Nontraumatic determination of left ventricular ejection fraction by radionuclide angiocardiography

Cardiovascular function and dysfunction in sickle cell anemia

The 100th anniversary of the discovery of sickle cell anemia (SCA) as a distinct clinical entity by James B. Herrick in 1910 will soon be a reality. SCA continues to present opportunities for elemental observations of basic science and pathophysiologic clinical mechanisms-in particular, those associated with cardiopulmonary and circulatory disorders. Data indicate that cardiomegaly results from increased work caused by the anemia and that myocardial ischemia may result from the combined effects of severe anemia, microthrombi, and increased blood viscosity producing myocardial dysfunction, scarring, and elevated filling pressures. Sudden death has resulted from frank myocardial infarction and ischemia-induced rhythm disturbances. Myocardial injury may also be associated with bone marrow embolism. Mortality risk factors include systemic hypertension, pulmonary hypertension, and possibly subclinical electrical instability.

EANM/ESC guidelines for radionuclide imaging of cardiac function

Radionuclide imaging of cardiac function represents a number of well-validated techniques for accurate determination of right (RV) and left ventricular (LV) ejection fraction (EF) and LV volumes. These first European guidelines give recommendations for how and when to use first-pass and equilibrium radionuclide ventriculography, gated myocardial perfusion scintigraphy, gated PET, and studies with non-imaging devices for the evaluation of cardiac function. The items covered are presented in 11 sections: clinical indications, radiopharmaceuticals and dosimetry, study acquisition, RV EF, LV EF, LV volumes, LV regional function, LV diastolic function, reports and image display and reference values from the literature of RVEF, LVEF and LV volumes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "prevailing or general consensus". The guidelines are designed to assist in the practice of referral to, performance, interpretation and reporting of nuclear cardiology studies for the evaluation of cardiac performance.

Measurement of body venous tone

The venous system contains about 70% of the blood volume, and approximately 75% of the venous volume is in the small veins and venules. Veins play an active role in the control of cardiac output (CO) and blood pressure. Drugs that interfere with venous tone have profound effects on CO and blood pressure due to the large venous capacity. Information on body venous tone cannot be obtained from studies using isolated venous preparations and perfused venous beds, which lack modulating cardiovascular reflex mechanisms. In vivo methods used for the assessment of venous function in experimental animals and humans are as follows: the mean circulatory filling pressure (MCFP) method for the determination of body venous tone, constant CO reservoir technique for measuring vascular compliance and unstressed volume, plethysmography or blood-pool scintigraphy along with venous occlusion for measuring the volume and compliance of an organ, linear variable differential transformer (LVDT) technique for estimating the diameter of a human dorsal hand vein, intravascular ultrasound (IVUS) imaging technique to monitor the cross-sectional area of a large vein, and ultrasonic crystals to estimate the dimension of an organ. These methods are described and critically evaluated to disclose their validity, merits and limitations.

Application of mathematical methods in dynamic nuclear medicine studies

Dynamic nuclear medicine studies can generate large quantities of data, and their analysis consists essentially of a reduction of these data to a small number of relevant parameters which will assist in clinical decision making. This review examines some of the mathematical techniques that have been used in the process of data reduction and attempts to explain the principles behind their application. It particularly identifies the techniques that have stood the test of time and demonstrated their usefulness, many of which are now available as standard tools on nuclear medicine processing computers. These include curve processing tools such as smoothing, fitting and factor analysis, as well as tools based on empirical models, such as the Patlak/Rutland plot and deconvolution. Compartmental models and vascular models are also examined and the review finishes with a summary of some functional images and condensed images. It is concluded that an appreciation of the principles and limitations of these mathematical tools is valuable for their correct usage and interpretation of the results produced.

First-pass radionuclide angiocardiography with single-crystal gamma cameras

Both multicrystal and single-crystal detectors have been in use for more than 25 years for measurement of ejection fraction by analysis of images collected during the first-pass transit of radionuclides through the heart. Originally, multicrystal cameras were preferred, because they provided higher count rates than Anger cameras; however, over the years improvements in count rate capability and collimator design have enabled Anger cameras to perform equally well. This has become an important issue now that readily available 99mTc agents, such as sestamibi, enable evaluation of both myocardial function and perfusion from a single injection. The technical abilities of a particular camera determine which acquisition protocols are most likely to provide clinically useable images for the widest spectrum of patients. Electrocardiographic-gated list mode collection is highly desirable for first-pass imaging, providing the greatest flexibility of data review, rebinning, and analysis. Attention to quality control issues of data characterization and processing is important to ensure accuracy and precision of all measurements. Accurate determinations of ejection fraction of the left ventricle are possible routinely and, under favorable circumstances, of the right ventricle as well.

