Quantitative radionuclide angiocardiography: Detection and quantitation of left to right shunts

In 105 patients detection and quantitation of left to right shunts was performed using quantitative radionuclide angiocardiography. The radionuclide angiocardiograms were acquired and analyzed by a gamma camera interfaced to a digital computer system. Pulmonary to systemic flow ($\text{Qp}\text{Qs}$) ratios were calculated by analysis of pulmonary time-activity histograms using a gamma variate model. All patients were studied with cardiac catheterization, left ventricular angiocardiography and radionuclide angiocardiography. The radionuclide method allowed precise detection and quantitation of left to right shunts with a $\text{Qp}\text{Qs}$ ratio of 1.2 to 3.0. There was good agreement between the $\text{Qp}\text{Qs}$ ratio calculated by oximetry at cardiac catheterization and radionuclide angiocardiography (r = 0.94). The information gathered with this nontraumatic method appears sufficiently reliable to be used in the management of patients.     

Radionuclide angiocardiography in evaluation of patients after repair of transposition of the great arteries

The ability of first pass radionuclide angiocardiography to detect and quantitate residual intracardiac shunts and systemic venous obstruction after repair of transposition of the great arteries was evaluated in 29 children. Information from radionuclide scans was compared with data obtained during cardiac catheterization. Three children had a residual right to left shunt detected with both methods. There was good agreement between radionuclide and catheterization quantitation of left to right shunt in the nine patients with a residual defect, five of whom had significant shunting. Nineteen patients with signs suggesting superior vena caval obstruction were evaluated with both radionuclide and catheterization methods. In eight, complete obstruction was detected with both techniques; in one additional patient, partial obstruction was found on catheterization only. One of six patients evaluated for possible inferior vena caval obstruction was identified with both techniques. In the group as a whole, information obtained with radionuclide angiography correlated well with cardiac catheterization data in evaluation of residual shunts and obstruction to systemic venous return.     

Cardiac rhabdomyoma in a newborn two-dimensional echocardiographic diagnosis

Primary cardiac tumors are quite rare in the newborn period. Prior to surgery, cardiac catheterization and angiocardiography have been performed to confirm the two-dimensional echocardiographic findings. In this report a 2-day-old baby with the clinical impression of severe cyanotic congenital heart disease diagnosed by two-dimensional echocardiography as multiple rhabdomyoma and confirmed by surgery is presented. It is emphasized that two-dimensional echocardiography is a very useful technique for the diagnosis of primary cardiac tumors. By means of this method severely symptomatic newborns may be taken directly to surgery without prior cardiac catheterization, thus minimizing complications.     

Cardiac evaluation of candidates for kidney transplantation: value of exercise radionuclide angiocardiography

In view of the high incidence and mortality of coronary artery disease (CAD) in patients with kidney transplantation, a systematic cardiac evaluation was prospectively performed in 103 uraemic patients eligible for transplantation. After clinical examination, 28 patients with symptoms of CAD or diabetes mellitus were referred directly for coronary angiography, whereas the remaining 75 patients had rest and exercise radionuclide angiocardiography for evaluation of possible asymptomatic CAD. Among them, left ventricular ejection fraction was below 40% at rest or fell during exercise by at least 5 EF% in 12 patients; coronary angiography in nine showed CAD in four and hypertensive heart disease in five. In the remaining 63 (of 75) patients without severe resting left ventricular dysfunction or exercise ischaemia, the follow-up of 28 +/- 7 months revealed no clinical manifestation of CAD. Overall incidence of CAD in symptomatic and asymptomatic patients during a follow-up of 27 months after cardiac evaluation was 20 and 25% in nondiabetic and diabetic candidates for kidney transplantation, respectively (P = n.s.). Thus, clinical examination combined with exercise radionuclide angiocardiography in patients without signs or symptoms of heart disease had a high predictive accuracy for presence or absence of late manifestations of CAD. Exercise radionuclide angiocardiography is therefore a useful method for screening kidney transplantation candidates for asymptomatic CAD.     

