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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.

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A computerized continuous wave Doppler instrument was used to monitor changes in cardiac output during symptom limited supine bicycle exercise in 41 individuals. Eight (19%) had technically unsatisfactory Doppler signals. Of the remaining 33 patients, 21 had clinical and 18 had angiographic evidence of coronary artery disease (group 1) and 12 age-matched asymptomatic subjects served as controls (group 2). In eight group 1 patients, cardiac output determined simultaneously by Doppler and thermodilution technique correlated well at rest and peak exercise (Y = 1.71x + 0.69, SEE = 0.57, r = 0.86, P less than 0.001). During exercise, group 1 patients increased their cardiac output from 5.2 +/- 1 to 6.9 +/- 1.4 (mean +/- SD), group 2 subjects increased their cardiac output from 5.5 +/- 1.3 to 10.9 +/- 2. Group 1 patients, when compared to group 2 control subjects, had a lesser increase in cardiac output (34% versus 103%, P less than 0.05), a shorter duration of exercise (6.1 versus 9.7 mins, P less than 0.05) and a lower double product (172 +/- 18 versus 211 +/- 27, P less than 0.05). This new Doppler technique provides reasonably accurate estimates of cardiac output at rest and on moderate exercise in selected patients. In selected clinical situations, it may be a valuable addition to other measurements that are usually determined during exercise.

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2-D echocardiography was performed in 50 patients with transmural anteroseptal (group 1) or inferior myocardial infarction (group 2). Twenty-four patients with myocardial infarction had diagnostic coronary arteriography. Twenty-five normal subjects served as controls. The interventricular septum was subdivided into proximal and distal halves. In the parasternal long axis view (PSLAX), interventricular septum asynergy was seen in 96% of patients of group 1 and none in group 2. In the apical four chamber view (A4C), the proximal interventricular septum was abnormal in 48% of group 2 patients, but only one patient in group 1. The distal half of the interventricular septum in the A4C was abnormal in 48% of patients in group 1 and 12% in group 2. Complete asynergy of the interventricular septum in the PSLAX view was seen in 80% of patients with proximal stenosis in the left anterior descending artery (LAD) in association with anteroseptal myocardial infarction. Distal asynergy in this view was noted in all patients with a stenosis distal to the first septal perforator. In conclusion, the PSLAX visualizes the anterior interventricular septum and demonstrates wall motion abnormalities associated with anteroseptal infarction; complete asynergy of the interventricular septum in the PSLAX view suggests an anteroseptal infarction with proximal LAD stenosis; the A4C visualizes the posterior interventricular septum and proximal wall motion abnormalities are seen in inferior infarction while distal septal wall motion abnormalities occur in anteroseptal or inferior infarction.

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A new TSH immunoenzymometric assay was found to be capable of discriminating between the serum TSH values of normal subjects [2.28 +/- 1.02 (+/-SD); range, 0.6-6.5 microU/ml] and those of clinically euthyroid, antithyroid drug-treated (n = 22) or clinically thyrotoxic (n = 34) patients. While a wide spectrum of basal TSH values was found in the antithyroid drug group [ranging from undetectable (less than 0.05 microU/ml: 57%) to 17.9 microU/ml], all clinically thyrotoxic patients had undetectable values. In 33 patients receiving chronic oral T4 therapy for treatment of goiter (n = 15) or thyroid cancer (n = 18), 48% (6 of 33) had undetectable basal TSH levels and no TSH response to TRH stimulation. Detectable TSH levels were found in 42% (14 of 33), and TRH responsiveness was found in 52% (17 of 33). The TSH response to TRH stimulation was less than 2.0 microU/ml in 7 patients. Serum free T4 index, free T3 index, and free T4 levels and oral T4 dosage were inferior predictors of TRH responsiveness compared to the basal TSH value. No patient receiving more than 0.2 mg T4 daily or having a free T4 index above 18, a free T3 index above 205 or a free T4 level above 3.0 ng/dl had a TSH response to TRH. Seventy-six percent (16 of 21) of the patients, when reevaluated 1-6 weeks after increased oral T4 dosage, had a significant reduction in their serum thyroglobulin level. This was true of both patients with initially detectable (11 of 14) as well as undetectable (5 of 7) basal serum TSH levels. These findings support the concept that subnormal and, for that matter, as yet undetectable levels of circulating TSH may exert stimulatory effects on thyroid tissue.

