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Biomedical subjects

V Kalff

Publications and source records attributed to V Kalff.

At least 37 records · Page 2Linked to original sources
PubMed1988

Longitudinal study of ventricular function after the Mustard operation for transposition of the great arteries: a long term follow up.

An earlier study of 25 patients who were investigated by radionuclide angiography after a Mustard procedure showed that they had had evidence of right and left ventricular dysfunction at rest and with exercise. Twenty one (mean age 17.0 years (range 13.7-20.6) 11 female patients) of the original 25 patients were followed up a mean of 4.3 years later (mean 14.6 years (range 12.5-16.0) after the procedure). The group means for resting right and left ventricular ejection fraction and exercise response were not significantly different from those reported five years before. Individual changes in values were within the normal variation seen in serial studies. This long term longitudinal follow up of patients after the Mustard operation showed that although some patients still had right and left ventricular dysfunction, resting ventricular function and exercise response remained stable over a five year period. This preservation of cardiac function may contribute to the long term survival of patients after the Mustard procedure.

Adolescent↗
PubMed1986

Hepatobiliary scintigraphy. Increasing the accuracy of the preoperative diagnosis of acute cholecystitis.

The ability of hepatobiliary scintigraphy (HBS) to influence accurately the clinical diagnosis of acute cholecystitis was assessed prospectively in 70 consecutive patients with suspected acute cholecystitis. Before and after HBS, the referring surgeons completed a questionnaire on the probability of acute cholecystitis. Accuracy of diagnosis was assessed by clinical follow-up and chart review in all patients and by surgical and pathological evaluation in the 31 patients who underwent laparotomy. There were 27 patients with positive HBS results and 40 with negative HBS results; the results for three patients were indeterminate. None of the positive or negative HBS results were confirmed to be inaccurate. Negative results influenced diagnosis more often than did others. Results were negative in 13 patients whose assigned probability of acute cholecystitis was very high before HBS; in all 13 the assigned probability was very low after HBS, and in none of these patients was acute cholecystitis confirmed subsequently. These results support the use of hepatobiliary scintigraphy before proceeding to urgent cholecystectomy in patients with a clinical diagnosis of acute cholecystitis.

Acute Disease↗
PubMed1985

Radionuclide assessment of ventricular contraction at rest and during exercise following the Fontan procedure for either tricuspid atresia or single ventricle.

Ventricular contraction was evaluated in 18 patients studied at a mean of 2.6 years after Fontan repair. The diagnosis was tricuspid atresia in 9 patients and single ventricle in 9. Gated first-pass and gated equilibrium radionuclide ventriculography were performed at rest and during exercise. Abnormally low ventricular ejection fraction (EF) at rest was present in 8 of 18 patients by the gated equilibrium technique and 6 of 13 technically adequate gated first-pass studies. An abnormal response to exercise (failure of EF to increase less than or equal to 5% from rest to maximal exercise) was found in 10 of 16 patients by the gated equilibrium technique and in 8 of 12 by the gated first-pass technique. Only 2 patients by each radionuclide technique had both normal EF at rest and normal exercise response. Thus, this study confirms the frequent presence of abnormalities in ventricular contraction after the Fontan procedure at rest or during exercise or both despite absence of symptoms. Both EF response and the hemodynamic response during exercise were more abnormal in the presence of an atriopulmonary than an atrioventricular connection.

Adolescent↗
PubMed1985

Assessment of hemodynamic significance of isolated stenoses of the left anterior descending coronary artery using thallium-201 myocardial scintigraphy.