Bayesian decision making based on measurements containing errors

The paper presents a Bayesian approach to the construction of diagnostic and prognostic algorithms, based on the use of several diagnostic factors (tests) in combination. With this approach, the simultaneous use of dichotomous, discrete, categoric, and continuous factors is easy and the resulting algorithms are more efficient than those of other known methods. Moreover, each factor value that is available for use is assumed to represent an estimate (the result of an imperfect measurement) of some (unknown) true value. The proposed method of accounting for measurement errors is advantageous as regards efficiency for users of the algorithm (physicians) if the accuracy of the factor-measurement techniques at their disposal differs from that of the constructor of the algorithm (the scientist). The approach is illustrated by an example, and possible error models and methods of collecting statistical data are discussed.

Detection of left ventricular dysfunction after acute myocardial infarction: comparison of clinical, echocardiographic, and neurohormonal methods

OBJECTIVE

The SAVE study showed that captopril improves mortality in patients with left ventricular dysfunction after myocardial infarction and that this benefit occurred even in patients with no clinically overt heart failure. On the basis of this, it seems important to identify correctly which patients have left ventricular dysfunction after a myocardial infarction. The objective was to compare various methods of identifying patients with left ventricular dysfunction (left ventricular ejection fraction, LVEF, < or = 40%) after acute myocardial infarction. The methods compared were echocardiography (quantitative and qualitative visual assessment), clinical evaluation (subjective assessment and three clinical score methods), and measurement of plasma concentrations of cardiac natriuretic peptide hormones (atrial and brain natriuretic peptides, ANP and BNP).

DESIGN

Cross sectional study of left ventricular function in patients two to eight days after acute myocardial infarction.

SETTING

Coronary care unit of a teaching hospital.

PATIENTS

75 survivors of a recent myocardial infarction aged 40 to 88 with no history of cardiac failure and without cardiogenic shock at the time of entry to the study.

MAIN OUTCOME MEASURES

Sensitivities and specificities of the various methods of detecting left ventricular dysfunction were calculated by comparing them with a cross sectional echocardiographic algorithm for LVEF.

RESULTS

Clinical impression was poor at identifying LVEF < 40% (sensitivity 46%). Clinical scoring improved this figure somewhat (modified Peel index sensitivity 64%). Qualitative visual assessment echocardiography was a more sensitive method (sensitivity 82%) for detecting LVEF < 40%. Plasma BNP concentration was also a sensitive measure for detecting left ventricular dysfunction (sensitivity 84%) but plasma ANP concentration was much poorer (sensitivity 64%).

CONCLUSION

Left ventricular dysfunction is easily and reliably detected by echocardiographic measurement of LVEF and also by a quick qualitative echocardiographic assessment but is likely to be missed by clinical assessment alone. High concentrations of plasma BNP maybe another useful indicator of left ventricular dysfunction, particularly in hospitals where not all patients can be screened by echocardiography or radionuclide ventriculography after myocardial infarction.

Natural history of left ventricular function in patients with uncomplicated acute myocardial infarction

To investigate the serial changes of the infarcted and the noninfarcted areas, first-pass radionuclide angiocardiography was performed in 16 patients with uncomplicated anterior myocardial infarction (MI) at four weeks, one year, and two years after the onset of MI. Global ejection fraction (EF) and regional EF of the infarcted area improved significantly from four weeks to one year after MI (from 39 +/- 16 to 44 +/- 16 percent, 23 +/- 3 to 29 +/- 5 percent, both p < 0.01), but did not change from one year to two years after MI. Regional EF of the noninfarcted area and left ventricular end-diastolic and end-systolic volume did not change during the study period. There was a significant relation in the direction of the changes of global EF and regional EF of the infarcted area during the first year after MI, whereas no relation was observed between the changes of global EF and regional EF of the noninfarcted area. A greater improvement in regional EF of the infarcted area was observed in seven patients who had spontaneous recanalization compared with nine patients with totally occluded coronary arteries. Thus, a significant improvement in cardiac function, mainly due to the increase in regional EF of the infarcted area, was observed during the first year after MI, which was related to patency of coronary artery.

