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Biomedical subjects

A Movahed

Publications and source records attributed to A Movahed.

At least 37 records · Page 2Linked to original sources
PubMed1994

Successful treatment of myocardial sarcoidosis with steroids.

Myocardial involvement in sarcoidosis occurs in approximately twenty-seven percent of patients and may result in a grim prognosis. The diagnosis is mainly clinical and may be supplemented by echocardiography, thallium imaging, Gallium-67 scanning, and myocardial biopsy. The value of corticosteroid treatment is still not well-established and few patients have benefitted from cardiac transplantation. We present a case with suspected myocardial sarcoidosis and congestive heart failure who had dramatic response to steroid therapy on five weeks' followup.

Adult↗
PubMed1994

Alteration of coronary perfusion reserve in hypertensive patients with diabetes.

This investigation was performed to determine whether diabetes mellitus has an additive effect on diminishing coronary perfusion reserve index in hypertensive patients. Coronary perfusion reserve index, thallium lung uptake, the electrocardiogram and haemodynamic parameters were evaluated by exercise thallium myocardial perfusion scintigraphy. In 18% of hypertensive and 13% of diabetic-hypertensive patients there was evidence of left ventricular hypertrophy on electrocardiogram. The maximum heart rate achieved in hypertensive, diabetic and diabetic-hypertensive patients was significantly lower (P < 0.05) than in control patients. The maximum SBP achieved in hypertensive (210 +/- 40 mmHg) and diabetic-hypertensive patients (216 +/- 36 mmHg) was higher (P < 0.05) than in control patients (186 +/- 32 mmHg). A significantly higher number of diabetic patients (53%) did not achieve the exercise rate pressure product of > 26,000 when compared with control (27%), hypertensive (24%) and diabetic-hypertensive (30%) patients. Coronary perfusion reserve index in hypertensive patients decreased significantly (P < 0.05) when compared with control (no hypertension, no diabetes) patients (1.67 +/- .14 vs. 1.79 +/- .17). Coronary vasodilatory reserve index was also reduced significantly (P < 0.05) in diabetic patients in comparison with controls (1.66 +/- .17 vs. 1.79 +/- .17), and was further reduced in diabetic-hypertensive patients when compared with control patients (1.63 +/- .13 vs. 1.79 +/- .17). Thallium uptake in the lung quantified as thallium lung to heart ratio were comparable in all four groups. The results suggest that diabetes mellitus diminishes the coronary perfusion reserve index in patients with hypertension and therefore many account for the increased cardiovascular morbidity in these patients.

Adult↗
PubMed1993

Sarcoidosis of the heart.

Myocardial involvement in sarcoidosis occurs in about 27% of patients. Clinical manifestations include ventricular arrhythmias, conduction abnormalities, and sudden death. Diagnosis requires clinical suspicion and may be supported by electrocardiography, echocardiography, thallium imaging, gallium-67 scanning, and myocardial biopsy. Steroids seem to be beneficial in the treatment of myocardial sarcoidosis. Those who do not respond to medical treatment may benefit from cardiac transplantation.

Biopsy↗
PubMed1993

Effect of hyperkalemia on myocardial depression by verapamil in isolated hearts.