This study tests the hypothesis that the results of stress thallium-201 myocardial perfusion scans (TI-201) are related to the mean transstenotic pressure gradient of coronary stenoses independent of the percent luminal diameter narrowing seen at angiography. The 22 study patients (20 men, 2 women, mean age 47 years, range 30 to 62) had no previous myocardial infarction. Each underwent a symptom-limited, erect bicycle TI-201 test off antianginal therapy, shortly before percutaneous transluminal coronary angioplasty for isolated left anterior descending coronary artery stenosis. The percent narrowing, mean gradient at percutaneous transluminal coronary angioplasty and presence of a visually apparent TI-201 defect were independently evaluated and results compared. All 4 patients with 90% or greater diameter narrowing had positive TI-201 responses, and the mean gradient was 72 +/- 11 mm Hg. Among the 18 patients with less than 90% diameter narrowing, the mean gradient was higher (p less than 0.001) in the 11 with a positive TI-201 (63 +/- 15 mm Hg) than in the 7 with a negative TI-201 (33 +/- 20 mm Hg), but their percent narrowing did not differ significantly (72 +/- 14% vs 66 +/- 19%). Multiple regression analysis showed that the presence of a TI-201 defect was a strong (p = 0.003) and percent narrowing (p = 0.048) a weak independent predictor for gradient. When the mean gradient was normalized for the prestenotic pressure, both percent narrowing (p = 0.003) and TI-201 defects (p = 0.006) were significant independent predictors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Localization of exercise-induced myocardial ischemia with single view and biplanar radionuclide ventriculography: validation in single vessel coronary disease.

The ability of single view and biplanar radionuclide ventriculography (RVG) to determine the location of myocardial ischemia during maximal graded supine bicycle exercise was assessed in 50 patients with chest pain, no prior myocardial infarction, and a single coronary stenosis of greater than or equal to 50% luminal diameter narrowing at coronary angiography. A biplane collimator was used so that both right anterior oblique (RAO) gated first-pass and left anterior oblique (LAO) equilibrium RVG could be performed at rest and exercise. Results were compared with those obtained using 4-view 201Tl myocardial scintigraphy in the same patients. Regional wall motion abnormalities (WMA) and 201Tl perfusion defects were detected and assigned to individual coronary vessels by agreement between at least two of three independent observers, who read all studies blinded along with those from control subjects with chest pain but no angiographically significant coronary artery disease. When scintigraphic abnormalities were detected, both biplanar RVG (36/39 = 92%) and 201Tl (25/25 = 100%) were more frequently correct in predicting the stenosed vessel than single view LAO RVG (24/32 = 75%) (P less than 0.05). At RVG only inferior WMA, in the RAO view, predicted right coronary stenosis. Only posterolateral WMA, in the LAO view, predicted left circumflex stenosis. Thus biplanar, but not single view, LAO exercise RVG is a reasonable alternative to exercise 201Tl for localizing exercise-induced ischemic abnormalities to individual coronary stenoses.

Adult↗
PubMed1985

Value of combined assessment of global and segmental ventricular contraction with right anterior oblique ECG-gated first-pass and left anterior oblique equilibrium radionuclide ventriculography.

A semi-automated, variable-region-of-interest method of analysis was used to measure both global and segmental left ventricular (LV) and global right ventricular (RV) contraction with ECG-gated first-pass and equilibrium radionuclide ventriculography. Normal values were defined in 20 healthy volunteers, and in 24 symptomatic patients, the results were compared with right anterior oblique (RAO) contrast left ventriculography. The global LV ejection fraction (LVEF) obtained by equilibrium imaging in the left anterior oblique (LAO) projection correlated closely with the results obtained by the gated first-pass method in the RAO projection (r = 0.95) and those obtained with contrast left ventriculography (r = 0.94); furthermore, the interobserver variability was small (r = 0.985). The normal values for LVEF obtained using radionuclide techniques and contrast ventriculography did not differ, but with the equilibrium radionuclide method, the RV ejection fraction (RVEF) values were underestimated in comparison to those obtained by the RAO gated first-pass technique. In five patients with localised inferior segmental akinesis at contrast angiography, the RAO first-pass cine display demonstrated a corresponding wall-motion abnormality in all cases, but LAO equilibrium cine displays did so in only one out of five patients. For segmental quantitation of LV contraction, a computer programme defined the ventricular edge, divided the RAO LV images into five segments and determined both the segmental area contraction (SAC) and the counts-based segmental ejection fraction (SEF). Radionuclide SAC measurements correlated very strongly with SEF measurements (r = 0.94-0.99). Both radionuclide SAC and radionuclide SEF correlated well with contrast angiographic SAC, except in the inferobasal segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

omega-123I-hexadecanoic acid metabolic probe of cardiomyopathy.