Histologic evidence of myocardial damage in apparently healthy subjects with ventricular arrhythmias and myocardial dysfunction

The association of ventricular arrhythmias and myocardial dysfunction could be considered an early step toward cardiomyopathy; therefore, we studied 28 patients in NYHA class I and II, characterized by complex ventricular arrhythmias (VA) on 24-h Holter monitoring and volumetric and/or contractile abnormalities on a standard two-dimensional echocardiogram (2-D echo). All patients underwent radioisotopic angiography, 20 patients complete hemodynamic study, and 15 patients endomyocardial biopsy. Ambulatory ECG monitoring showed the presence of frequent premature ventricular contractions in 14 patients (50%) and episodes of ventricular tachycardia in 16 patients (57%). 2-D echo showed mono- or biventricular enlargement and dyssynergies in 25 patients (89%) (left ventricle in 6, right ventricle in 11, both in 8). Two patients showed only left ventricle enlargement and one patient isolated left ventricular dyssynergies. Radioisotopic angiography showed mono- or biventricular ejection fraction reduction in 24 patients (85%) and regional dyssynergies in 24 patients (85%) in accordance with 2-D echo. Hemodynamic study showed in all patients normal coronary arteries, and right and left angiography confirmed enlargement and/or regional dyssynergies. Endomyocardial biopsy was abnormal in 11 of 15 patients: various degrees of hypertrophy, parcellar fibrosis, and adipogenic infiltration were found. Our preliminary data suggest that the simultaneous occurrence of ventricular arrhythmias and ventricular dyssynergies and/or enlargement in patients without apparent clinical heart disease may represent an early stage of dilated cardiomyopathy.

Electrocardiographic tall R waves in the right precordial leads. Comparison of recently proposed ECG and VCG criteria for distinguishing posterolateral myocardial infarction from prominent anterior forces in normal subjects

Electrocardiographic tall R waves in the right precordial leads may be present in patients with posterior myocardial infarction, right ventricular hypertrophy, various conduction disturbances, and some forms of cardiomyopathy and in clinically otherwise normal subjects with prominent anterior electromotive forces. Clinical uncertainty most often arises in distinguishing possible prior posterolateral myocardial infarction (PMI) from the unusual normal variant (PAF). The ECGs and VCGs of 15 subjects with posterolateral infarction were compared with tracings from 12 subjects with no evidence of cardiac disease, all individuals demonstrating tall R waves (R/S greater than 1.0 in V1 and/or V2) in the right precordial leads on surface ECG. By standard ECG, the infarction group was characterized by taller T waves in leads V1 and V2, shorter T waves in V6, greater T2-T6 index, and a more negative two variable function as described by Nestico. By VCG, the infarction group was characterized by a more anteriorly oriented T loop, more leftward maximal frontal plane QRS vector and a lower calculated -45 degrees/ab, as described by Suzuki. An algorithm was proposed that permitted proper classification (PAF vs. PMI) based on ECG criteria in 75% of subjects with 90% accuracy. This compared favorably with performance of the Frank vectorcardiogram, including using more recently proposed criteria. Routine use of the VCG, therefore, in this clinical setting may no longer be justified.

99mTc-MIBI (RP-30) to define the extent of myocardial ischemia and evaluate ventricular function

99mTc-MIBI, a new myocardial perfusion agent, is a technetium labeled isonitrile derivative. We have taken advantage of the physical characteristics of 99mTc to combine at rest, post infarction, ventricular function studies with analysis of perfusion. We have studied at rest and at stress, 22 patients with coronary artery disease selected on the basis of an abnormal coronary angiogram or on the basis of a positive exercise ECG stress test for symptomatic angina. We have also studied, at rest only, 20 patients with a previous myocardial infarction. A comparative thallium planar scintigraphy was obtained for all patients. The sensitivity of 99mTc-MIBI scintigraphy for detecting individual vessel lesions at stress was 88% as compared with 83% for 201Tl. Sensitivity was higher in patients with previous myocardial infarction (93% for the 2 isotopes) than in patients without (85% for 99mTc-MIBI versus 81% for 201Tl). Segmental myocardial correspondence between 99mTc-MIBI and 201Tl was very close (92%). The overall sensitivity for the detection of acute myocardial infarction reached respectively 91% for 99mTc MIBI and 87% for 201Tl. The specificity in the regions corresponding to arteries not involved was excellent for both tracers as we did not observe any false positive result. This is important information but it does not correspond to the specificity to detect coronary artery disease in the overall patient population. The correlation between first pass left ventricular ejection fraction obtained with 99mTc-MIBI and equilibrium left ventricular ejection fraction obtained with 99mTc red cells was excellent (r = 0.96). It was not as good but was still satisfactory for the right ventricle (r = 0.75).(ABSTRACT TRUNCATED AT 250 WORDS)

