Search PubMed⌕ Search

Biomedical subjects

B Pitt

Publications and source records attributed to B Pitt.

At least 253 records · Page 14Linked to original sources
PubMed1981

Stress thallium-201 myocardial scintigraphy for the detection of individual coronary arterial lesions in patients with and without previous myocardial infarction.

The value of stress thallium-201 scintigraphy for detecting individual coronary arterial stenoses was analyzed in 141 patients with angiographically proved coronary artery disease, 101 with and 40 without a previous myocardial infarction. In patients without infarction, the sensitivity for detecting greater than 50 percent narrowing in the left anterior descending, the right and the left circumflex coronary artery was 66, 53 and 24 percent, respectively. In those with a previous infarction, the sensitivity for demonstrating disease in the artery corresponding to the site of infarction was 100 percent for the left anterior descending, 79 percent for the right and 63 percent for the left circumflex coronary artery. In patients with a prior anterior infarction, concomitant right or left circumflex coronary arterial lesions were detected in only 1 of 12 cases, whereas in those with previous inferior or inferolateral infarction, the sensitivity for left anterior descending coronary artery disease was 69 percent. Because of the reasonably high sensitivity for detecting left anterior descending arterial disease, irrespective of the presence and location of previous infarction, myocardial scintigraphy was useful in identifying multivessel disease in patients with a previous inferior infarction. However, because of its relative insensitivity for right or left circumflex coronary artery disease, scintigraphy proved to be a poor predictor of multivessel disease in patients with a prior anterior infarction and in patients without previous myocardial infarction.

Adult↗
PubMed1981

Exercise thallium-201 myocardial imaging in left main coronary artery disease: sensitive but not specific.

To determine the usefulness of thallium-201 scintigraphy for identifying left main coronary artery disease, the results of scintigraphy at rest and during exercise were compared in 24 patients with 50 percent or greater narrowing of the left main coronary artery and 80 patients with 50 percent or greater narrowing of one or more of the major coronary arteries but without left main coronary involvement. By segmental analysis of the scintigrams, perfusion defects were assigned to the left anterior descending, left circumflex or right coronary artery, singly or in combination, and the pattern of simultaneous left anterior descending and circumflex arterial defects was used to identify left main coronary artery disease. Of the 24 patients with left main coronary artery disease, 22 (92 percent) had abnormal exercise scintigrams. Despite this high sensitivity, the pattern of perfusion defects was not specific; the "left main pattern" was found in 3 patients (13 percent) with left main coronary artery disease but also in 3 (33 percent) of 9 patients with combined left anterior descending and left circumflex arterial disease, 4 (19 percent) of 21 patients with three vessel disease and 3 (6 percent) of 50 patients with one or two vessel disease but excluding the group with left anterior descending plus left circumflex arterial disease. The pattern of perfusion defects in the patients with left main coronary artery disease was determined by the location and severity of narrowings in the coronary arteries downstream from the left main arterial lesion. Concomitant lesions in other arteries were found in all patients with left main coronary disease (one vessel in 1 patient, two vessels in 7 patients and three vessels in 16). For this reason, it is unlikely that even with improvements in radiopharmaceutical agents and imaging techniques, myocardial perfusion scintigraphy will be sufficiently specific for definitive identification of left main coronary artery disease.

Coronary Circulation↗
PubMed1981

Radionuclide angiography in evaluation of left ventricular function following aortic valve replacement.

Congestive heart failure in patients surviving aortic valve replacement has been associated with a high late mortality. To determine whether myocardial dysfunction in these patients occurred preoperatively, perioperatively, or during the early postoperative period, 19 consecutive patients undergoing aortic valve replacement using cardioplegia and hypothermia were studied by multiple-gated cardiac blood pool imaging. The resting ejection fractions for 8 patients with aortic stenosis did not show significant changes following operation. The 11 patients with aortic insufficiency has resting preoperative values of 58 +/- 15%, which fell to 38 +/- 18% immediately postoperatively (p less than 0.01), with the late values being 51 +/- 16%. Eight of 18 patients (44%) showed deterioration of regional wall motion immediately after operation, which persisted in 3 during the late evaluation. The occurrence of new perioperative regional wall motion abnormalities and persistent perioperative depression in left ventricular function in some patients suggest the need for further improvement in myocardial protection during cardiopulmonary bypass for aortic valve replacement.