The utility of omega-123I-hexadecanoic acid myocardial scintigraphy as a metabolic probe of cardiomyopathies was investigated. Sixteen patients with a variety of cardiomyopathies and myopathies that involve cardiac muscle and ten volunteers were imaged in the postabsorptive state in a 40 degrees LAO projection after a standard dose of omega-123I-hexadecanoic acid. An elimination T1/2 was calculated from the left ventricular myocardial time-activity curve. An uptake index, corrected for chest wall attenuation, was also computed in 7 of 10 volunteers and 8 of 16 patients. Of the 16 patients, only 2 had distinctly abnormal omega-123I-hexadecanoic acid myocardial tracer kinetics. The first patient had a metabolic disorder of which carnitine deficiency was one component. The second patient had endocardial fibroelastosis, a process which has been linked to disorders which deprive the myocardium of oxygen and energy. Therefore, the cardiomyopathy may have been caused by some abnormality of cardiac metabolism other than carnitine deficiency. Although of limited utility in the overall cardiomyopathic population, omega-123I-hexadecanoic acid myocardial scintigraphy should be further investigated as a screening test for carnitine deficiency and related metabolic abnormalities in patients at risk.

Adolescent↗
PubMed1985

Non-invasive assessment of pulmonary blood supply after staged repair of pulmonary atresia.

Radionuclide studies were performed to determine pulmonary blood flow in six children who had undergone surgery for pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary arteries with or without major aortopulmonary collateral arteries. Lung blood flow was assessed from both particle perfusion lung scans and the pulmonary and systemic phase of a radionuclide dynamic flow study. Five patients had perfusion defects identified on the particle perfusion lung scan. In three of these, abnormal areas were perfused only during the systemic phase of the flow study, a combination of findings that indicate the presence of perfusion by collateral arteries. In one patient no systemic perfusion was noted and in one an initial particle perfusion study indicated the presence of a lung segment perfused by a collateral artery. In this last patient the particle perfusion scan after total correction showed a reduction in the size of the lung perfusion defect and no evidence of lung perfusion during the systemic phase of the flow study. The particle perfusion lung scan in the sixth patient showed pronounced asymmetry in blood flow to the lungs with no segmental perfusion defect on the particle perfusion scan and no abnormalities on the systemic flow study. It is concluded that radionuclide lung perfusion and flow studies provide useful information on lung perfusion and merit further evaluation to define their role in the management of these patients.

Abnormalities, Multiple↗
PubMed1984

Enalapril for severe congestive heart failure. A double-blind study.

The effects of the new, orally administered converting-enzyme inhibitor, enalapril (MK-421), were studied in 12 ambulatory patients with severe cardiac failure who were also receiving digoxin and diuretic agents. The study was double-blind, parallel, placebo-controlled and randomized. The clinical characteristics and pretreatment exercise performance were similar in the two groups of patients. All vasodilator drugs had been withdrawn two weeks before the start of the trial. At 12 weeks, the patients receiving enalapril showed a significant improvement in the functional class of the disease, exercise time (P less than 0.01), and maximum workload achieved, and experienced relief of symptoms. Blood pressure fell in patients receiving active treatment suggesting a reduction of afterload. Left ventricular ejection fraction was unchanged in enalapril-treated patients, but fell in patients on placebo (P less than 0.001). Enalapril was well tolerated without apparent adverse effects. It was effective when used with digoxin and diuretic agents in the treatment of severe cardiac failure, and its efficacy was maintained throughout 12 weeks of therapy.