Technically suboptimal first-pass radionuclide angiographic studies

First-pass radionuclide angiography (FPRNA) has proven to correctly assess left ventricular function, however, technical difficulties do occur. One hundred and thirty one patients had contrast angiography and resting radionuclide angiography within 24 h. Of the 131 patients, 86 (66%) had adequate studies and 45 (34%) were technically suboptimal studies. In the latter group, low counts affected the quality of the images but did not change the left ventricular ejection fraction (LVEF) or regional wall motion (RWM) scores. Patients with high background activity showed overestimation of LVEF, however, by using a formula that was derived from the linear regression the LVEF could be calculated accurately in most cases. Multiple technical problems were noted in 14 patients in whom the best correlation was between contrast LVEF and background uncorrected LVEF from FPRNA (r = 0.87). In the latter group, FPRNA showed overestimation of RWM in 8 patients (57%), mainly in the inferior wall. We conclude that for most technically compromised first-pass radionuclide angiographic data, accurate LVEF values can be achieved but errors in regional wall motion interpretation will occur, especially when multiple technical problems exist.

Doxorubicin cardiotoxicity: response of left ventricular ejection fraction to exercise and incidence of regional wall motion abnormalities

Gated radionuclide ventriculograms were performed to evaluate cardiac function in 53 patients who received doxorubicin treatment for various malignancies (mean dose: 449 +/- 128 mg/m2 BSA). In fourteen patients (Group I) function was evaluated before and after treatment; there was a significant decrease of resting left ventricular ejection fraction after therapy (p less than 0.001). Twenty-two patients (Group II) had serial studies during treatment which also showed a significant fall of resting left ventricular ejection fraction (p less than 0.001). Eighteen patients in Groups I and II had supine exercise studies. A normal exercise response was maintained in the majority of patients. Exercise testing added little to the diagnostic performance when compared to serial resting studies. We found regional wall motion abnormalities (mild apical hypokinesis) at rest by visual inspection in 33 of 36 Group I and Group II patients who had received doxorubicin. In the baseline or initial study, only 4 of these patients demonstrated WMA. In 18 Group I and II patients who were exercised, 3 had wall motion abnormalities during the initial study. All of these patients demonstrated wall motion abnormalities at rest after the second study, however only 7 of 18 demonstrated abnormalities during the exercise study. The results indicate that resting left ventricular ejection fraction declines after doxorubicin treatment. Exercise radionuclide angiography may not increase diagnostic accuracy for the detection of doxorubicin related cardiotoxicity. Regional wall motion abnormalities occur with a relatively high incidence following doxorubicin therapy, more readily detectable at rest. However, the exercise study can distinguish doxorubicin related wall motion abnormalities from those due to coronary artery disease.

Prolonged PR interval associated with an abnormal frontal plane QRS axis as an electrocardiographic criterion of left ventricular function

The aim of this study was to investigate whether, in patients who had had one or more myocardial infarctions, the electrocardiographic appearances of prolonged PR interval associated with an abnormal frontal plane QRS axis are correlated with the value of left ventricular ejection fraction. Seventy-three consecutive patients all of whom had had at least one myocardial infarction, were divided into 3 groups: Group A, 22 patients having on their electrocardiogram a prolonged PR interval and an abnormal frontal plane QRS axis; Group B, 15 patients having an abnormal QRS axis as a solitary conduction disturbance; and Group C, 36 patients without conduction abnormalities. The ejection fraction, determined in all patients by gated blood pool imaging, was found to be 30% +/- 8 (mean +/- 1 SD) in Group A, 53% +/- 21 in Group B, and 52% +/- 14 in Group C (P less than 0.001). An ejection fraction of less than 40% was found in 91% of patients in Group A, in 33.33% in Group B, and in 8.33% in Group C (P less than 0.01). Multiple segment ventricular wall contraction abnormalities were found in 50, 6.66, and 11.11%, respectively (P less than 0.001). It can be presumed, therefore, that in patients after one or more myocardial infarctions, this association of conduction abnormalities signifies a severe impairment of ventricular contractility and may identify a subgroup with a high prevalence of severely depressed ejection fraction.

The reliability of measuring left ventricular ejection fraction by radionuclide cardiography: evaluation by the method of variance components

