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Discusses the application of infrared thermography in the study of hemangiomas of children. Characteristics of the disease; Capacity of hemangiomas to modify skin temperature; Classifications of hemangiomas.

Objective: To determine normal Doppler and 2D gradients and flow characteristics of the Freestyle stentless aortic bioprosthesis related to valve size., Background: The Freestyle stentless aortic bioprosthesis is one of the newer aortic xenografts. Only limited data are available of the echocardiographic flow characteristics during a mid-term follow-up period of this valve. Therefore valve performance related to valve size was measured during a follow-up period of two years., Methods: 175 consecutive patients with a Freestyle aortic bioprosthesis underwent an echocardiographic and Doppler examination according to a common protocol. Investigations were done within 4 weeks after operation, after 3 to 6 months, and after 1 and 2 years., Results: With a valve size from 19 to 27 mm mean gradients decreased from 8.0 +/- 5.1 mmHg at discharge to 5.8 +/- 3.8 mmHg after 3-6 months (p < 0.001). Thereafter gradients remained stable. The performance index, the ratio of the measured effective orifice area in the patient divided by the effective orifice area measured in vitro increased from 69 +/- 20% at discharge to 79 +/- 29% after one, two and three years. Performance index was especially very high in the smaller sized valves with a performance index of 85 +/- 17% for the 21 mm valve. During follow-up mean gradients remained below 10 mmHg even in the 21 mm valve., Conclusion: Stentless xenografts have ideal haemodynamics, even in the small aortic root.

Background and Aims of the Study: In preceding studies, we reported that abnormal Doppler signals of high intensity (HITS) were frequently found in the cerebral arteries of patients with prosthetic mechanical heart valves. These signals should be attributed either to air microbubbles, possibly due to cavitations or to solid emboli elements. On the other hand, the presence of abnormal intracardiac echoes has been reported in patients with mechanical valves. These echoes should be also attributed to air microbubbles or to formed elements. Although in vitro experiments are in favor of the first explanation, the discussion of their origin remains open., Methods: Among patients subjected to a transesophageal echocardiography (TEE), we selected subjects with mechanical prosthetic heart valves, according to the following criteria: (i) normally functioning valves; (ii) bright echoes suggesting microbubbles, inside the prosthetic valve and/or upstream from it (left ventricular outflow tract or left atrium); (iii) no morphological lesions that could generate solid microemboli at the prosthetic level; (iv) normal carotid arteries, as investigated by color echo-Doppler., Results: Twenty patients were selected: 11 men and nine women of age range 40-64 years. They were implanted with mechanical heart valves (24 Saint-Jude Medical, three Björk-Shiley and one CarboMedics) in the mitral position (10), aortic position (two), or mitral and aortic position (eight) for periods ranging from 10 days to 17 years. There was no major left ventricular dysfunction (mean end-diastolic diameter 51.8 mm; mean ejection fraction 59%). The mean diameter of the left atrium was 46.1 mm. All but three patients were in sinus rhythm; seven had presented with a transient ischemic attack or amaurosis within the six months preceding the investigation. Immediately after TEE, Doppler signals were recorded on the middle cerebral arteries (MCA) during 10 minutes on each side, and the abnormal Doppler signals were counted. Seventeen subjects (85%) exhibited HITS repetition rate from 0.2 to 5.5 per min., Conclusion: The percentage of patients with HITS in a non-selected group with mechanical heart valves was about 50%, as observed in previous studies. It appears that in a selected group of patients the percentage with HITS is consistently higher. Therefore, HITS and abnormal intracardiac echoes could have a common origin.

The authors describe the case of a patient referred for evaluation of multiinfarct dementia. Conventional echocardiography revealed an aneurysm of the interatrial septum. A transesophageal echocardiogram demonstrated superimposed thrombus. This rare cause of systemic emboli can be diagnosed only by transesophageal echocardiography and is of major interest to avoid recurrence of ischemic strokes.

Fifty-eight consecutive elderly patients (seven men and 51 women, mean age 84 +/- 6) admitted for congestive heart failure were prospectively investigated by doppler echocardiography in order to 1) define the prevalence of cardiac failure with normal left ventricular systolic function, 2) estimate the role of abnormalities of left ventricular filling (diastolic dysfunction), 3) evaluate echodoppler parameters for assessment of diastolic function: ratio of early peak on atrial peak of filling velocities (E/A), mitral deceleration time (MDT) and isovolumic relaxation time (IRT). Of the 58 patients, 32 (55%) had normal left ventricular systolic function and 26 (45%) had systolic dysfunction. Of the 32 patients with normal systolic function, diastolic function could not be evaluated in nine patients, was abnormal in 16 and normal in seven. Congestive heart failure with normal systolic function is very frequent in the elderly subject. Sensitivity of clinical data being too low, doppler echocardiography is the easiest noninvasive technique for defining abnormalities of both left ventricular systolic and diastolic function. In the elderly, MDT and IRT are more sensitive parameters than E/A for the diagnosis of diastolic dysfunction.

