Contrast echocardiography

Contrast echocardiografie is onderzoek waarbij gebruik gemaakt wordt van een ingespoten stof die andere akoestische eigenschappen heeft dan bloed om de bloedstroom op het beeldscherm zichtbaar te maken. Bijna alle intraveneuze inspuitingen bevatten zeer kleine hoeveelheden lucht en kunnen dus als echo contrast middel gebruikt worden. Kleine hoeveelheden steriel koolzuur kunnen aan de oplossing worden toegevoegd en verhogen het echo contrast effect. Zeer kleine gasbellen passeren gewoonlijk niet door capillairen. Dit gebeurt wel wanneer men in de pulmonale "wedge" positie inspuit zodat zij in de linker kant van het hart aankomen. Het mechanisme van deze transmissie van gasbellen werd onderzocht in dierexperimenteel onderzoek met behulp van verschillende agentia. Er zijn veel belangrijke klinische vraagstellingen waarbij contrast echocardiografie nuttige informatie kan geven: structuur identificatie, het aantonen of uitsiuiten van intracardiale of intrapulmonale rechts-links shunts, de diagnose van congenitale hartziekten, en de diagnose van tricuspidalls insufficientie. Wij hebben aangetoond dat postoperatieve shunts nog aanwezig kunnen zijn lang na succesvolle sluiting van interatriale communicaties. De toekomstmogelijkheden voor contrast echocardiografie zijn indrukwekkend. Theoretisch is het mogelijk dat de graad van doorstroming van het myocard, het hartminuutvo!ume, de grootte van een shunt, en zelfs de intracardiale druk gemeten kunnen worden met behulp van speciaal ontworpen microbellen

Videodensitometric processing of contrast two-dimensional echocardiographic data

We developed a computer program to analyze videodensity changes due to contrast appearance within a given operator-designated rectangle using two-dimensional echocardiograms previously recorded on videotape. Videodensity curves have been obtained from two-dimensional echocardiographic recordings in 14 patients after a total of 32 injections of 5% dextrose solution into the left ventricle during cardiac catheterization. The resulting videodensity vs time curves have some characteristics of indicator-dilution curves. The decay phase of these curves is largely mono-exponential. Potential clinical applications of this technique in measurement of ejection fraction, cardiac output and shunt quantification are discussed, as well as some potential limitations

Cardiac catheterization under echocardiographic control in a pregnant woman

A 22 year old woman had signs of rheumatic mitral and aortic valve disease early in pregnancy. Cardiac catheterization was performed during her third month of pregnancy under two-dimensional echocardiographic control without the use of ionizing radiation. Severe mitral stenosis with mild aortic stenosis was found. Five cubic centimeters of 5 percent dextrose in water were injected by hand to obtain left ventriculograms and supravalvular aortograms of sufficient quality to diagnose valvular regurgitation. The use of "echo-catheterization" may have significant advantages in selected clinical situations

Transmission of ultrasonic contrast through the lungs

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Intravenous carbon dioxide as an echocardiographic contrast agent

Intravenous carbon dioxide (CO2) was employed to cause echocardiographic contrast in 40 patients. One to 3 cc of medically pure CO2 were agitated with 5 to 8 cc of 5% dextrose in water and rapidly injected into an upper extremity vein. Contrast was obtained in all patients. In 33 patients contrast density from 5% dextrose was compared with that from 5% dextrose-CO2 injections. Six of these patients had no contrast on the initial 5% dextrose injection and definite contrast with the subsequent injection containing CO2. Of the 33, 12 patients had initial contrast with 5% dextrose injections and greater contrast density when CO2 was added; 15 showed no definite difference; and none had less contrast with intravenous CO2-5% dextrose than with 5% dextrose alone. Intravenous CO2-5% dextrose is a useful method of increasing contrast in those patients who fail to demonstrate echocardiographic contrast when routine techniques are employed. It is also safe, provided precautions emphasized in this paper are observed

Contrast echocardiographic shunts may persist after atrial septal defect repair

We performed contrast echocardiography on 19 subjects who were asymptomatic in the postoperative period after surgical repair of atrial septal defects. Eighteen of these subjects had adequate right heart echocardiographic contrast to assess the presence or absence of right-to-left shunting. Multiple M-mode and two-dimensional echocardiographic views were studied during several contrast injections with and without the Valsalva manoeuvre. Six patients had postoperative shunts and 12 patients had no postoperative shunts. The age of the six patients with postoperative shunts was 26 +/- 10 years (mean +/- s.d.) and that of the 12 patients without postoperative shunts was 39 +/- 14 years. Four out of six of the postoperative shunt group were males and of these three had patch repairs compared with two males out of 12 with patch repair in the no shunt group. There were no definite differences between the two groups in the following variables: type of atrial septal defect (primum v. secundum), preoperative shunt size, pre-operative peak right ventricular pressure, pre-operative New York Heart Association functional class, pre- or postoperative right ventricular or left ventricular dimensions, aortic and left atrial dimensions. Four of the six patients with postoperative contrast echo shunting underwent cardiac catheterization, showing no significant step-up in oxygen saturation in three, and a significant shunt in one patient who had patch dehiscence at re-operation. We conclude that right-to-left shunts as demonstrated by contrast echocardiography are common in the late postoperative period after atrial septal defect repair. They need not indicate unsuccessful repair or a haemodynamically important residual shunt

Pulmonary wedge injections yielding left-sided echocardiographic contrast

Ultrasound contrast on the left side of the heart without the need for left heart catheterisation was achieved by hand injections of 8 to 10 ml 5 per cent dextrose solution through a catheter in the pulmonary wedge position. Injections were performed in 18 patients undergoing routine cardiac catheterisation and M-mode or two-dimensional echocardiography was used. An adequate wedge position was attained in 17 of the 18 patients. Nine had injections through Cournand catheters, three through Swan-Ganz catheters, and five through both. In 11 of these 17 patients left atrial or left ventricular echocardiographic contrast was seen immediately after wedge injection. Two patients showed diminished or absent contrast on later injections from the same position. Better results were obtained with the Cournand catheter (11/15 positive) than with the Swan-Ganz (1/8 positive) catheter. Pulmonary artery injections proximal to the wedge position did not cause left-sided contrast. No complications were observed. The safety of this method remains to be determined

Sequential intracoronary streptokinase and transluminal angioplasty in unstable angina with evolving myocardial infarction

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