A statistical model based on the method of variance components was applied to obtain confidence statements for single and repeat determinations of left ventricular ejection fraction by radionuclide techniques. With this approach variance caused by individual factors in the measurement procedure is estimated to allow calculation of confidence intervals based on single measurements and the detection limits for changes. Six study groups made up of a total of 143 subjects were examined by both multigated equilibrium and first pass imaging. Under favourable conditions (with an updated gamma camera and experienced observer) the 95% confidence interval with a single measurement of left ventricular ejection fraction by equilibrium imaging was +/- 3 ejection fraction units, compared with +/- 6 units with the first pass technique (one ejection fraction unit = 1/100 of the possible values from 0.00 to 1.00). The minimal significant changes (at the 5% level) in measured equilibrium left ventricular ejection fraction at intervals of 15 min, 3 days, 1, 3, and 4 weeks were +/- 4, +/- 4, +/- 5, +/- 5, and +/- 6 units, respectively. The corresponding minimal detectable changes in a subject's "true" left ventricular ejection fraction for the same intervals were +/- 7, +/- 7, +/- 10, +/- 10, and +/- 12 units respectively. With first pass imaging, only average values for the variation at repeat determination could be calculated. The minimal significant change in measured first pass left ventricular ejection fraction was +/- 7 units, and the minimal detectable change in "true" left ventricular ejection fraction was +/- 14 units. Measurements of left ventricular ejection fraction by equilibrium technique were generally more reproducible than first pass determinations because the variability caused by study acquisition, observer analysis, and residual errors was smaller. The method of variance components appears to be well suited to the evaluation of quantitative biological measurements in clinical use. The popularity of established procedures may obscure the lack of basic information about method evaluation.

Automatic ventricular edge detection for determination of left ventricular volumes, ejection fraction and regional ejection fractions from first pass radioisotope angiography

An automated method for detection of left ventricular (LV) outline (including the aortic and mitral valve planes) was developed for measurements of end-diastolic volume (EDV), end-systolic volume (ESV), global ejection fraction (EF), and regional EFs from first pass radioisotope ventriculography. The procedure includes: (1) interpolative background subtraction, (2) construction of gradient images, (3) automatic detection of valve planes, and (4) automatic radial search of LV outlines. The correlation between contrast angiography and Tc-99m first pass study was r = 0.84 (SEE = 23.4) for EDV, r = 0.93 (SEE = 12.8) for ESV, r = 0.84 (SEE = 6.91) for EF (via counts) and r = 0.80 (SEE = 8.56) for EF (via area-length method). Tests of intra-observer, inter-observer and inter-study variability revealed low level of variability. The results showed the potential of the automation of data processing for first pass radioisotope ventriculography.

Quantitative radionuclide angiocardiography

Quantitation of cardiac pump function using radionuclide angiocardiography provides objective information for the management of patients with heart disease. Left and right ventricular ejection fraction, stroke volume ratio, ejection rate, diastolic function, ventricular volume, parametric imaging, amplitude and phase analysis, and shunt quantification can be measured from the radionuclide angiocardiogram at rest, during exercise, and during pharmacologic interventions. This review describes these methods and discusses their reliability and their role in the clinical assessment of patients with cardiac disease.

Diltiazem treatment for the management of ischaemia in patients with poor left ventricular function: safety of long term administration

The tendency of oral diltiazem (a calcium entry blocking agent and a negative inotrope) to induce or exacerbate congestive heart failure when used for the long term management of myocardial ischaemia in patients with poor left ventricular function has not been investigated before. Twenty two patients (aged 42-73 years) with pretreatment left ventricular ejection fraction ranging from 0.11 to 0.39 were given open label oral diltiazem (120-360 mg/24 h (mean 254 mg)) for two weeks to 16 months (mean 7.5 months, median 6.2 months). There was a weight change of greater than 3 lb (1.35 kg) in nine patients--five gained weight and four lost it. Diltiazem treatment did not alter the mean (SD) cardiothoracic ratio on chest x ray (0.47 (0.06) before vs 0.48 (0.05) after) or the left ventricular ejection fraction at rest (0.28 (0.09) before vs 0.26 (0.08) after). Diltiazem was discontinued in one patient because of symptoms indicative of worsening congestive heart failure. No patient required admission to hospital for treatment of symptoms resulting from further left ventricular decompensation. Diltiazem was discontinued in six other patients for other reasons. Long term administration of oral diltiazem was not regularly associated with a deterioration in clinical, radiographic, or radionuclide ventriculographic estimates of left ventricular function, even in patients with poor baseline left ventricular systolic performance.

Nuclear ejection fraction measurements with a small crystal detector: methodological investigations

A series of studies were performed with a single crystal detector system, nuclear stethoscope (N.S.) (Bios) used for measuring left ventricular function (ejection fraction [EF]). Counting capacity, validity, reproducibility, effect of repositioning of the instrument and of different operators were investigated. Counting capacity was found to be approximately linear up to a count rate of 40.000 cps. Validity was studied by comparing measurements in the same subject using the N.S. with those obtained by a gamma-camera computer system with software using a background subtraction similar to that in the N.S. The mean difference in EF (0.01) was not significant. Maximum emptying and filling velocity measurements with the two instruments were also compared r = 0.86 and r = 0.89, respectively, and a coefficient of variation of 18.1% and 17.9%. Reproducibility was determined from duplicate determinations under identical conditions. The standard error of a single determination was 5%. Repositioning by the same operator increased the variation to 9.1% without any systematic difference. Comparison between two operators did not increase the coefficient of variation (8.8%). There was a systematic difference between measurements using the two acquisition modes, ventricular function mode and position monitor mode. Beat-to-beat variation of EF values during 12 s in 25 patients with coronary heart disease studied under standardized resting conditions was 11.9%.