Adult↗
PubMed1981

Combined administration of nitroglycerin and propranolol to patients with acute myocardial infarction.

Hemodynamic effects of combined nitroglycerin and propranolol administration were investigated in patients with acute myocardial infarction. After nitroglycerin infusion decreased the mean arterial pressure by 20 mm Hg for one hour, nitroglycerin was continued, and patients were given 0.033 mg/kg of propranolol every five minutes for a total dose of 0.1 mg/kg, or until there was a decrease in heart rate to less than 60 beats/min, an increase in left ventricular filling pressure (LVFP) to greater than 15 mm Hg, or a decrease in systolic arterial pressure to less than 85 mm Hg. Seven of eight patients with initial LVFP less than or equal to 15 mm Hg and three of seven with initial LVFP greater than 15 mm Hg received 0.1 mg/kg of propranolol. Propranolol significantly decreased heart rate. Although pressure time/minute decreased significantly, the magnitude of its decrease was small, suggesting only a minimal effect on myocardial oxygen demands. The LVFP increased after giving propranolol but remained less than the control value. Simultaneous administration of nitroglycerin likely prevented further increases, since LVFP increased after cessation of nitroglycerin infusion, and three patients subsequently had pulmonary edema. Propranolol administration resulted in a significant increase in peripheral vascular resistance and a decrease in cardiac output.

Blood Pressure↗
PubMed1981

Insulin.

Explore the source record for details and available documents.

Canada↗
PubMed1981

Thallium-201 myocardial scintigraphy: a critical comparison of seven-pinhole tomography and conventional planar imaging.

Seven-pinhole tomographic and planar thallium-201 imaging was performed on 63 consecutive patients to assess the clinical value of these techniques. Significant coronary artery disease (stenosis greater than or equal to 70%) was present in 52 patients. Comparing the seven-pinhole results with those of the planar, the findings for sensitivity, specificity, and inter- and intraobserver agreement were, respectively, 94% against 75% (p less than 0.005), 91% against 91%, 86% against 79%, and 97% against 92%. In 25 patients in this group with a prior myocardial infarction, sensitivity was 100% for tomographic imaging and 92% for planar. In 27 patients without prior myocardial infarction, by contrast, sensitivity for tomographic imaging was 89% and for planar imaging 59% (p less than 0.01). Thus we conclude that both tomographic and planar imaging are highly sensitive for the detection of significant coronary artery disease, but tomographic imaging is significantly more sensitive in patients without prior myocardial infarction.

Coronary Disease↗
PubMed1981

Paradoxical ventricular tachycardia and fibrillation after intravenous bretylium therapy. Report of two cases.

Two patients were treated with bretylium tosylate for malignant ventricular arrhythmias after inadequate response to conventional agents. In the first patient, two episodes of ventricular tachycardia requiring cardioversion occurred in close temporal sequence with administering bretylium. With drug rechallenge two days later, ventricular tachycardia recurred within minutes. In the second case, five cardiac arrests due to ventricular tachycardia and fibrillation occurred during several hours after beginning a trial of bretylium maintenance therapy for complex ventricular ectopy. Although transient increases in ectopy after bretylium therapy have been described, presumably due to catecholamine release, the occurrence of life-threatening ventricular arrhythmia leading to cardiac arrest has not previously been emphasized. There is potential for this side effect, and additional caution in the use of this drug should be followed.