It is now well recognized that a disorder of left ventricular filling can be sufficient to account for congestive heart failure. Furthermore, evaluation of heart disease would not be complete if it did not include assessment of left ventricular filling, improvement of which probably ensures better control of the heart disease. An efficient and reliable tool for the study of diastolic function is therefore essential. The authors review the current state of knowledge and the more recent developments in Doppler echocardiography in the evaluation of left ventricular diastolic function. After revising the pathophysiology, the methods of studying ventricular filling are described. The recording technique is described, taking into account recent developments in transthoracic and transoesophageal approaches. This investigation provides parameters allowing semiquantitative estimation of filling pressures (mean left atrial pressure, end-diastolic pressure) and reliable evaluation of overall diastolic performance.

Ischemic cerebrovascular accidents are classically attributed to an embolism of cardiac origin in 15% of cases. This longstanding concept is questioned by trans-esophageal echocardiography (TEE). The incidence of anomalies which could be the origin of a cerebral embolism involves more than 50% of cases in certain series. The superiority of TEE over trans-thoracic echocardiography (TTE) emerges in particular when certain abnormalities such as an intra-atrial thrombus, spontaneous atrial contrast, an intra-aortic atherosclerotic plaque, a patent foramen ovale or an aneurysm of the inter-atrial septum are sought. The high incidence of such abnormalities in a population having sustained an ischemic cerebrovascular accident is not sufficient to establish a cause-and-effect relationship between the abnormality and the cerebral event. Certain abnormalities are commonly associated with each other or with emboligenic arrhythmias (atrial fibrillation). Studies hence remain required to determine the respective responsibilities of these various abnormalities and stratify their embolic risk by defining certain risk factors. While awaiting the result of such studies, it would seem valid to suggest the more routine use of TEE in the investigation of ischemic cerebrovascular accidents in young patients free of clinically obvious heart disease, and this regardless of the result of TTE.

The intracardiac hemodynamic responses to short periods of 70 degrees head-down and head-up tilts were studied in 12 normal male subjects, ages 19-24 years. Echo-Doppler techniques were used to measure the transmitral and transaortic flow velocities as well as cardiac index, and to evaluate the peripheral impedance. Head-down tilt (HDT) rapidly induced an increase (9.7%, p < 0.05) in the early passive filling of the left ventricle (ME peak of the transmitral flow velocity curve) and in transaortic flow velocity (8%, p < 0.05), as well as in cardiac output (6%, p < 0.05). In spite of a peripheral vasodilation, the blood pressure increased (7%, p < 0.05 for the systolic; 15%, p < 0.01 for the diastolic) and remained at a high level for the 5 min of the experiment. Head-up tilt (HUT) induced inverse responses; i.e., a large initial decrease in the transmitral (-15%, p < 0.05) and transaortic (-16%, p < 0.001) flows. The shape of the arterial peripheral flow indicated an increased vascular impedance. After a short drop, the blood pressure rapidly recovered a level statistically close to that of the pretest. In both cases, tachycardia occurred. We conclude that, in man, the cardiac responses to the changes in posture appear to be related more to the passive changes in ventricular filling due to the blood shift than to the nervous regulation by the arterial baroreflexes, whereas these reflexes mainly act in the control of the vascular impedance.

Doppler echocardiography has been shown to be an accurate method of assessing left ventricular outflow obstruction in hypertrophic cardiomyopathy (HCM). One of the characteristics of this pressure gradient is its variability and, therefore, we measured this parameter during dynamic exercise testing in 33 patients. The results were compared with those recorded during isoproterenol infusion, the reference stress test for patients with HCM. Submaximal exercise in the recumbent position is usually well tolerated and resulted in a 43% increase in heart rate and a 47% increase in pressure gradient. There was a significant correlation between resting and exercise outflow obstruction (r = 0.90; p = 0.001). Moreover, exercise echo revealed obstruction in 26% of patients without resting pressure gradients (latent obstruction). The interpretation of results obtained with isoproterenol infusion is more difficult: this test resulted in an important increase in the left ventricular pressure gradient (231%) and "revealed" obstruction in 84% of cases. Therefore, we believe that exercise is more physiological and better tolerated than isoproterenol stress infusion and should be adopted as the investigation of choice in HCM even without obstruction at rest. If it is not possible to perform the exercise or no outflow tract obstruction can be demonstrated, an isoproterenol infusion may be used but this is not always well tolerated and the results should be interpreted with caution.