Measurement of both left ventricular function and regional myocardial perfusion with 133Xe in dogs

A technique to measure left ventricular (LV) function and myocardial perfusion was validated in 12 dogs. 133Xe in saline was injected into the left atrium (LA) or LV and two data sets were obtained using gamma camera imaging: 1) A first pass gated scan for LV function; followed by 2) Sequential images for regional myocardial perfusion. LV ejection fraction and wall motion measurements from the 133Xe blood pool images were compared to ejection fraction (r = 0.88, P less than 0.01) and wall motion (r = 0.83, P less than 0.01) data from 99mTc labeled blood pool scans. The perfusion measurements obtained with the 133Xe method were compared to microsphere data (r = 0.79, P less than 0.01). Measurements after LV 133Xe injection were similar to data following LA injection. Thus, quantitative assessment of global LV function, regional wall motion and myocardial perfusion is possible with LA or LV 133Xe injection and gamma camera imaging.

Determination of right ventricular ejection fraction in children with cystic fibrosis

The radionuclide right ventricular ejection fraction (RVEF) determined by means of Krypton-81m represents a simple, noninvasive, and accurate procedure to quantify the right ventricular contractility. This procedure was applied to 25 young patients with cystic fibrosis. The RVEF tended to decrease with the progression of the lung disease, as assessed by the clinical S-K score, the degree of the defects on lung scintigraphy, the PaO2, and the lung function tests. However, the decrease of RVEF in patients with marked lung function tests. However, the decrease of RVEF in patients with marked lung involvement was moderate, and terminal lung disease was sometimes associated with normal right heart contractility.

Q wave, S-T segment, and T wave myocardial infarction. Useful clinical distinction

Abundant experimental and clinical evidence now suggests that the presence or absence of Q waves on surface electrocardiography does not permit distinction between pathologic transmural and subendocardial myocardial infarction. It has been recommended, therefore, that use of certain electrocardiographic descriptors of myocardial infarction be avoided. One hundred fourteen consecutive patients with first myocardial infarction were studied. The lack of development of Q waves accompanying acute myocardial infarction delineated a group of patients with low in-hospital mortality. Left ventricular ejection fraction was less after Q wave (0.48 +/- 0.16) than after non-Q wave (0.67 +/- 0.10) infarction (p less than 0.0001). Left ventricular end-diastolic pressure was greater after Q wave (16.1 +/- 5.9 mm Hg) than after non-Q wave (11.7 +/- 2.7 mm Hg) infarction (p less than 0.02). Fixed thallium perfusion scintigraphic defects were more common in survivors of Q wave (98 percent [41 of 42]) than in survivors of non-Q wave (64 percent [seven of 11]) infarction (p less than 0.002). Objectively demonstrable myocardial ischemia was more common after non-Q wave (68 percent [13 of 19]) than after Q wave (32 percent [16 of 50]) infarction (p less than 0.01). The incidence of late cardiac events (sudden death plus reinfarction) did not differ after Q wave or non-Q wave infarction. Q wave, S-T segment, and T wave myocardial infarctions differ physiologically, clinically, and prognostically. It is of little consequence to the clinician managing patients whether such useful electrocardiographic descriptors also accurately define groups that differ anatomically with regard to the thickness of the injured myocardial wall.

Regional myocardial dysfunction in patients with angina at rest and response to isosorbide dinitrate assessed by phase analysis of radionuclide ventriculograms

Left and right ventricular synchrony was assessed in 15 patients with angina at rest but no previous infarction by phase analysis of equilibrium radionuclide ventriculograms. Transient thallium-201 perfusion defects were noted in all during angina at rest and coronary vasospasm was documented in nine of the patients. Radionuclide ventriculograms were performed at control, during the ischemic episodes and after intravenous isosorbide dinitrate. Left and right ventricular phase histograms were quantified by the standard deviation from the mean of the peak (SD). Left ventricular ejection fraction averaged 65 +/- 11% (mean +/- standard deviation) at control, decreased in all patients during angina at rest to 49 +/- 14% (p less than 0.01) and increased in all patients after isosorbide dinitrate to 66 +/- 12%. However, ejection fraction during ischemia was abnormal in only nine patients and changed in two by less than 5% from the control value. Regional wall motion abnormalities were noted in all patients during the ischemic episodes but resolved after isosorbide dinitrate administration. Control left ventricular SD was 14.5 +/- 4 degrees, increased in all patients to 22.8 +/- 5 degrees during angina at rest (p less than 0.01) and returned to control values after isosorbide dinitrate administration (14.2 +/- 4 degrees). In contrast, right ventricular SD did not significantly change during ischemia as compared with control and isosorbide dinitrate. It is concluded that in angina at rest, a normal left ventricular ejection fraction does not exclude severe regional dysfunction; separate left and right ventricular SD is a sensitive index in detecting transient left ventricular dysfunction, and relief of ischemia is associated with rapid normalization of regional left ventricular function.