Adult↗
PubMed1981

Complex ventricular arrhythmias after myocardial infarction during convalescence and follow-up: a harbinger of multi-vessel coronary disease, left ventricular dysfunction and sudden death.

Sixty-one medically treated patients had coronary and left ventricular angiography and 24-hour electrocardiographic monitoring 10-24 days after myocardial infarction, and then had serial 24-hour electrocardiographic monitoring during the 13 +/- 11 months after myocardial infarction. Complex ventricular arrhythmias (2 or more sequential ventricular premature depolarizations (VPDs), multiform VPDs, bigeminy) during follow-up were associated with a high mortality rate and occurred most commonly in the setting of three-vessel coronary disease, proximal left anterior descending coronary disease and low left ventricular ejection fraction. By contrast, patients without complex VPDs in either the late hospital or posthospital phase of myocardial infarction had no mortality during the year following myocardial infarction; furthermore, these patients had a higher incidence of single-vessel coronary disease and less left ventricular dysfunction. These results emphasize the adverse prognostic significance of complex ventricular arrhythmias in the year after myocardial infarction and their association with extensive coronary artery disease and left ventricular damage.

Arrhythmias, Cardiac↗
PubMed1981

Oral hydralazine therapy for acute pulmonary embolism and low output state.

Shortly after pelvic surgery, massive bilateral pulmonary emboli and shock developed in an elderly woman. Despite fluids, dopamine hydrochloride, and heparin sodium, her condition steadily deteriorated. Two trials of hydralazine hydrochloride were given and each was associated with pronounced clinical and hemodynamic improvements. Ninety minutes and 24 hours after the first trial, her pulmonary vascular resistance decreased 44% and 67%, respectively, and cardiac index increased 40% and 90%, respectively. There were insignificant changes in heart rate and blood pressure. The hemodynamic improvements reversed when the hydralazine therapy was stopped but improved again during the second trial. Hydralazine may be of substantial benefit to patients with hemodynamic compromise secondary to pulmonary embolism.

Administration, Oral↗
PubMed1981

Myocardial imaging in man with I-123 meta-iodobenzylguanidine.

Meta-[123I]iodobenzylguanidine (m-[123I]IBG), a guanethidine analog, was used to image the myocardium in five normal male volunteers. Each subject received 2.0 mCi m-[123I]IBG intravenously. Four were given a bolus injection. Multiple myocardial scintigrams were obtained over a 2-hr period. Myocardial uptake was calculated by dividing the decay-corrected global myocardial count rate (after interpolated background correction) by the peak count rate during the first passage of the m-[123I]IBG bolus through the heart. The left ventricle could be visualized within 1-2 min of m-[123I]IBG injection. Mean myocardial uptake was 0.63% (range 0.45-0.78%) of injected dose at 5 min, and 0.76% (range 0.49-0.93%) at 2 hr (n = 4). m-[123I]IBG may provide quantitative information on myocardial catecholamine content.

3-Iodobenzylguanidine↗
PubMed1980

Thallium-201 versus technetium-99m pyrophosphate myocardial imaging in detection and evaluation of patients with acute myocardial infarction.

Thallium-201 myocardial imaging is of value in the early detection and evaluation of patients with suspected acute infarction. The extent of a thallium defect in an initial myocardial image may have important prognostic value. Tomographic imaging techniques hold promise for increased diagnostic sensitivity and more accurate quantitation of both infarcted and residual viable myocardium. Thallium imaging may have a special value in characterizing patients with cardiogenic shock and in detecting patients at risk for subsequent infarction or death or death or both, before hospital discharge. Approximately 95 percent of patients with transmural or nontransmural myocardial infarction can be detected with technetium-99m pyrophosphate myocardial imaging if the imaging is performed 24 to 72 hours after the onset of symptoms. Pyrophosphate imaging has been useful in localizing the site and determining the extent of acute myocardial infarction. The "doughnut" pattern is associated with a relatively large incidence of subsequent congestive heart failure and death. However, the clinical utility of this information is limited because it is usually not available when it is most needed, on admission to the coronary care unit. Pyrophosphate imaging may have an important role in the evaluation of patients during the early follow-up period after hospital discharge from an episode of acute infarction. The finding of a persistently positive pyrophosphate image suggests a poor prognosis and is associated with a relatively large incidence of subsequent myocardial infarction and death.