Radionuclide quantitation of right-to-left intracardiac shunts in children

A simple, noninvasive method for measurement of right-to-left intracardiac shunts would enhance the management of patients with congenital heart disease. This study describes application of data processing techniques used previously in dye-indicator curves to data recorded during the initial transit of radioactive bolus through the central circulation. Radionuclide angiocardiograms were performed in 20 children, mean age 30 months, immediately after cardiac catheterization for congenital heart disease. The radionuclide data recorded over the carotid artery were used to replace arterial sampling required for dye indicators, and forward triangles were fitted to calculate the right-to-left shunt in an approach similar to that of Wood for indicator-dilution curves. Ten of the children had right-to-left shunts by Fick and radionuclide measurement, and 10 of the children with septal defects had no right-to-left shunt by either technique. Both the radionuclide and Fick measurements correlated well (r = 0.95). Therefore, radionuclide angiocardiographic data may be used for accurate calculation of right-to-left shunts in small children, eliminating the need for arterial sampling.     

Equilibrium (gated) radionuclide ejection fraction measurement in the pressure or volume overloaded right ventricle. Comparison of three methods

Although equilibrium radionuclide angiographic measurement of right ventricular ejection fraction (RVEF) has been validated in patients with coronary artery disease, the accuracy of this technique has not been demonstrated in patients with other cardiac diseases which may result in RV pressure and/or volume overload. The accuracy of three methods of equilibrium radionuclide analysis for measuring RVEF was compared in several subgroups of patients with a variety of cardiac diseases, including congenital and valvular heart disease, cor pulmonale, and cardiomyopathy. It was concluded that RVEF may be accurately derived by equilibrium radionuclide ventriculography in patients with a wide variety of cardiac diseases, including those resulting in RV volume and/or pressure overload. Accuracy varies depending on analysis method and the nature of the hemodynamic derangement.     

Left ventricular function at rest and during exercise in congenital complete heart block: A radionuclide angiographic evaluation

This study evaluates intrinsic cardiac performance during upright exercise in patients with congenital complete heart block. Left ventricular ejection fraction and volume were measured at rest and peak upright exercise with radionuclide angiography in 5 patients aged 11 to 39 years with congenital complete heart block: 4 were in New York Heart Association class I and 1 was in class II. The resting cardiac output was maintained at a normal level by an increase in end-diastolic volume rather than by a decrease in end-systolic volume. The left ventricular ejection fraction was normal at rest in all patients, but an abnormal response to exercise was noted in 3 patients. There was no appreciable change in the end-diastolic volume during exercise. Thus, patients with congenital complete heart block utilize the Starling mechanism to maintain normal resting cardiac output, but the response to exercise is usually abnormal even in the absence of symptoms.     

Impact of 2-Dimensional echocardiography on the management of distressed newborns in whom cardiac disease is suspected

The course and management of 40 consecutive newborns (aged less than 2 weeks) who presented with signs and symptoms of congenital heart disease were reviewed to determine the impact of 2-dimensional (2-D) echocardiography on their subsequent management. Of the 40 patients with congenital heart disease, 60% did not undergo cardiac catheterization. Forty-two percent of the patients who were treated surgically went directly to operation without preoperative cardiac catheterization. Only 40% of the patients with congenital heart disease required cardiac catheterization in the newborn period, and 43% of these procedures were primarily therapeutic (that is, balloon atrial septostomy). In each patient 2-D echocardiography correctly identified the major cardiac malformation and there was good agreement with angiographic, surgical, and autopsy findings. The most commonly overlooked defect was a patent ductus arteriosus. Thus, 2-D echocardiography not only allows diagnosis of congenital heart disease in the newborn but can expedite clinical management. No longer is cardiac catheterization necessarily the primary means for an anatomic diagnosis of congenital cardiac malformations in the newborn.     

Gated radionuclide angiographic evaluation of valve regurgitation

Gated radionuclide angiography is a new noninvasive technique that can be used to calculate the ratio of left and right ventricular stroke volumes. This stroke volume ratio, which must be unity in normal subjects, increases in patients with aortic or mitral regurgitation in direct proportion to the degree of left ventricular volume overload, provided no shunts or regurgitant right heart lesions are present. In 22 patients with aortic or mitral regurgitation there was excellent correlation between the stroke volume ratio determined with gated radionuclide angiography and with standard quantitative catheterization methods (r = 0.79). Measurement of valve regurgitation with this radionuclide method also correlated well with data obtained from semiquantitative aortic root or left ventricular cineangiography (r = 0.72). Twenty-one of the 22 patients with valve regurgitation had an abnormally elevated stroke volume ratio, thereby suggesting that gated radionuclide angiography may be useful in detecting or excluding hemodynamically significant valve regurgitation.     