Radionuclide angiography and endomyocardial biopsy in the assessment of doxorubicin cardiotoxicity

Thirty-eight patients with a mean age of 53.2 years (19 to 75 years of age), who were receiving doxorubicin (D) for malignant disease, were studied in order to determine the relationship between functional and morphologic myocardial changes at different dose levels. Serial patient evaluations included physical examination, chest x-ray, electrocardiogram (ECG), endomyocardial biopsy (EMB), and rest-exercise gated nuclear angiography (GNA), at doses of D ranging from 144 to 954 mg/m2 (mean, 426 mg/m2). Physical examination, chest x-ray, and ECG proved to be insensitive predictors of D cardiotoxicity. Correlation of GNA and EMB in 31 patient evaluations, exclusive of known heart disease, did not reveal any false-positive angiograms, and all abnormal GNAs were associated with abnormal biopsies. Use of stress GNA uncovered six abnormal ventricles which could have been missed with a rest GNA alone. It has been suggested that: (1) GNA is a reliable monitor of D therapy; (2) an exercise study should be performed when the rest ejection fraction is normal, but is unnecessary when the rest EF is abnormal; (3) all patients with a resting ejection fraction of less than 45%, exclusive of other cardiac disease, should have D discontinued; and (4) endomyocardial biopsy is useful in assessing D cardiotoxicity in patients with other possible causes of an abnormal GNA.

Right ventricular and left ventricular ejection fraction in pediatric patients with normal hearts: first-pass radionuclide angiocardiography

First-pass radionuclide angiocardiography was used to estimate right ventricular (RV) ejection fraction (EF) and left ventricular (LV) EF in infants, children, and teenagers with normal hearts. The right ventricle was analyzed in 74 patients and the left ventricle in 72 patients. Mean RVEF for the group was 0.53 +/- 0.06 (range 0.43 to 0.73); mean LVEF for the group was 0.68 +/- 0.09 (range 0.49 to 0.86). Lower values tended to be present in younger patients. However, there was no statistical difference in EFs between age groups and no linear correlation between magnitude of EF and age or EF and heart rate for either ventricle. Data obtained demonstrated that RVEF and LVEF in children with normal hearts are similar to those in adults with normal cardiovascular systems. A RVEF of 0.41 to 0.47 or a LVEF of 0.50 to 0.59 would suggest borderline systolic function; a RVEF less than 0.41 (mean -2 SD) or LVEF less than 0.50 (mean -2 SD) would be considered abnormal when this technique of first-pass radionuclide angiocardiography is used.

Detection of left ventricular dysfunction in ambulatory subjects with the bedside Valsalva maneuver

The bedside sphygmomanometric determination of the arterial pressure response during the Valsalva maneuver was incorporated into the routine physical examination of ambulatory subjects. Four distinct Valsalva responses were noted: ultrasinusoidal, sinusoidal, absent overshoot, and square wave. The absent overshoot response was further divided into positional and constant types--the latter consistently exhibiting this response regardless of body position. Correlation with resting left ventricular ejection fraction was obtained by radionuclide cineangiography in 200 patients, of whom 81 had left ventricular systolic dysfunction (ejection fraction less than 0.50). Significant differences in the mean left ventricular ejection fraction were found in subjects with an ultrasinusoidal response (0.65 +/- 0.11), sinusoidal response (0.55 +/- 0.15), constant absent overshoot response (0.37 +/- 0.18), and square wave response (0.16 +/- 0.04) to Valsalva maneuver. The sensitivity of an abnormal Valsalva response (absent overshoot or square wave responses) for the bedside detection of left ventricular systolic dysfunction was 69 percent, and the predictive value of an ultrasinusoidal Valsalva response for normal ejection fraction was 93 percent. It is concluded that the high predictive accuracy of the Valsalva maneuver makes this simple bedside technique a valuable method for assessing resting left ventricular function.