Acute Disease↗
PubMed1980

Myocardial prostaglandin E release by nitroglycerin and modification by indomethacin.

In open chest dogs, studies were made of the effects of intravenous trinitroglycerin (10 micrograms/kg per min) on circumflex arterial coronary blood flow, coronary vascular resistance, systemic arterial pressure and myocardial prostaglandin E production before and after indomethacin (n = 9) or indomethacin vehicle (n = 5). During a 30 minute trinitroglycerin infusion, coronary sinus prostaglandin E concentration increased significantly (approximately +41 percent, p less than 0.01) without significant changes in left atrial prostaglandin E concentration. After indomethacin (5 mg/kg), but not indomethacin vehicle alone, a second trinitroglycerin infusion (10 micrograms/kg per min) produced a significantly smaller decrease in coronary vascular resistance (p less than 0.05) and systemic blood pressure (p less than 0.01) and no increase in coronary sinus prostaglandin E (p less than 0.001) by comparison with control values. The heart rate response to trinitroglycerin was significantly greater (p less than 0.05) after than before indomethacin. This study suggests that the mechanism of action of trinitroglycerin may be at least partially mediated through the prostaglandin system.

Animals↗
PubMed1980

The effect of dietary supplementation of fish oil on experimental myocardial infarction.

The effect of altering the abundance of precursors and inhibitors of prostaglandin formation by dietary supplements of fish oil was investigated in dogs with experimentally induced myocardial infarction. Prior to induction, 10 male mongrel dogs were fed standard dog chow supplemented with 25% of the total calories as menhaden oil for 36 to 45 days. The fatty acid composition of th lipids in plasma and platelets changed to reflect the increased intake of polyunsaturated fatty acids of the n-3 type. Thrombosis and subsequent infarction was induced by electrical stimulation of the left circumflex coronary artery of ambulatory dogs that were monitored by telemetry. Upon stimulation of control animals, the frequency of ectopic beats rose from less than 10% at the beginning to about 80% after 19 hours. In contrast, the oil-fed dogs maintained a more normal ECG pattern, showing less than 30% ectopic beats after 19 hours. In these animals, the size of infarction (measured by formazan formation) was 3% of the left ventricle compared to 25% in the control animals. The results suggest that dietary supplementation with fish oil may be beneficial in reducing myocardial damage associated with coronary artery thrombosis.

Animals↗
PubMed1980

Radionuclide wall motion study and ejection fraction in clinical practice.

Assessment of ventricular function is important in diagnosis and as a predictor of survival in many cardiopulmonary disorders, and analysis of ventricular function is one of the oldest applications of radioactive tracers in medicine. A sequence of parallel developments in instrumentation, radiopharmaceuticals, and nuclear medicine computers has allowed implementation of accurate, sensitive, noninvasive techniques for analysis of both right and left ventricular function. Techniques, indications, applications, and information that can be obtained are discussed.

Aminophylline↗
PubMed1980

The combined approach to geriatrics and psychiatry: evaluation of a joint unit in a teaching hospital district.

A 25-bedded combined geriatric and psychogeriatric assessment unit in a District General Hospital (Teaching) is described. In the five years 1973-7 there were 1576 admissions. The turnover per bed was 12.6 per year, discharges 58% and deaths 22%. Results compare favourably with other geriatric and psychogeriatric units and with the treatment of elderly patients with psychiatric disorders in a general medical ward. The arrangement meets the needs of elderly patients very well, provides a valuable training ground, and ensures excellent liaison between geriatric and psychogeriatric services.

Age Factors↗