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Biomedical subjects

F J Wackers

Publications and source records attributed to F J Wackers.

At least 109 records · Page 6Linked to original sources
PubMed1985

Use of the initial electrocardiogram to predict in-hospital complications of acute myocardial infarction.

We evaluated the initial electrocardiogram as a predictor of complications in 469 patients with suspected acute myocardial infarction. An electrocardiogram was classified as positive if it showed one or more of the following: evidence of infarction, ischemia, or strain; left ventricular hypertrophy; left bundle-branch block; or paced rhythm. Forty-two (14 per cent) of 302 patients with positive electrocardiograms had at least one life-threatening complication (ventricular fibrillation, sustained ventricular tachycardia, or heart block), as compared with 1 (0.6 per cent) of 167 patients with a negative electrocardiogram. Life-threatening complications were therefore 23 times more likely if the initial electrocardiogram was positive (P less than 0.001). Other complications were 3 to 10 times more likely (P less than 0.01), interventions were 4 to 10 times more likely (P less than 0.05), and death was 17 times more likely (P less than 0.001) in patients with a positive electrocardiogram. We conclude that patients with a negative initial electrocardiogram have a low likelihood of complications and could be admitted to an intermediate care unit instead of a coronary care unit. This would reduce admissions to the coronary care unit by 36 per cent and thereby save considerable hospital costs without compromising patient care.

Connecticut↗
PubMed1985

Quantitative planar thallium-201 stress scintigraphy: a critical evaluation of the method.

The results of quantitative analysis of planar thallium-201 stress scintigraphy are superior to those of visual analysis. The increased sensitivity for detection of coronary artery disease is associated with maintenance of specificity. Consequently, we believe that quantitative analysis is the state-of-the-art for planar 201Tl stress scintigraphy. We emphasize that for reliable and reproducible results, rigorous quality control and strict adherence to a standardized imaging protocol are necessary. An important feature is clarity of display of computer data. In our experience, the most important feature for making quantitative analysis reliable and accessible for a broader user market is simultaneous display of the lower limits of normal with processed patient data. This provides a simple visual impression of the degree and extent of abnormal 201Tl distribution and kinetics relative to the lower limit of normal.

Coronary Disease↗
PubMed1985

Prognostic significance of normal quantitative planar thallium-201 stress scintigraphy in patients with chest pain.

The prognostic significance of normal quantitative planar thallium-201 stress scintigraphy was evaluated in patients with a chest pain syndrome. The prevalence of cardiac events during follow-up was related to the pretest (that is, before stress scintigraphy) likelihood of coronary artery disease determined on the basis of symptoms, age, sex and stress electrocardiography. In a consecutive series of 344 patients who had adequate thallium-201 stress scintigrams, 95 had unequivocally normal studies by quantitative analysis. The pretest likelihood of coronary artery disease in the 95 patients had a bimodal distribution. During a mean follow-up period of 22 +/- 3 months, no patient died. Three patients (3%) had a cardiac event: two of these patients (pretest likelihood of coronary artery disease 54 and 94%) had a nonfatal myocardial infarction 8 and 22 months, respectively, after stress scintigraphy, and one patient (pretest likelihood 98%) underwent percutaneous transluminal coronary angioplasty 16 months after stress scintigraphy for persisting anginal complaints. Three patients were lost to follow-up; all three had a low pretest likelihood of coronary artery disease. It is concluded that patients with chest pain and normal findings on quantitative thallium-201 scintigraphy have an excellent prognosis. Cardiac events are rare (infarction rate 1% per year) and occur in patients with a moderate to high pretest likelihood of coronary artery disease.

Adult↗
PubMed1984

Pathoanatomic correlates of regional left ventricular wall motion assessed by equilibrium radionuclide angiocardiography: a postmortem correlation.