It has been suggested that a thermal countercurrent exchange may occur in the cerebral vascular bed of humans, thereby creating for the brain a state of relative thermal independence with regard to the rest of the body. However, worrying questions have arisen concerning this suggestion. Experiments were carried out on seven young male volunteers. Hyper- and hypothermic conditions were produced by immersion in water at 38.5 degrees C and 25 degrees C, respectively. During the last few minutes of immersion, the face was cooled or warmed by ventilation with a 200 l.min-1 air flow at 5 degrees C or 40 degrees C, respectively. Internal and peripheral temperatures were recorded. Blood flow in the anastomotic vessels between face and brain was measured by Doppler techniques associated with computerized frequency analysis. The general responses were as classically described, i.e. an increase in peripheral and central temperatures during immersion in the warm bath and a decrease in these variables in the cold bath. The reactions produced by cooling or warming the face were small and easily explained by the direct changes of the heat load they induced. Whatever the thermal conditions, the blood flow in the anastomotic vessels between the vascular bed of the face and that of the brain was never reversed. It was concluded that there was no experimental evidence for an efficient thermal counter-current exchange in the vascular bed of the human head.

Measuring blood flow in arteriovenous fistulae in patients under chronic dialysis is of interest to evaluate the repercussions of the fistula on the heart. The apparently simplest method is direct measurement of the mean blood flow velocity by the pulsed doppler technique and ot the cross-section area by ultrasonography, the product of these two values being the blood flow rate. Another method has been proposed, which consists of measuring the cardiac output before and after compression of the fistula, the difference between the two values being supposed to represent the blood flow rate in the fistula. A comparative study of these two methods was conducted in 17 patients aged from 2 to 21 years (mean: 14 years). The direct method gave a figure of 475 ml.min-1.m-2 (SD = 240), while the figure obtained with the indirect method was 471 ml.min-1.m-2 (SD = 227); the difference was statistically not significant. In terms of concept, however, the indirect method is open to much more severe criticism than the direct method, and whenever possible the latter should be preferred when measuring blood flow in arteriovenous fistulae.

The blood flow rate in the supra-hepatic veins has been measured by Doppler ultrasound in 11 subjects suffering from more or less advanced constrictive pericarditis; the results were compared to those obtained with normal subjects. In all the pathological cases, the flow rate curve shows the following modifications: a slight decrease in the X peak, which is related to the blood "demand" caused by the decrease in the ventricular volume during the ejection, and a correlative increase in the Y peak, contemporaneous of the ventricular filling up. In the patients in which the pericarditis has not reached a marked stage of constriction, the intra-thoracic ventilatory pressure variations still exert a certain influence on the supra-hepatic blood flow rate; on the other hand, this influence is suppressed when the constriction is complete. These phenomena are parallel to the pressure modifications observed by catheterism and to those of the mitral and tricuspid transvalvular flow. The advantage of measuring the blood flow rate in the supra-hepatic veins lies in the fact that the access, for ultrasound analysis, to these vessels is quicker and more constant than to the heart valves. This method seems therefore to be an interesting one to assess the stage of development of the constricting pericarditis.

The effects of dehydration prior to heat exposure on sweating and body temperature were tested in 8 men and 8 women, dehydration being 1.3 and 1.0% of body weight, respectively. The subjects were exposed to 40 degrees C for 60 min. Compared with controls (C), in the dehydrated men (D) there was a longer delay in the onset of sweating (C, 7.8, D, 11.6 min, p less than 0.05), a lower total sweat loss (C, 153, D, 127 g X m-2 X h-1, p less than 0.001), and a greater increase in Tre (C, 0.31, D, 0.43 degree C, p less than 0.002). In women, dehydration did not influence the control time course of sweating significantly, nor were these significant body temperature increases during heat exposure. Delay in the onset of sweating in women (C, 18.1, D, 18.7 min) was generally longer than in men (C, 7.8, D, 11.6 min), [F(1,14) = 7.41, p less than 0.05]. A significant correlation was found between the inertia time of sweating and delta Tre in both control and dehydration conditions in the men (r = 0.81, p less than 0.01). The rectal temperature increases in men were also related to the inertia time of electrical skin resistance (r = 0.83, p less than 0.01). It is concluded that dehydration affects sweating and body temperature in men more severely than in women.

Echocardiography has contributed to the exploration of the heart by providing much information, and it has even given rise to new semiological concepts. However, abnormalities of intracardial blood flow, notably shunts and regurgitations, could only be diagnosed indirectly from their effects on cardiac cavities. A new step forward was the advent of pulsed and continuous doppler ultrasound, since from that moment it has been possible to demonstrate abnormal blood flows, to measure their velocity and to determine, albeit with some reservation, such crucial values as pressure gradients. Yet even when these two techniques were combined in the doppler-echotomography systems blind areas persisted, and a blood flow of strongly abnormal direction could in fact escape doppler velocimetry. This is where another development came to the rescue, for it enabled both normal and abnormal flows to be visualized in colours. Owing to this visualization, and provided all possible projections are used, it has become exceptional to "miss" an abnormal blood flow. The diagnosis is now easier and more accurate, and in a second stage the flow can be quantified by pulsed or continuous doppler ultrasound. The colour-coded doppler technique therefore has not superseded the previous one: one may say that it has merely increased diagnostic reliability, but is this not a decisive improvement?