PubMed Health⌕ Search

Biomedical subjects

N W Shammas

Publications and source records attributed to N W Shammas.

At least 19 recordsLinked to original sources
PubMed2001

Digoxin withdrawal in patients with dilated cardiomyopathy following normalization of ejection fraction with beta blockers.

BACKGROUND: The effect of withdrawal of digoxin on left ventricular function in patients with a history of idiopathic dilated cardiomyopathy (IDCM) following normalization of left ventricular ejection fraction (LVEF) with beta blockers remains unknown. HYPOTHESIS: This study was undertaken to determine the effect of digoxin withdrawal on left ventricular function in patients with IDCM. METHODS: In 8 consecutive patients with IDCM (5 men, 3 women) who had normalization of LVEF following beta-blocker treatment, digoxin was withdrawn as part of an office protocol. and LVEF was followed. Baseline EF prior to beta blocker initiation (carvedilol = 6, atenolol = 1, metoprolol 1) was measured with isotope ventriculography (IVG), echocardiography, or left ventriculography. Post beta blocker ejection fraction (post BB EF) was measured in all patients with IVG at a mean of 17.25 +/- 5.38 months. Follow-up EF was measured using IVG after digoxin withdrawal at a mean of 6.99 +/- 4.34 months. RESULTS: An experienced blinded reader interpreted the IVG scans. Baseline EF was 28.5 +/- 8.26; post BB EF and follow-up EF were 56.1 +/- 4.65 and 51.0 +/- 7.35, respectively (p = 0.05). CONCLUSION: These data provide potential evidence that digoxin withdrawal can result in a small but significant reduction in LVEF in patients with IDCM who had normalization of LVEF after treatment with beta blockers. Mean LVEF, however, remained within normal (> 50%) on beta-blocker therapy and without digitalis. Large, randomized controlled trials are needed to confirm these findings.

Adrenergic beta-Antagonists↗
PubMed2001

Aminophylline does not protect against radiocontrast nephropathy in patients undergoing percutaneous angiographic procedures.

BACKGROUND: Radiocontrast nephropathy (RCN) is one of the leading causes of hospital-acquired acute renal insufficiency. Adenosine, a renal vasoconstrictor, is thought to play a role in RCN. In this study, aminophylline, a non-selective adenosine-competitive inhibitor, was evaluated as a potential agent to protect against RCN. METHODS: Twenty-six patients treated with 200 mg intravenous aminophylline immediately prior to percutaneous coronary and peripheral procedures were individually matched to 26 controls for baseline creatinine (Cr), diabetes mellitus and amount of contrast used. The aminophylline-treated group was also similar to control with respect to baseline ejection fraction, amount of post-procedure hydration, age, blood pressure and the use of nephrotic drugs. RESULTS: There was no significant difference between the change from baseline Cr to peak measured Cr in either cases or controls. Also, when a change in Cr > or =25% from baseline was considered significant, Fisher's exact test did not show a difference between the 2 groups. CONCLUSION: Aminophylline does not appear to add a protective role in preventing against RCN in patients undergoing percutaneous angiographic procedures.

Aged↗
PubMed2000

Pulmonary embolus after coronary artery bypass surgery: a review of the literature.

Pulmonary embolus (PE) after cardiac bypass surgery is an uncommon complication but carries with it high morbidity and mortality. The incidence of deep vein thrombosis (DVT) and PE after cardiac bypass varies depending on postoperative thromboprophylaxis, the presence of indwelling central venous catheters in the lower extremities, and early ambulation. The clinical diagnosis of DVT remains difficult and challenging. Pulmonary embolus is often the first occurring clinical event. The safety and effectiveness of preventative pharmacologic agents, such as subcutaneous unfractionated or fractionated heparin or oral coumadin, remain largely unknown. Heparin-induced thrombocytopenia, generally associated with a high incidence of DVT and PE, occurs in approximately 3.8% of patients who have undergone cardiac surgery and are placed postoperatively on high-dose intravenous unfractionated heparin. Sequential compression devices (SCD) have not been effective in reducing the incidence of DVT in an ambulating cardiac bypass patient when added to routine elastic graded compression stockings (GCS). Very large clinical trials are necessary to prove the effectiveness of pharmacologic or mechanical preventative measures in reducing the incidence of PE after cardiac surgery above the commonly used GCS, early ambulation, and aspirin. In a nonambulating, higher-risk cardiac bypass patient with slow recovery, a more aggressive prophylaxis regimen might be necessary for optimal prevention, although further data are needed to support this hypothesis.

Anticoagulants↗
PubMed1996

Evaluation of diabetic patients for renal and pancreas transplantation: noninvasive screening for coronary artery disease using radionuclide methods.