The pathoanatomic correlates of qualitative assessment of regional wall motion (RWM) on routine equilibrium radionuclide angiocardiography (ERNA) were evaluated in 62 patients who had ERNA within 3 months before they died. Of 51 patients with abnormal RWM, 46 (90%) had gross myocardial lesions at autopsy. Of 11 patients with normal RWM, 9 (82%) had normal myocardium. Complete agreement of RWM with postmortem findings in all left ventricular segments occurred in 32% of the patients. Compared with postmortem findings, abnormal RWM on ERNA overestimated the number of macroscopically abnormal segments in 21% of the patients and underestimated in 47%. Of 372 segments analyzed, the overall sensitivity, specificity and predictive value of abnormal RWM on ERNA for detecting gross myocardial infarction or fibrosis was 73%, 75% and 83%, respectively. There were 35 false-positive segments (9%) (15 patients). In 27 of these segments (77%), severe stenosis of the coronary artery supplying the segment or electrocardiographic left bundle branch block could explain these findings. There were 61 false-negative segments (16%) (30 patients). In 55 of these segments (90%), either nontransmural infarction or masking by severe adjacent asynergy provided a potential explanation. Thus, qualitative analysis of RWM on routine ERNA correlates well with postmortem findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Serial radionuclide assessment of doxorubicin cardiotoxicity in cancer patients with abnormal baseline resting left ventricular performance.

While previous studies have demonstrated that sequential radionuclide angiocardiography allows identification of patients at risk for development of congestive heart failure and prediction of the appropriate time for safe discontinuation of doxorubicin, these studies were based predominantly on patients with normal baseline left ventricular performance. This study addresses the use of doxorubicin in patients with abnormal left ventricular ejection fraction (less than 55%) prior to drug administration. Of 337 patients referred for evaluation of left ventricular performance prior to doxorubicin therapy during a 36-month period, 45 (13%) had abnormal baseline left ventricular performance determined by first-pass radionuclide angiocardiography. Sixteen patients had antecedent cardiovascular disease, and 16 patients had received thoracic radiation, while only four patients had both. Left ventricular ejection fraction in each of these subgroups was comparable. In 7 of 16 patients who only had a baseline determination of left ventricular function, doxorubicin was not administered because of a significant concern for the potential risk of doxorubicin cardiotoxicity. In the group of 29 patients followed sequentially over 3 to 15 months (mean, 6 months), there was no significant difference between baseline and final left ventricular ejection fraction (48 +/- 5 vs 47 +/- 9%, p = NS). Only in the 12 patients who received greater than or equal to 350 mg/m2 cumulative dose was there a small but significant fall in left ventricular ejection fraction (48 +/- 4 vs 43 +/- 8%, p less than 0.05). Only one patient developed congestive heart failure. This study demonstrates that doxorubicin can be administered safely to patients with abnormal baseline left ventricular performance using serial radionuclide studies as a means of monitoring therapy. Guidelines for doxorubicin therapy in these patients have been developed.

Adolescent↗
PubMed1983

Anatomic and prognostic significance of new T-wave inversion in unstable angina.

The significance of the development of new T-wave inversion was studied in 118 consecutive patients with unstable angina. The electrocardiograms during hospitalization in the coronary care unit were analyzed for occurrence of new T-wave inversion greater than or equal to 2 mm and correlated with findings at coronary angiography (73 patients) and at follow-up (112 patients). Twenty-nine patients had anterior T-wave inversion. Of these, 25 patients (86%) had greater than or equal to 70% diameter reduction of the left anterior descending (LAD) artery, compared with 11 (26%) of 42 patients without anterior T-wave inversion (p less than 0.001). The sensitivity of T-wave inversion for significant LAD stenosis was 69%, specificity 89%, and positive predictive value 86%. Two patients had T-wave inversion in the inferior leads. Both patients had significant right coronary artery disease, compared with 18 of 55 patients without inferior T-wave inversion (difference not significant [p = NS]. Seventy-one patients who were treated medically had 16 +/- 9 months' follow-up. Of 26 patients who had T-wave inversion, 10 (38%) had cardiac events, compared with 7 (16%) of the remaining 45 patients without T-wave inversion (p less than 0.05). Forty-one patients who had undergone coronary bypass surgery had 19 +/- 9 months' follow-up. Of 22 patients with T-wave inversion, 4 (18%) had cardiac events, compared with 2 (11%) of the remaining 19 patients without T-wave inversion (p = NS). Thus, development of new T-wave inversion greater than or equal to 2 mm in patients with unstable angina (1) is predictive of significant coronary artery stenosis, and (2) identifies a subgroup with poor prognosis when treated medically.

Angina Pectoris↗
PubMed1983

Gold-195m for serial first pass radionuclide angiocardiography during upright exercise in patients with coronary artery disease.