Radionuclide angiocardiographic assessment of pulmonary vascular reactivity in patients with left to right shunt and pulmonary hypertension

Radionuclide angiocardiography was used to assess pulmonary vascular reactivity in eight patients (nine studies) with a large, relatively unrestrictive intracardiac defect and pulmonary arterial hypertension. Radionuclide angiocardiograms, using technetium-99m pertechnetate, were performed first with the patient breathing room air and then after 10 minutes of breathing a mixture containing 90 percent or more of oxygen. The pulmonary to systemic flow ratios obtained by gamma variate analysis of the radionuclide time-activity curves were compared with those calculated with the Fick principle at the time of cardiac catheterization. There was a good correlation between the two methods both in room air studies (r = 0.88) and in those obtained with 90 percent or more of oxygen (r = 0.94). All six studies (in five patients) with a reactive pulmonary vasculature (judged by a pulmonary vascular resistance at cardiac catheterization of less than 6 units/m2 with oxygen or after tolazoline) had a radionuclide pulmonary to systemic flow ratio of 3.0 or greater with oxygen. The three patients with a nonreactive pulmonary vasculature had a radionuclide pulmonary to systemic flow ratio of 2.3 or less with oxygen, a value that was unchanged from the room air value. These data suggest that radionuclide angiocardiography may be a useful, relatively noninvasive method of assessing pulmonary vascular reactivity in patients with a large, relatively unrestrictive intracardiac defect.     

Assessment of left ventricular performance and myocardial viability using quantitative radioisotope techniques.

The diagnostic value of a combined radionuclide technique was compared with conventional angiocardiographic techniques in 60 patients with coronary artery disease. Quantitative 201Tl myocardial imaging combined with radionuclide angiocardiography using 99mTc-HSA provided a safe and accurate method for the assessment of left ventricular performance. The defects on the 201Tl images correlated with the severity of asynergy seen on the contrast ventriculogram. Static imaging alone distinguished hypokinetic from akinetic or dyskinetic areas. However, using both tracer techniques, akinesis could bedistinguished from dyskinesis. In patients with disturbed left ventricular function, cardiac transit times correlated with haemodynamic changes, and left ventricular ejection fraction was the most sensitive index. Thus, this combined radionuclide approach provides data for the evaluation of overall and regional wall function. A major advantage of this non-invasive auantitative technique is its applicability to the critically ill patient at the bedside.     

Assessment of left ventricular performance and myocardial viability using quantitative radioisotope techniques.

The diagnostic value of a combined radionuclide technique was compared with conventional angiocardiographic techniques in 60 patients with coronary artery disease. Quantitative 201Tl myocardial imaging combined with radionuclide angiocardiography using 99mTc-HSA provided a safe and accurate method for the assessment of left ventricular performance. The defects on the 201Tl images correlated with the severity of asynergy seen on the contrast ventriculogram. Static imaging alone distinguished hypokinetic from akinetic or dyskinetic areas. However, using both tracer techniques, akinesis could bedistinguished from dyskinesis. In patients with disturbed left ventricular function, cardiac transit times correlated with haemodynamic changes, and left ventricular ejection fraction was the most sensitive index. Thus, this combined radionuclide approach provides data for the evaluation of overall and regional wall function. A major advantage of this non-invasive auantitative technique is its applicability to the critically ill patient at the bedside.     

Prediction of left ventricular ejection fraction using simple quantitative clinical information

The left ventricular ejection fraction is useful in characterizing cardiac performance and evaluating prognosis in patients with known or suspected cardiac disease. The purpose of this study was to determine if simple, quantitative clinical information generated as part of a routine patient evaluation could be used to predict ejection fraction determined by radionuclide ventriculography. Multiple regression analysis was used to study a group of 64 patients selected to represent the full range of ejection fraction values. All patients had undergone cardiac catheterization and standard chest radiography in addition to resting and exercise radionuclide ventriculography. Using easily determined clinical variables, a regression formula was developed that predicted the radionuclide ventriculographic ejection fraction (r = 0.73). Plain film heart volume, heart rate, pulse pressure, and thoracic width were highly significant terms in the optimal regression equation. For validation, the formula was applied to a second, independent verification data set composed of 41 cases and revealed similar correlation (r = 0.78). A radionuclide ventriculographic ejection fraction below 40 was identified in the verification data set with a sensitivity of 87 percent and specificity of 83 percent. Use of this method, requiring only direct heart rate, blood pressure, and chest radiographic measurements and simple calculations, may assist physicians in patient management and facilitate the optimal use of more invasive and expensive studies.     