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Seventeen subjects, including 12 mildly obese women, were investigated to determine the presence of a diurnal variation in serum T3 levels. A subset of 8 subjects was studied after fasting for 6 days, while another subset of 5 subjects was studied 2 days after receiving 3 mg T4, orally, to suppress TSH secretion. To negate the influence of hemoconcentration produced by ambulation, serum T3 to T4 ratios (nanograms per microgram) rather than total T3 values were used for analysis. A synchronous diurnal rhythm for mean serum T3 to T4 ratios and TSH values was found, with mean nighttime increases of 7.8% and 49.5%, respectively. The timing of the T3 to T4 and TSH nocturnal peaks for individual subjects, however, were not correlated, suggesting that T3 to T4 ratios changes were not caused by TSH stimulation of thyroid T3 release. During fasting, the diurnal rhythm of serum T3 to T4 was obliterated within 24 h of beginning the fast, although TSH rhythmicity persisted. After the 3-mg oral T4 dose, serum TSH became undetectable, while the diurnal serum T3 to T4 ratio changes persisted. In contrast, there was no detectable diurnal rhythmicity of serum T3 to T4 ratios during either the control or fasting period. We conclude that the diurnal rhythm of serum T3 is not TSH dependent, but, rather, is influenced by some as yet unidentified dietary signal, which alters the efficiency of the peripheral tissue T4 to T3 conversion.

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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.

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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.

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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.

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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.

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Thirty-four patients with clinical infectious endocarditis were examined by M-mode and two-dimensional (2D) echocardiography. Vegetations were identified in 16 patients (47%) by M-mode and in 27 patients (87%) by 2D echocardiography. Vegetations identified by 2D echocardiography were categorized as small (less than 5 mm), medium (5 to 9 mm), or large (greater than or equal to 10 mm). Large vegetations were caused by a variety of organisms, had a higher incidence of surgery (44% v 0%), and had no increased incidence of stroke or death. The larger the vegetation, the more detectable it was by M-mode. Aortic valve vegetations were associated with a higher incidence of congestive heart failure (CHF) (67% v 14%) and stroke (44% v 9%). Four patients with large aortic valve vegetations had the highest complication rate; CHF developed in all four, two had valve replacement, one had a stroke, and two died.

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Recent studies have demonstrated the usefulness of two-dimensional echocardiography in the detection of regional wall abnormalities in acute myocardial infarction. We describe two patients with acute myocarditis who had acute chest pain simulating acute myocardial infarction. Two-dimensional echocardiography initially demonstrated regional wall motion abnormalities that disappeared within a few days. These two cases illustrate that regional wall motion abnormalities are not specific for acute myocardial infarction and that acute myocarditis may simulate acute myocardial infarction.

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Aneurysm of the mitral valve occurs most commonly in association with infective endocarditis of the aortic valve. The probable mechanism of its formation is destruction of the aortic valve which results in a regurgitant jet that strikes the anterior leaflet of the mitral valve, creating a secondary site of infection leading to the development of an aneurysm. Perforation of these aneurysms may occur, resulting in mitral regurgitation and pulmonary edema from a ventricle already volume overloaded from aortic regurgitation. This report describes the clinical and echocardiographic-pathologic findings in five patients with pathologically proven aneurysm of the mitral valve. There are no clinical features that appear specific for this abnormality. The two-dimensional echocardiographic feature that is helpful in the diagnosis is a bulge of the mitral valve leaflet toward the left atrium that persists throughout the cardiac cycle. Preoperative diagnosis is important because a mitral valve aneurysm may produce serious complications and is frequently overlooked during surgery. Repair of the aneurysm may be feasible; otherwise, valve replacement becomes necessary. Careful two-dimensional echocardiographic examination should be done in patients with left-sided infective endocarditis to detect an aneurysm of the mitral valve.

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A 25-year-old woman with chronic neuropsychiatric symptoms, peripheral neuropathy and hypoglycaemia was found to have an islet cell adenoma in the pancreas. Her neuropsychiatric symptoms disappeared following its removal and she partially recovered from her peripheral neuropathy.

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We reviewed the M-mode and two-dimensional echocardiograms of 100 consecutive patients with rheumatic heart disease. All were subsequently studied by cardiac catheterization and angiography. In four patients, cardiac catheterization showed tricuspid stenosis (average mean diastolic gradient 6.2 mm Hg), which was confirmed during cardiac surgery. M-mode echocardiography showed a diminished EF slope in 12 patients (mean 26 mm/sec), including the four patients with tricuspid stenosis. Seven of the eight patients without tricuspid stenosis had significant pulmonary hypertension; the reasons for the diminished EF slope in the other patient could not be identified. Tricuspid stenosis was diagnosed in four patients from two-dimensional echocardiograms on the basis of diastolic doming and restricted leaflet motion of the tricuspid valve. These four patients were the same patients in whom tricuspid stenosis was diagnosed by cardiac catheterization. We conclude that two-dimensional echocardiography is useful in the diagnosis of tricuspid stenosis.

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Out-patient medical clinics in Sri Lanka often have long queues of patients waiting to see a doctor partly due to a shortage of doctors. To apply operational research techniques to optimize the functioning of the clinic, an initial step is to determine the distributional pattern of patient arrival times and the doctors' service times. The results showed that the arrival times of patients were time dependent. However, analysis of half-hourly data of inter-arrival times showed a negative exponential distribution. The doctor's service time varied from doctor to doctor and whether new or follow up patients were being seen. Each of the service times seemed to fit into an Erlangian distribution.

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