Administration, Oral↗
PubMed1984

Scintigraphic localization of a recurrent phaeochromocytoma by means of iodine-131 metaiodobenzylguanidine.

A new adrenomedullary scintigraphic imaging agent, iodine-131-labelled metaiodobenzylguanidine (MIBG), was used to localize a recurrent phaeochromocytoma in a 27-year-old man in whom the site of tumour could not be determined by any other means. MIBG scintigraphy is easy to perform and is highly specific for functioning aberrant adrenomedullary tissue. It complements other methods for localization of phaeochromocytoma and, under some circumstances, it may become the initial imaging procedure of choice in the screening of patients in whom the biochemical or clinical evidence suggests the presence of such tumours.

3-Iodobenzylguanidine↗
PubMed1984

Bilateral pheochromocytomas.

Bilateral pheochromocytomas most often occur as components of well-described syndromes: multiple endocrine neoplasia types 2a and 2b, von Hippel-Lindau disease and neurofibromatosis. We describe 4 patients with isolated bilateral pheochromocytomas; their tumors arose in the absence of stigmata and family history of the syndromes. The manifestations of these 4 individuals are compared with those of 14 other patients who developed pheochromocytomas in both adrenal glands as part of the syndromes. The 4 patients with the isolated pheochromocytomas manifest more rapidly progressing disease: they were 10-14 yrs of age, distinctly younger than those with the syndrome. Three of the 4 exhibited adrenal medullas that were composed entirely of tumor in contrast to the hyperplasia that usually accompanies other bilateral pheochromocytomas. However, malignant transformation of pheochromocytomas was seen both in a non-syndrome patient and in a patient with Lindau's disease.

Adolescent↗
PubMed1984

The effect of dobutamine on exercise performance in patients with symptomatic ischemic heart disease.

The effect of dobutamine on exercise performance was assessed in 20 patients with ischemic heart disease (CAD) and a positive stress test. These patients had a wide range of resting left ventricular ejection fraction (range 22% to 69%, mean 42%). Each patient entered a double-blind crossover study in which two identical exercise radionuclide ventriculograms were performed in patients on dobutamine, 5 micrograms/kg/min intravenously, or placebo. Dobutamine increased resting left ventricular ejection fraction. Although ejection fraction fell with dobutamine during submaximal exercise, it remained higher than with placebo. At peak exercise, ejection fraction fell to the same level on dobutamine as with placebo. Dobutamine diminished exercise time and time to ischemia while peak pressure-rate product was unchanged. Four of 20 patients developed complex ventricular premature beats, all while on dobutamine. Although useful when administered to resting patients with acute left ventricular failure, dobutamine's effects may be deleterious in exercising patients with chronic ischemic heart disease.

Adult↗
PubMed1984

Right and left ventricular function at rest and with exercise after the Mustard operation for transposition of the great arteries.

Right and left ventricular function was assessed in 25 children (mean age at study 12.2 years and at operation 2.6 years) after a Mustard repair for transposition of the great arteries. Gated first pass and gated equilibrium radionuclide ventriculography was performed on all patients at rest and during supine bicycle exercise. The mean right ventricular ejection fraction did not increase with exercise by either technique. Individual results for right ventricular ejection fraction showed that with the gated equilibrium technique 71% had an abnormal exercise response (normal response being an increase in ejection fraction greater than 5%) and with the gated first pass technique 61% had abnormal results. Although the mean left ventricular ejection fraction increased significantly with exercise, 35% of patients had an abnormal exercise response with the equilibrium technique and 41% with the first pass technique. There was no evidence of a predictive relation between ventricular function and any clinical or haemodynamic variable examined. Covert right and left ventricular dysfunction can frequently be detected by exercise radionuclide ventriculography in long term survivors of repair for transposition of the great arteries. The prognostic consequences of these findings are unclear at present.

Adolescent↗