Right ventricular imaging with digital subtraction angiocardiography using intraventricular contrast injection

Angiocardiography is of considerable value in the dimensional analysis of the right ventricular (RV) cavity, but conventional angiocardiography requires large amounts of contrast medium. In this study digital subtraction angiocardiography was applied to biplane RV projections of 25 children with congenital heart disease after direct injection of a small dose of contrast medium. Volume measurements were compared with those obtained by conventional angiocardiography. The amount of contrast medium required was reduced to 30%, flow rate to 57% and ventricular ectopic activity to 60% of that used in conventional angiocardiography, and the degree of radiation exposure was reduced considerably. There was a good correlation for end-diastolic (r = 0.996) and end-systolic volume (r = 0.990) determined with both techniques. Digital subtraction angiography after selective RV injection allows accurate volume measurements of the right ventricle in children with congenital heart disease. The main benefits of this method are reduction of the amount of contrast medium, flow rate during injection, radiation and ventricular ectopic activity.     

Intraoperative transesophageal echocardiography

Transesophageal echocardiography (TEE) is an important tool in the intraoperative management of patients undergoing cardiac surgery as well as high-risk patients undergoing noncardiac procedures. This technique is widely used during valve surgery and particularly valuable during valve repair. Its ability to provide a continuous assessment of ventricular performance and filling is important in patients with coronary disease or ventricular dysfunction. TEE evaluation of the thoracic aorta is useful in the diagnosis and treatment of dissection and the selection of cannulation sites free of atherosclerotic disease. In both adults and children, TEE is used to define intracardiac shunts and more complicated congenital lesions. More specialized applications include monitoring during the surgical treatment of patients with hypertrophic myopathy, pericardial disease, and cardiac masses as well as those undergoing minimally invasive bypass surgery. Currently, the technique is performed by both cardiologists and anesthesiologists. Regardless of medical background, physicians providing this service should have specialized training and experience in the field. This review will discuss current applications of intraoperative TEE and the impact of this technique on patient outcomes.     

Quantitative radionuclide angiocardiography

This study introduces a new method for calculating actual left ventricular volumes and cardiac output from data recorded during a single transit of a radionuclide bolus through the heart, and describes in detail current radionuclide angiocardiography methodology. A group of 64 healthy adults with a wide age range were studied to define the normal range of hemodynamic parameters determined by the technique. The normal radionuclide cardiac index averaged 3.25 ± 0.75 liters/min/m², the end-diastolic volume index was 62 ± 16 ml/m², the stroke volume index was 40 ± 9 ml/m², and the ejection fraction was 0.66 ± 0.07. Radionuclide angiocardiograms were performed in patients undergoing cardiac catheterization to validate the measurements. In 33 patients studied by both techniques on the same day, a close correlation was documented for measurement of ejection fraction (r = 0.89) and end-diastolic volume (r = 0.89). Determination of the linear regression equation for the end-diastolic volumes obtained by the two methods (EDV_cath = 1.26 × EDV_RN ? 7.56) permitted correction of end-diastolic volume and provided an approach for calculation of stroke volume and cardiac output. To validate the method of volumetric cardiac output calculation, 33 simultaneous radionuclide and indocyanine green dye determinations of cardiac output were performed in 18 normal young adults and correlated closely over a range of 4–17 liters/min (r = 0.94). These independent comparisons of radionuclide measurements with two separate methods document that initial transit radionuclide angiocardiography accurately assesses left ventricular function.     