Sequential first pass radionuclide angiocardiography can be performed in rapid succession using gold-195m because of its low radiation dose and short half-life (30.5 seconds). In 25 patients with known or suspected coronary artery disease, first pass studies with gold-195m were obtained using a computerized multicrystal gamma camera at rest (n = 29), at the end of each 3 minute stage of exercise (n = 25) and immediately after exercise (n = 23). In 13 patients, assessment of left ventricular function during exercise with gold-195m was combined with thallium-201 stress scintigraphy. Left ventricular ejection fraction at rest assessed with technetium-99m and gold-195m correlated well (r = 0.93). In addition, repeat left ventricular ejection fractions at rest with gold-195m correlated closely (r = 0.96). Comparing peak exercise left ventricular ejection fraction with ejection fraction at rest, abnormal left ventricular reserve was found in 20 of 25 patients. Various abnormal patterns of left ventricular ejection fraction response were noted, showing the diagnostic potential of serial exercise angiocardiography. Thallium-201 myocardial images, obtained on a single crystal gamma camera after multiple gold-195m injections, were all of good diagnostic quality and were abnormal in 10 of 13 patients. Thus, multiple high count rate first pass studies can be obtained with gold-195m during and after exercise, allowing serial study of physiologic changes in left ventricular function during exercise. Thallium-201 myocardial imaging can be performed using the same exercise test, providing direct comparison of myocardial function and perfusion.

Adult↗
PubMed1983

Aneurysm of the pulmonary artery as a cause of severe chest pain.

A 35-year-old man came to the emergency room with severe prolonged precordial chest pain. Serial chest roentgenograms obtained over a ten-year period revealed gradual development of marked aneurysmal dilatation of the pulmonary artery. Impending rupture of the artery was feared in spite of the presence of normal pulmonary artery pressure. At surgery, a markedly dilated pulmonary artery without evidence of rupture was found and the size was reduced by aneurysmorrhaphy. Prompt and continued relief of symptoms was achieved thereafter. Severe chest pain can be an initial symptom of pulmonary artery aneurysm in the absence of rupture, such pain arising either from pain receptors in the wall of the pulmonary artery or possibly from pressure on contiguous mediastinal structures.

Adult↗
PubMed1982

Radionuclide angiographic exercise left ventricular performance in chronic aortic regurgitation: relationship to resting echographic ventricular dimensions and systolic wall stress index.

Forty-five patients with chronic aortic regurgitation (AR) underwent first-pass radionuclide angiocardiography (RNA) at rest and during upright bicycle exercise, as well as M-mode echocardiography at rest. Abnormal left ventricular (LV) exercise reserve, defined by the absolute change in ejection fraction (EF), was present in 16 of 45 patients (36%). Seven of ten patients with abnormal resting EF (less than 50%) and three of seven symptomatic patients had normal LV exercise responses. Patients with normal LV exercise reserve by RNA had LV dimensions by echo at end diastole (5.9 +/- 0.2 vs 6.5 +/- 0.3 cm, p = NS) and end systole (3.9 +/- 0.2 vs 4.4 +/- 0.3 cm, p = NS) comparable to those in patients wht abnormal LV exercise reserve. However, the mean corrected LV end-diastolic (LVED) radius/wall thickness ratio was significantly greater in AR patients with abnormal LV exercise reserve than in those with normal LV exercise reserve (395 +/- 15 vs 315 +/- 16, p less than 0.01). There data suggest that resting echocardiographic LV dimensions as well as the corrected echo LVED radius/wall thickness ratio have a variable relationship to RNA LV exercise performance in patients with chronic AR.

Adolescent↗
PubMed1982

Gold- 195m, a new generator-produced short-lived radionuclide for sequential assessment of ventricular performance by first pass radionuclide angiocardiography.