Pharmacologic stress thallium scintigraphy is commonly performed in the risk assessment of diabetic patients with nephropathy before kidney and/or pancreas transplantation; however, controversy exists regarding the test's accuracy in detecting coronary artery disease. Our purpose was to compare pharmacologic stress thallium scintigraphy and also exercise radionuclide ventriculography with coronary angiography in diabetic patients undergoing evaluation for transplantation. In addition, we also determined the association of the test results with outcome after transplantation. The medical records of 47 patients (mean age, 37+/-9 years) without clinical evidence of coronary artery disease were reviewed. Forty-one patients had pharmacologic stress thallium scintigraphy performed during their evaluation. Sensitivity was 62% and specificity was 76% for detecting > or = 75% coronary artery stenosis (sensitivity was 53% and specificity was 73% for > or = 50% stenosis). Thirty-five patients had exercise radionuclide ventriculography performed. Sensitivity was 50% and specificity was 67% for detecting > or = 75% coronary artery stenosis (sensitivity was 44% and specificity was 63% for > or = 50% stenosis). Thirty patients had both pharmacologic stress thallium scintigraphy and exercise radionuclide ventriculography performed; when either test was abnormal, sensitivity in the detection of > or = 50% or > or = 75% stenosis tended to increase compared with pharmacologic stress thallium scintigraphy alone (0.05<P<0.10), whereas specificity decreased (P<0.01). The incidence of adverse cardiac outcomes was identical for patients with abnormal thallium scintigrams and undergoing transplantation (2/11) compared with patients with normal scintigrams and undergoing transplantation (4/22). We conclude that: (1) pharmacologic stress thallium scintigraphy and exercise radionuclide ventriculography are suboptimal screening tests for coronary artery disease in diabetic patients awaiting kidney and/or pancreas transplantation; (2) using the two radionuclide tests in combination results in a decrease in specificity; and (3) patients with abnormal thallium scintigrams can receive transplants with outcomes similar to those for patients with normal thallium scintigrams.

Adult↗
PubMed1996

Perforation of saphenous vein graft during coronary stenting: a case report.

We report on a case of coronary perforation during stenting of a saphenous vein graft with a biliary stent. Sealing of the perforation was achieved with another biliary stent deployed within the first stent at the site of the perforation, and with prolonged balloon inflation. This case illustrates that vein graft perforation can occur with coronary stenting, and could potentially be treated with prolonged balloon inflation and/or stenting at the site of the first stent.

Coronary Angiography↗
PubMed1996

Giant right coronary artery aneurysm with fistulous connection to the coronary sinus: diagnosis and management.

This report describes the case of a giant aneurysmal right coronary artery connecting to the coronary sinus near its opening into the right atrium in a 70-year-old woman who presented with a recent onset of congestive heart failure. By coincidence, a secundum atrial septal defect was also present. The diagnosis and surgical management of this uncommon pathology are described.

Aged↗
PubMed1994

Complete heart block complicating retrograde left ventricular catheterization: case report and review.

Complete heart block (CHB) following retrograde left ventricular catheterization is uncommon. We report a case of transient CHB in a patient with severe aortic stenosis and bifascicular block on the baseline surface electrocardiogram during retrograde left ventricular catheterization. The block resolved spontaneously without sequelae. A review of the literature using MedLine was performed and recommendations for temporary and permanent pacing are outlined.

Aged↗
PubMed1994

Markers of hemostatic activation in affected coronary arteries during angioplasty.

To characterize the extent of early activation of the hemostatic system following angioplasty, we obtained blood samples from the involved coronary artery of 11 stable angina patients during the procedure and measured sensitive markers of thrombin formation (fibrinopeptide A, prothrombin fragment 1.2, and soluble fibrin) and of platelet activation (beta-thromboglobulin). Levels of hemostatic markers in venous blood obtained from 14 young individuals with low pretest probability for coronary artery disease were not significantly different from levels in venous blood or intracoronary samples obtained prior to angioplasty. Also, there was no translesional (proximal and distal to the lesion) gradient in any of the hemostatic markers before or after angioplasty in samples obtained between 18 and 21 min from the onset of the first balloon inflation. Furthermore, no significant difference was noted between angioplasty and postangioplasty intracoronary concentrations. We conclude that intracoronary hemostatic activation does not occur in the majority of patients during and immediately following coronary angioplasty when high doses of heparin and aspirin are administered.

Adult↗
PubMed1993

Infective endocarditis due to Fusobacterium nucleatum: case report and review of the literature.

Endocarditis caused by Fusobacterium nucleatum is exceedingly rare. We report a case of F. nucleatum right-sided endocarditis in a patient with no known intravenous drug abuse. A detailed computer and manual search of the literature using Med-Line and Index Medicus, respectively, revealed a total of five cases of endocarditis due to this species. The clinical characteristics and the patient's hospital course are summarized and reviewed.

Dental Caries↗
PubMed1993

Intravenous thrombolytic therapy in myocardial infarction: an analytical review.