Twenty-five years of progress in the medical treatment of pediatric and congenital heart disease

In the past 25 years there has been a many-fold increase in the prospect that with early recognition and modern treatment the newborn with critical congenital heart disease will reach adult life in a healthy condition, prepared to earn a living and to function as a spouse and as a parent. Advancements in the medical treatment of congenital heart disease may create less public acclaim than may surgical treatment but many purely medical developments provide the basis for achieving ultimate surgical success and, by judicious use of some forms of medical treatment, operation can be avoided altogether. The eight major contributions to patient care that are discussed in this review and the 35 that are simply listed are merely examples of the many developments that have occurred in the past 25 years. These include: 1) the organization of pediatric cardiology and the contribution of volunteer health organizations, 2) continuing medical education aimed at promoting early diagnosis of congenital heart disease and prompt referral to a cardiac center, 3) advances in the technology of cardiac catheterization, 4) Rashkind's balloon atrial septostomy and other catheter manipulative procedures, 5) pharmacologic manipulation of the ductus, 6) beta-adrenergic blockade for control of a variety of problems, including paroxysmal hypoxemic attacks, certain arrhythmias and relief of symptoms in hypertrophic cardiomyopathy, 7) echocardiography, and 8) advances in arrhythmias, electrophysiologic studies and use of pacemakers.     

Percutaneous Valve Interventions in the Adult Congenital Heart Disease Population: Emerging Technologies and Indications

Adult survivors with congenital heart disease are not cured and residual cardiac valve lesions are common and contribute substantially to long-term morbidity. Given the increased risk of reoperations in patients with previous cardiac surgery, percutaneous treatment options have been developed. Initially percutaneous therapies focused on right ventricular outflow tract lesions, but they have now expanded to include mitral and aortic valve interventions. Although some of these procedures, such as balloon valvuloplasty of pulmonary valve stenosis and percutaneous pulmonary valve replacement, have become standard of care, there are many new and evolving technologies that will likely become important treatment strategies over the coming decade. The key for success of these transcatheter valve procedures is the careful evaluation of the patient’s individual anatomy and physiology and a multidisciplinary assessment involving cardiologists specialized in adult congenital heart disease, specialized imagers, cardiac surgeons, and interventionalists. Because many of these percutaneous interventions are relatively new, long-term outcomes are not yet well defined, dictating the need for careful and structured long-term observational studies on outcomes of these novel procedures, which will allow refining the indications of a specific intervention and to improve its technical aspects. The aim of this article is to provide an overview of common valve lesions in the adult congenital heart disease population and to discuss treatment options and strategies with a specific focus on percutaneous options.     

Intensive care of the adult patient with congenital heart disease

Prevalence of congenital heart disease in the adult population has increased out of proportion to that of the pediatric population as survival has improved, and adult congenital heart disease patients make up a growing percentage of pediatric and adult cardiac intensive care unit admissions. These patients often develop complex multiorgan system disease as a result of long-standing altered cardiac physiology, and many require reoperation during adulthood. Practitioners who care for these patients in the cardiac intensive care unit must have a strong working knowledge of the pathophysiology of complex congenital heart disease, and a full team of specialists must be available to assist in the care of these patients. This chapter will review some of the common multiorgan system effects of long-standing congenital heart disease (eg, renal and hepatic dysfunction, coagulation abnormalities, arrhythmias) as well as some of the unique cardiopulmonary physiology of this patient population.     

Evaluation of left ventricular performance and of its reserve by radionuclide angiocardiography: comparison with other methods

This study was performed, i) to compare radionuclide angiocardiography with the other methods, and ii) to evaluate its usefulness in investigating left ventricular performance and its reserve. Radionuclide angiocardiography, chest X-ray film, chest X-ray cinegraphy, echocardiography, two-dimensional echocardiography, pulsed Doppler flowmetry, cardiokymography, myocardial imaging, contrast ventriculography and coronary arteriography were performed (:also at exercise) in 105 subjects including various kinds of cardiac patients. Radionuclide angiocardiography could be performed both at rest and at exercise, contrary to invasive methods. In detailed analysis of left ventricular mechanics in non-ischemic heart disease, echocardiography at rest and at exercise may be appropriate, because of its high image resolution. In evaluation of ischemic heart diseases, radionuclide angiocardiography at rest and at exercise might be appropriate, because of bidirectional informations and its high success rate. Two-dimensional echocardiography with M-mode echocardiography might compensate for it, particularly for continuous informations during exercise. Detection of regional wall motion dysfunction at exercise is more specific than exercise ECG and is more sensitive than exercise myocardial imaging. From many kinds of examinations, appropriate one should be selected according to the purpose of investigators. Much more technical progress in these methods can be expected.