group II). In group I, mitral thickness was 3.6 +/- 0.6 mm and mitral thickness to aortic wall thickness ratio was 1.1 +/- 0.1, and in group II, mitral thickness was 8.8 +/- 1.2 mm and mitral thickness to aortic wall thickness ratio was 2.2 +/- 0.5. The only significant cardiovascular abnormalities in group I were mitral regurgitation in 2 patients and tricuspid valve prolapse in 1 patient. In group II, 7 patients had clinically significant mitral regurgitation, 8 had aortic root abnormalities, 4 had tricuspid valve prolapse and 6 had Marfan's syndrome. Cardiovascular abnormalities were present in 60% (18 of 30) of patients in group II and in 6% (3 of 56) of patients in group I (p less than 0.001). Two-dimensional echo enabled the identification of a subset of patients with MVP who had thickened mitral leaflets. These patients had an increased incidence of cardiovascular abnormalities.

Comparison of Doppler echocardiographic and hemodynamic indexes of left ventricular diastolic properties in coronary artery disease.

Transmitral flow velocity was measured by Doppler echocardiography in 15 patients with coronary artery disease simultaneously with high-fidelity recording of left ventricular pressure. Doppler echocardiographic recordings were also performed in 14 age- and heart rate-matched normal subjects. Statistically significant differences (p less than 0.05) in acceleration half-time (55.3 +/- 8.2 vs 70.4 +/- 14.9 ms), deceleration half-time (83.1 +/- 17.9 vs 109.5 +/- 18.1 ms), deceleration rate (4.9 +/- 0.9 vs 3.1 +/- 0.9 m/s2), peak velocity of early diastolic left ventricular inflow (E wave) (0.78 +/- 0.13 vs 0.61 +/- 0.13 m/s) and A/E ratio (0.74 +/- 0.20 vs 0.98 +/- 0.31) between normal subjects and patients were noted. There was no significant difference in peak velocity of atrial systolic flow (A wave) between normal subjects and patients. Correlation between transmitral flow indexes and hemodynamic indexes of left ventricular diastolic properties were poor, with r values ranging from 0.02 to 0.65. Significant correlations between deceleration rate versus maximal isovolumic left ventricular pressure decrease (maximum -dP/dt) and A wave versus maximum -dP/dt (p less than 0.05) were found (0.53 and 0.65, respectively). Deceleration rate was the most sensitive index of isovolumic relaxation assessed by hemodynamic methods, whereas the A/E ratio was a poor indicator of hemodynamic measurements of isovolumic relaxation. An abnormal deceleration rate had 100% specificity for detecting abnormal maximum -dP/dt, while abnormal acceleration half-time, deceleration half-time and A/E ratio had 80% specificity for detecting abnormal time constant. The deceleration rate, acceleration half-time, deceleration half-time and A/E ratio had a predictive value of 60 to 100% for the detection of abnormal maximum -dP/dt and time constant.

Noninvasive measurement of cardiac output during surgery using a new continuous-wave Doppler esophageal probe.

The ability of a new continuous-wave Doppler esophageal probe to measure cardiac output noninvasively during surgery under general anesthesia was tested and compared with simultaneously measured thermodilution cardiac output. A Doppler computer, calibrated for the aortic diameter and the transcutaneously measured cardiac output from the suprasternal notch, computed the Doppler cardiac output from the descending aortic blood flow velocity signal. A total of 246 paired Doppler cardiac output and thermodilution cardiac output measurements were made in 14 patients during surgery. The average thermodilution cardiac output was 5.90 +/- 3.27 (standard deviation) liters/min (range 1.20 to 19.18); the average Doppler cardiac output was 6.21 +/- 4.0 liters/min (range 2.30 to 28.20). The difference between the cardiac output measured by the 2 techniques was 1.38 +/- 2.2 liters/min (range 0.04 to 16.8). Two to 5 cardiac output measurements were averaged and arranged into "time periods." The average standard deviations for thermodilution and Doppler cardiac outputs within each time period were 0.64 and 0.47 liters/min, respectively. There was a correlation between the 2 measurements over a range of cardiac output values (r = 0.76, Doppler cardiac output = 0.93 x thermodilution cardiac output +0.7, standard error of the estimate = 1.76). Reproducible measurements of Doppler cardiac output were obtained during intraobserver (mean difference 0.64 +/- 0.52 liter/min) and interobserver (mean difference 0.41 +/- 0.36 liter/min) studies (n = 8). Cardiac output measurement by the Doppler esophageal probe could be used for hemodynamic monitoring during surgery in selected patients with cardiopulmonary disease.

Usefulness of the response of flow velocity in the left anterior descending coronary artery to the cold pressor test for evaluating endothelium-dependent vascular relaxation in the coronary microvasculature by transesophageal echocardiography in subjects with angiographically normal coronary arteries.

Measurement of flow velocity in the left anterior descending coronary artery by transesophageal echocardiography in subjects without risk factors for coronary artery disease (group 1) and in subjects with normal coronary arteries but conditions associated with endothelial dysfunction (group 2) revealed that there was a significantly impaired coronary flow velocity response to the cold pressor test in group 2 subjects. Thus, transesophageal echocardiography provides a minimally invasive tool for the functional assessment of endothelium and can be valuable in evaluating endothelial dysfunction and recovery in a variety of disease states.