Verapamil can produce depression of left ventricular function, delayed atrioventricular conduction, and hypotension, which can be potentiated by hyperkalemia. We sought to investigate a direct cardiac interaction between verapamil and hyperkalemia. Studies utilized isolated guinea pig hearts (Langendorff) paced at 250 beats/min. Hearts were randomly assigned to perfusion (Krebs-Henseleit buffer) with potassium concentrations ([K]+) of 1.5, 3, 6 and 9 mmol/l. Infusion of verapamil at rates of 0.2 to 60 micrograms/min (approximately 3 x 10(-8) to 10(-5) mol/l) produced concentration-dependent reduction of isovolumic left ventricular developed pressure. As [K]+ increased, concentration response curves showed parallel shifts to the left. The ED50 for reduction of left ventricular developed pressure significantly decreased: 8.2 +/- 3.7, 2.9 +/- 1.4, 1.2 +/- 0.7, 0.6 +/- 0.2 micrograms/min (mean +/- SD), respectively. Nifedipine and diltiazem were also studied in hearts perfused with 3 and 9 nmol/l [K]+. Infusion of nifedipine 0.003-1 microgram/min (approximately 10(-9) to 3 x 10(-7) mol/l) produced concentration-dependent reduction of left ventricular developed pressure but the ED50 was not affected by [K]+: 0.06 +/- 0.03 and 0.05 +/- 0.04 microgram/min, respectively. Nifedipine vehicle was without effect at the infusion rates tested. Infusion of diltiazem 2-200 micrograms/min (approximately 3 x 10(-7) to 3 x 10(-5) mol/l) also produced concentration-dependent reduction of left ventricular developed pressure. The ED50 for diltiazem-induced reduction of left ventricular developed pressure was significantly reduced by elevated [K]+: 20.1 +/- 6.7 and 3.5 +/- 0.9 micrograms/min with 3 and 9 mmol/l [K]+, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Cardiac complications of intensive dose mitoxantrone and cyclophosphamide with autologous bone marrow transplantation in metastatic breast cancer.

Fifteen women with metastatic breast cancer undergoing autologous bone marrow transplantation were treated with an intensive induction regimen including cyclophosphamide and mitoxantrone in a phase I-II study. The cardiotoxicity of these two drugs in combination have not been previously reported. Three patients developed deeply inverted T-waves during or shortly following conclusion of high-dose chemotherapy with associated declines in ejection fraction of 0.04, 0.19 and 0.27. One patient developed a brief episode of congestive heart failure which resolved with supportive care. These three patients were the only ones to have received previous left chest wall radiotherapy during the course of their disease, prior to treatment with autologous bone marrow rescue. No patient developed dysrhythmia or QRS changes during a mean hospital stay of 33.7 days (range 27-40 days).

Adult↗
PubMed1992

Effect of diltiazem on norepinephrine-induced acute left ventricular dysfunction.

The present study has examined the role of diltiazem as a protective agent in a canine model of norepinephrine cardiotoxicity. Effects of diltiazem, 20 micrograms/kg/min x 5 min pretreatment followed by 10 micrograms/kg/min x 90 min, or saline infusion were examined at baseline and 1 h after infusion of norepinephrine, 4 micrograms/kg/min for 90 min, in closed-chest anesthetized dogs. Left ventricular function was assessed by equilibrium radionuclide angiogram and two-dimensional echocardiogram. In 7 saline experiments, hypotension and increased heart rate were observed at 1 h post infusion. In the diltiazem-treated group (n = 7), mean arterial pressure and heart rate were unchanged. In the saline group, left ventricular ejection fraction fell from 0.50 +/- 0.04 to 0.28 +/- 0.04. Left ventricular ejection fraction was unchanged in the diltiazem-treated group: 0.52 +/- 0.03 to 0.55 +/- 0.07. Left ventricular end-diastolic volume was increased at 1 h post infusion in saline controls but not in the diltiazem-treated group. Measurement of fractional shortening from two-dimensional echocardiograms also indicated left ventricular dysfunction in the saline but not diltiazem-treated groups. Left ventricular end-systolic wall stress following norepinephrine infusion was significantly increased in the saline but not diltiazem-treated groups: 122.7 +/- 18.7 vs 67.6 +/- 19.7 g/cm2, respectively. In dogs receiving saline without norepinephrine infusion, no significant changes occurred over the course of the experiment. Histologic examination showed mild contraction band necrosis in saline controls but not in sham saline dogs. Diltiazem showed intermediate histologic evidence of injury, which was not further quantified. This study suggests that effects of norepinephrine on left ventricular function in the canine model of norepinephrine cardiotoxicity may be largely due to increased wall stress following a prolonged increase in afterload. Diltiazem pretreatment afforded significant protection of left ventricular function.

Animals↗
PubMed1992

Significance of increased Tl-201 uptake by the lungs in patients undergoing oral dipyridamole-thallium myocardial imaging.