The properties and physiological effects of three currently FDA-approved thrombolytic agents, streptokinase (SK), tissue plasminogen activator (tPA), and anisoylated plasminogen activator complex (APSAC) are reviewed. All thrombolytic agents have been shown to reduce mortality postmyocardial infarction (MI). Comparative trials have failed to demonstrate a difference between the effects of tPA, SK, and APSAC on mortality. In addition, no consistent difference between the three agents on ejection fraction (EF) has been found despite a superior reperfusion rate with tPA at 90 min. Furthermore, reinfarction and interventional procedure rates were significantly higher after thrombolytic treatment, and the incidence of total strokes was higher with tPA than SK in some comparative studies. Based on analysis of the published megatrials, SK is a more cost-effective thrombolytic agent for patients with acute MI than tPA or APSAC.

Anistreplase↗
PubMed1993

Acquired coronary angiogenesis after myocardial infarction.

Acquired coronary artery microvascular fistulas have been reported in only a few patients after myocardial infarction. We describe 1 patient in whom serial coronary angiography demonstrated the development of coronary angiogenesis at the site of an old myocardial infarction. The area of neovascularity was associated with a large apical left ventricular thrombus. This finding suggests that growth-promoting mitogens are present in myocardium and thrombus and that angiogenesis occurs in some patients following myocardial infarction.

Coronary Angiography↗
PubMed1993

Septo-optic dysplasia associated with polyendocrine dysfunction.

Septo-optic dysplasia (SOD) is a rare congenital disease that has been described in association with hypothalamic dysfunction. A case of polyendocrine dysfunction is described in a 22 year-old white female with septo-optic dysplasia. Findings included atrophic optic nerves, a cavum septum pellucidum and a small pituitary gland detected by magnetic resonance imaging. The patient had central diabetes insipidus, Hashimoto's thyroiditis, and gestational diabetes mellitus. A review of the literature is presented. A careful and detailed endocrine evaluation is needed in patients with SOD.

Adult↗
PubMed1988

Prostacyclin-inhibition of lysine accumulation by the rat left ventricle.

1. Left ventricular slices of male Sprague-Dawley rats were incubated with a fixed concentration of 0.5 microCi/ml 3H-lysine and several concentrations of unlabelled lysine ranging from 0.2 to 5.0 mM in control and prostacyclin-treated experiments. The time of incubation ranged from 0.5 to 90 min. 2. Left ventricular slices were cut to have an optimal thickness of 0.47 +/- 0.09 mm. 3. Lysine was taken up against a concentration gradient. Saturation was reached at 0.5 mM and steady state accumulation of lysine was attained within 60 min. 4. Prostacyclin in concentrations ranging from 1.2 x 10(-8) to 4.8 x 10(-8) M inhibited lysine transport in left ventricular slices significantly (P less than 0.01).

Animals↗
PubMed1988

Dopaminergic and adrenergic binding affinities in rabbit retinal synaptosomes.

1. Dopamine binding to amacrine membrane vesicles isolated as synaptosomal fractions P1 and P2 from rabbit retinas showed saturation within less than a minute. 2. Dopamine binding to retinal synaptosomal membranes (RSM) in P1 and P2 is a two-component system: the first saturated at 1.00 microM 14C-dopamine in P1 and 1.25 microM in P2, and the second saturated at 2.00 microM in both pellets. 3. The affinity of RSM receptors to dopamine in P1 was equal to that in P2 (Km = 2.00 microM), whereas the calculated Vmax of dopamine binding was increased in P2 (1.25 pmol/micrograms protein) as compared to P1 (0.625 pmol/micrograms protein). 4. Dopamine binding to the beta-adrenergic sites showed a lower affinity (Km = 10 microM) in P2 relative to P1 (Km = 4.0 microM), whereas Vmax in P2 (5.0 pmol/micrograms protein) was 4-fold higher than P1 (1.25 pmol/micrograms protein). 5. The P1 and P2 fractions of rabbit RSM contain dopaminergic and beta-adrenergic binding sites with higher concentration of dopaminergic receptors and lower concentration of beta-adrenergic receptors in P2 relative to P1.

Animals↗
PubMed1988

Prostacyclin-enhanced calcium sequestration by microsomes isolated from rat left ventricle.

The objective of these experiments was to investigate the direct effect of prostacyclin on calcium binding and uptake by microsomal vesicles isolated from rat left ventricle. The protein content of the preparation was found to be 2.73 +/- 0.18 mg microsomal protein/g of left ventricular wet weight. Steady-state calcium binding and uptake by microsomal vesicles was reached at 6 minutes in control animals and 20 sec in prostacyclin-treated experiments. Prostacyclin increased steady-state calcium binding and uptake from a control of 52.48 +/- 4.16 up to 109.31 +/- 3.06 nmol/mg protein (p less than 0.05) and from 238.07 +/- 12.37 up to 314.85 +/- 1.23 nmol/mg protein (p less than 0.05) respectively. Doubling the concentration of prostacyclin from initial dose of 1.2 x 10(-8) M did not alter calcium binding and uptake further.

Animals↗