Pulmonary circulation time: comparison of mean, median, peak, and onset (appearance) values using indocyanine green and first-transit radionuclide techniques

To assess the difference between a variety of mathematical methods for assessing pulmonary transit time, we evaluated 11 acutely anesthetized and instrumented mongrel dogs at a control stage and then during infusions of isoproterenol or phenylephrine, or after the induction of ischemia. Green-dye optical density curves were obtained to evaluate a variety of pulmonary circulation times. Mean transit time, median time, peak time, and onset time all correlated well (r greater than or equal to 0.93), with the mean time being the longest, followed by the median time (4% less than the mean time, p less than 0.05), peak time (15% less than the mean time p less than 0.01), and onset or appearance time (49% less than the mean time, p less than 0.001). In the 34 available data points the mean time averaged 4.67 +/- 1.7 seconds, the median time averaged 4.47 +/- 1.74 seconds, the peak time averaged 3.98 +/- 1.7 seconds, and the onset time averaged 2.27 +/- 1.43 seconds. Similar results were obtained from the first-pass radionuclide angiograms from 17 adult male subjects. We conclude that median, peak, and onset times are reasonable though predictably shorter approximates of mean pulmonary transit time. They may be utilized during interventions (particularly when alternative counting methods are planned, as with radionuclide or possibly digital angiographic techniques) as guides to changes in the pulmonary circulation.

Mitral E point septal separation: a reliable index of left ventricular performance in coronary artery disease

The diagnostic value of E point septal separation (EPSS) was assessed in 108 patients with coronary artery disease who underwent coronary angiography and M-mode echocardiography within a 2-year period at LAC/USC Medical Center. In patients with anterior myocardial infarction, EPSS correlated well with angiographic ejection fraction, with a specificity of 85% and sensitivity of 82%. In inferior myocardial infarction, a 21% frequency of falsely elevated EPSS values was encountered; the sensitivity for detecting reduced ejection fraction was 100% and the specificity was 67%. In combined anterior and inferior myocardial infarction, EPSS accurately estimated abnormal ejection fractions with a sensitivity and specificity of 100%. An abnormal EPSS (more than 7 mm) was found to be more sensitive (87%) and specific (75%) in detecting individuals with angiographically reduced ejection fraction (less than 50%) compared to other echocardiographic indices of pump function. Importantly, EPSS was effective in estimating left ventricular function in the presence of left bundle branch block, paradoxical septal motion, and angiographic septal, posterior, and anterior wall motion abnormalities.

Radionuclide ventriculography to evaluate myocardial function

Developments over the past decade have allowed one to visualize the right and left ventricles using radionuclide techniques and to study the influence of a wide range of physiologic, pharmacologic and surgical interventions on global and regional ventricular function thereby providing important diagnostic insight and improved therapeutic capabilities. These tests are relatively non-invasive, they can be performed serially, they may be performed in patients that are seriously ill, and they have no recognized risk other than low level radiation exposure. With continued improvement in noninvasive imaging and processing and in the sophistication of associated computer systems, one may expect significant and wide ranging additional contributions in the assessment of myocardial function using radionuclide ventriculographic techniques.

Automatic left ventricular outlining

A method for automatically outlining the left ventricle is described. The boundary at any point in the heart cycle is obtained from a convoluted image derived from an ordinary frame of count rate convoluted with a functional image frame scaled in the time of maximum count rate. The position of the pulmonary artery indicates the level of the aortic valve plane.

Clinical assessment and follow-up of functional capacity in patients with chronic congestive cardiomyopathy

The presumption that the results of left ventricular systolic function tests performed at rest are related to the symptoms of chronic congestive heart failure or to exercise capacity is unproved. Thirty-three patients with chronic congestive cardiomyopathy underwent serial exercise tests, determinations of ejection fraction and systolic time intervals, echocardiograms, assessment of symptom score, chest roentgenogram, and physical examination over a mean ( +/- standard deviation) of 24.8 +/- 14.1 months. Maximal exercise performance achieved correlation with symptoms (r = 0.66) but not with indexes of left ventricular function. Edema, elevated jugular venous pressure, rales and radiologic evidence of pulmonary venous hypertension were more common in patients with severe limitation of exercise capacity. in 17 patients whose functional capacity changed during the follow-up period, congruent changes in left ventricular function measured at rest were not consistently observed. Thus the findings on history, physical examination and radiologic examination correlate with exercise capacity, but indexes of left ventricular performance at rest do not and therefore are of limited use in assessing treatment. The clinical course of patients with chronic congestive cardiomyopathy can be followed up safely, effectively and economically by simple clinical observations. Serial laboratory testing of left ventricular function can be reserved for specific indications, research and patients with valvular heart disease.