The purpose of this study was to evaluate the significance of increased Tl-201 uptake by the lungs after oral dipyridamole testing. In conjunction with myocardial perfusion scintigraphy, intravenous dipyridamole has been recently approved as an alternative to exercise for the evaluation of coronary artery disease in patients who cannot adequately exercise, and it will largely replace oral dipyridamole testing. This study contributes to the understanding of the significance of increased lung thallium uptake during pharmacologic stress testing. Oral dipyridamole, 400 mg, was administered to 192 patients undergoing Tl-201 imaging for clinical indications. Mild adverse effects occurred in 31% of patients (chest pain, nausea, headache, or flushing). Dipyridamole had minimal hemodynamic effects. The lung/heart thallium activity ratio was determined in 152 patients. These were subdivided into four groups according to the presence or absence of ischemia, transient myocardial perfusion defect, or scar as indicated by a fixed myocardial perfusion defect. In 61 patients without transient myocardial perfusion defect or fixed myocardial perfusion defect (group 1), the lung/heart thallium activity ratio was 0.39 +/- 0.01 (mean +/- SEM). In 31 patients without transient myocardial perfusion defect but with fixed myocardial perfusion defect (group 2), the lung/heart thallium activity ratio was higher, 0.44 +/- 0.02 (P less than 0.05). In 27 patients with transient myocardial perfusion defect but no fixed myocardial perfusion defect (group 3) and in 33 patients with both transient myocardial perfusion defect and fixed myocardial perfusion defect (group 4), the lung/heart thallium activity ratio was 0.51 +/- 0.03 and 0.52 +/- 0.03, respectively, both significantly higher than either group 1 or group 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Atrial fibrillation: current therapeutic approaches.

Atrial fibrillation is associated with potentially life-threatening strokes. Anticoagulation with warfarin or aspirin reduces the risk of embolic events in patients with chronic atrial fibrillation and mitral valve stenosis or other underlying heart disease. In patients with acute onset of atrial fibrillation, anticoagulation is not necessary before cardioversion. However, in patients with chronic atrial fibrillation, anticoagulation should be started three weeks before cardioversion and continued for four weeks after the return of normal sinus rhythm. Quinidine remains the agent most commonly used for medical cardioversion in patients who are hemodynamically stable. If a patient is hemodynamically unstable or the atrial fibrillation is not corrected with drug therapy, direct-current electrical cardioversion has a high success rate. Antiarrhythmic (quinidine) therapy is often continued indefinitely to help maintain sinus rhythm.

Adrenergic beta-Antagonists↗
PubMed1992

Thrombolytic therapy in acute myocardial infarction.

Multiple clinical trials have demonstrated that thrombolytic treatment early in the course of acute myocardial infarction significantly reduces mortality. Patients under 75 years of age who have had chest pain for no longer than six hours and who demonstrate ST-segment elevation on electrocardiogram are the best candidates for this therapy. Recent studies suggest that there is little difference in effectiveness among streptokinase, alteplase and anistreplase. However, streptokinase is 10 times less expensive than the other agents and causes fewer intracranial bleeds, the major serious adverse effect of thrombolytic therapy. An advantage of anistreplase is that it can be given in a five-minute bolus injection, compared with a one-hour infusion for streptokinase and a three-hour infusion for alteplase. Thrombolytic therapy is contraindicated in patients with known pregnancy, active internal bleeding, uncontrolled hypertension, aortic dissection, intracranial neoplasm or a history of hemorrhagic stroke. Heparin should be administered with both alteplase and streptokinase. Aspirin, beta blockers, nitrates and lidocaine are useful adjunctive therapies in the setting of an acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1991

Effect of hyperkalemia on experimental myocardial depression by verapamil.