The feasibility of performing rapid sequential first pass radionuclide angiocardiography using a new short-lived radiotracer, gold-195m (195mAu) half-life 30.5 seconds) was evaluated. This radionuclide emits a 262 keV gamma ray and is the daughter of mercury-195 (195mHg) (half-life 41.6 hours). The prototype tabletop 195mHg/195mAu generator produced 20 to 25 mCi of 195mAu in 2 ml of eluate (yield of 40 percent). The breakthrough of 195mHg in the eluate was 0.02 percent of the amount of 195mHg in the generator. The eluate contained 20 microCi of 195mHg per study, resulting in an estimated human radiation dose of 0.007 rad/study to the whole body and 0.34 rad/study to the kidney. Four dogs each had 15 to 20 sequential first pass studies performed with 195mHg at 3 to 10 minute intervals using a computerized multicrystal gamma camera. During the left ventricular phase, 160,000 to 190,000 counts/s were acquired. The end-diastolic left ventricular region of interest contained 3,000 to 6,000 counts (background- and decay-corrected). Multiple reproducible values for left ventricular ejection fraction were obtained during stable conditions. The mean (+/- standard deviation) interstudy variability was 4 +/- 2 percent. During infusion of isoproterenol, rapid increase of left ventricular ejection fraction was demonstrated. Excellent agreement was observed between studies performed with technetium-99m diethylenetriaminepentaacetic acid (99mTc-DTPA) and 195mAu. The mean interstudy difference was 4 +/- 3 percent. Thus, sufficiently high yield and dose are obtained from the 195mHg/195mAu generator for reliable high count rate first pass determination of left ventricular ejection fraction. This new short-lived radiotracer makes possible rapid sequential assessments of ventricular function at greatly reduced patient exposure to radiation.

Angiocardiography↗
PubMed1982

Radionuclide assessment of left ventricular function in patients requiring intraoperative balloon pump assistance.

Twenty-three surviving patients who were weaned from cardiopulmonary bypass with intraaortic balloon pump assistance returned for follow-up radionuclide left ventricular (LV) function and thallium 201 perfusion studies at a mean of 23 +/- 3 months following operation. It was found tat despite profound intraoperative myocardial depression requiring intraaortic balloon assistance, 13 patients had no change (within 10%) in the resting LV ejection fraction compared with the preoperative measurement. Among all 23 patients, there was no difference between mean (+/- standard error of the mean) preoperative and postoperative resting LV ejection fraction (48 +/- 4 vs 46 +/- 4%, p = not significant [NS]). Only 11 patients had perioperative myocardial infarction documented by new Q waves in the electrocardiogram, by elevation of creatine kinase-MB fraction, or by defects on thallium 201 imaging not explained by documented myocardial infarction before operation. Overall, postoperative resting LV ejection fraction was not different from the preoperative value in patients with perioperative myocardial infarction (44 +/- 7 vs 47 +/- 5%, p = NS). Postoperative resting LV ejection fraction rose by greater than 10% compared with preoperative values in 4 patients (3 with aortic valve replacement), remained within the 10% limit in 9 patients, and fell by greater than 10% in 10 patients (7 with perioperative myocardial infarction). Only 4 out of 16 patients studied at follow-up with exercise radionuclide studies demonstrated a normal LV response to exercise (greater than 5% increase in LV ejection fraction). Thus, among survivors requiring intraaortic balloon pump assistance for weaning from cardiopulmonary bypass, LV performance at rest is frequently preserved. In addition, 11 of the 23 patients had evidence of perioperative myocardial infarction, indicating a component of reversible intraoperative LV dysfunction.

Adult↗
PubMed1982

Spontaneous changes in left ventricular function over the first 24 hours of acute myocardial infarction: implications for evaluating early therapeutic interventions.

The spontaneous changes in left ventricular ejection fraction (LVEF) during the first 24 hours of a first transmural infarction were assessed in 34 patients by serial gated cardiac blood pool imaging. Major therapeutic interventions with a view to limit infarct size were not used. Four determinations of LVEF were performed. Study 1 was performed as soon as possible after admission to the hospital. Studies 2 and 3 were performed 2 and 4 hours, respectively, after study 1. Twenty-four patients (70%) had study 1 within 6 hours after the onset of acute chest pain and 10 had it 6-12 hours after the onset of chest pain. Study 4 was performed 24 hours after the onset of chest pain. Compared with study 1, 19 of 34 patients (56%) had spontaneous changes in LVEF in at least one of the subsequent studies, exceeding the expected variability in stable patients. The changes ranged from a 32% increase to 14% absolute decrease. LVEF improved in 11 patients and deteriorated in eight. These spontaneous changes in left ventricular performance indicate that a single assessment of LVEF during the early hours of transmural myocardial infarction may not properly characterize cardiac performance in an individual patient and may not be the most appropriate reference against which to compare subsequent evolution of left ventricular function. These data may have implications for studies of the effects of early therapeutic interventions on LVEF.