Three patients with systemic hypotension and sinus bradycardia that were initially refractory to conventional therapy responded well to intravenous calcium administration. Two-dimensional echocardiography revealed immediate reversal of severe left ventricular dysfunction after intravenous administration of calcium in two instances. Common factors were hyperkalemia and verapamil therapy. This interaction was examined further by evaluation of contractility, heart rate, and arterial blood pressure in anesthetized dogs. Controls (n = 9) received saline infusion, and a second group (n = 10) received saturated potassium chloride (approximately 0.2 ml/min intravenously). In control dogs, administration of verapamil (1195 +/- 181 micrograms/kg intravenously) reduced systemic arterial pressure from 113 +/- 7 mm Hg to 74 +/- 5 mm Hg, and heart rate from 147 +/- 9 beats/min to 86 +/- 11 beats/min. Potassium chloride infusion alone increased blood [K+] from 3.4 +/- 0.1 to 6.2 +/- 0.2 mEq/L, but was without hemodynamic effects. In hyperkalemic dogs, a significantly lower dose of verapamil (428 +/- 42 micrograms/kg intravenously) reduced systemic arterial pressure from 102 +/- 8 mm Hg to 36 +/- 4 mm Hg, and heart rate from 150 +/- 5 beats/min to 104 +/- 15 beats/min. Myocardial contractile function was examined with right ventricular isometric contractile force and left ventricular segment length changes. In normokalemic and hyperkalemic groups, contractility was decreased by verapamil. Effects of verapamil on arterial pressure and contractility could be reversed significantly by administration of calcium, 0.4 mEq/kg intravenously. The present results support the theory that the negative hemodynamic effects of verapamil may be exaggerated to a harmful degree by concomitant hyperkalemia. These adverse events may be reversed by calcium administration.

Acute Disease↗
PubMed1991

Myocardial imaging artifacts caused by mitral valve annulus calcification.

Knowledge of imaging artifact of myocardial perfusion studies with thallium-201 is critical for improving the diagnostic accuracy of coronary artery disease. Three patients are described who underwent exercise or pharmacologic stress thallium-201 imaging studies and had a moderate, fixed myocardial perfusion defect (scar) involving the posterolateral and inferoposterior walls of the left ventricle. This was an imaging artifact caused by a heavily calcified mitral valve annulus.

Aged↗
PubMed1991

Effect of neuropeptide Y on isolated rat hearts.

Neuropeptide Y (NPY) induces coronary vasoconstriction and an associated negative inotropic effect in the isolated rat heart, but it is unclear whether NPY produces these effects directly or through the mediation of other vasoactive substances. This question has been examined in Langendorff-perfused, paced hearts using constant pressure. In 22 dose-response experiments examining single injections of NPY, 0.05-5 nmol, into the coronary perfusate, dose-dependent reduction of flow and developed pressure was observed. NPY, 0.5 nmol or approximately 5 x 10(-8) M, was chosen for further studies. This dose produced close to maximal effects on coronary flow, -22 +/- 5%, and developed pressure, -14 +/- 5% (mean +/- SD). NPY was examined during infusion of the cyclooxygenase inhibitor indomethacin (n = 6) and the 5-lipoxygenase inhibitor RG 6866 (N-methyl-4-benzyloxyphenyl acetohydroxamic acid, n = 6), using a test dose for both agents of 20 micrograms/min (approximately 3 microM) or vehicle (ethanol, 0.01 ml/min, n = 9). NPY reduced coronary flow in all three groups: vehicle 6.2 +/- 1.1 to 4.6 +/- 1.1 ml/min, indomethacin 7.0 +/- 1.1 to 5.7 +/- 1.0, and RG 6866 7.0 +/- 1.6 to 6.1 +/- 1.6; reductions of 25 +/- 7, 19 +/- 5 and 13 +/- 9%, respectively. The flow reduction was attenuated by RG 6866. Developed pressure was significantly reduced by NPY in vehicle 71 +/- 10 to 62 +/- 11 mm Hg, and indomethacin 70 +/- 10 to 64 +/- 11 but not RG 6866 74 +/- 15 to 71 +/- 15 groups, reductions of 13 +/- 3, 9 +/- 9 and 4 +/- 5%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Radionuclide myocardial perfusion imaging.

Objective assessment of myocardial perfusion is important in the diagnosis, management and long-term follow-up of patients with coronary artery disease. Thallium-201 perfusion imaging provides valuable information about myocardial viability, regional myocardial blood flow and physiologically important coronary artery disease at rest, during exercise and during pharmacologically induced coronary vasodilation. Dipyridamole "stress" myocardial imaging is indicated in the evaluation of patients who are unable to exercise or who cannot achieve 85 percent of the maximum predicted heart rate. It also may be useful in the preoperative assessment of patients undergoing elective vascular surgery.

Coronary Vessels↗