Adult↗
PubMed1981

Multigated equilibrium radionuclide angiocardiography: improved detection of left ventricular wall motion abnormalities and aneurysms by the addition of the left lateral view.

The usefulness of adding the left lateral (LLAT) view to the standard anterior and left anterior oblique views in multigated equilibrium radionuclide angiocardiography was assessed in 50 patients. Contrast ventriculography was used as the standard. Receiver operating characteristic (ROC) curve analysis was used to assess results. Recognition of inferior wall motion abnormality and left ventricular aneurysms was improved significantly by the addition of the LLAT view. Sensitivity was improved for inferior wall motion abnormality and for aneurysms; there was no loss of specificity. There was no improvement in recognition of anterior wall and apical regional abnormalities in the absence of aneurysms.

Adult↗
PubMed1981

Imaging the inflammatory response to acute myocardial infarction in man using indium-111-labeled autologous platelets.

The feasibility of imaging the inflammatory response to acute transmural myocardial infarction in man using biologically active indium-111 (111In)-labeled autologous leukocytes was assessed in 36 patients. Indium-111 leukocytes (approximately 500 microCi) were injected i.v. 18-112 hours after the onset of chest pain. Cardiac imaging was performed 24 hours later with a mobile gamma camera. Twenty-one patients had positive images and 15 had negative images. The percent of positive images increased as the interval between infarction and 111In-leukocyte injection shortened; all patients injected within 24 hours of infarction had positive images. Patients with positive images were injected with 111In leukocytes earlier after infarction (mean +/- SEM, 43 +/- 4 vs 63 +/- 7 hours; p less than 0.05) and were younger (53 +/- 2 vs 65 +/- 3 years; p less than 0.05) than those with negative images. Several other parameters that could possibly have affected the imaging results were examined and were not significantly different in patients with positive and negative images. These included peak serum creatine kinase, location of infarction, incidence of pericarditis, use of antiinflammatory drugs (aspirin and indomethacin) or membrane-active antiarrhythmic drugs (lidocaine and procainamide), peripheral leukocyte count and cell labeling efficiency. The function of the labeled cell was similar in patients with positive and negative images. Six patients with acute infarction serving as controls and given free 111In oxine and six patients with stable coronary artery disease given 111In leukocytes all had negative cardiac images.

Acute Disease↗
PubMed1981

Radionuclide assessment of peripheral intravascular capacity: a technique to measure intravascular volume changes in the capacitance circulation in man.

Changes in the capacitance vasculature influence venous return and cardiac performance, so an understanding of the effects of pathophysiologic states on the human capacitance vasculature is necessary to understand integrated cardiovascular function in man. Techniques available to assess the capacitance vasculature in man, however, have limitations. We performed radionuclide imaging of the calf or forearm in 51 patients whose erythrocytes had been labeled in vivo with technetium-99m, basing our approach on the principle that counts from the radiolabeled intravascular space are proportional to blood volume. Two-minute or 15 second count acquisitions were obtained from the calf in 42 patients. Counts obtained at rest demonstrated little variation. With veno-occlusion at 15 and 30 mm Hg, counts increased 8 +/- 1% (+/- SEM) (p less than 0.001) and 28 +/- 2% (p less than 0.001), respectively. After 0.4 mg of sublingual nitroglycerin, counts increased 9 +/- 1% (p less than 0.001). With leg elevation, counts decreased 34 +/- 4% (p less than 0.001). Response patterns were similar with 2-minute and 15-second acquisitions. In nine patients who underwent forearm imaging (2-minute acquisitions), counts increased 14 +/- 2% (p less than 0.001) and 26 +/- 4% (p less than 0.001) at 15- and 30-mm Hg veno-occlusion and 15 +/- 3% (p less than 0.001) after nitroglycerin. Volume displacements, recorded simultaneously with a fluid-filled plethysmograph about the contralateral forearm, correlated linearly in all nine patients. Thus, gamma camera imaging of the radiolabeled peripheral intravascular space provides a quantitative and reliable assessment of peripheral vascular capacity in man. The technique could be used in conjunction with gated cardiac imaging in order to assess the interactions of peripheral vascular capacity and ventricular performance.

Animals↗