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Biomedical subjects

R M Gunnar

Publications and source records attributed to R M Gunnar.

At least 55 records · Page 3Linked to original sources
PubMed1983

Shock in acute myocardial infarction: evolution of physiologic therapy.

In the past 25 years the treatment of shock in myocardial infarction has evolved into a physiologic approach based on on-line measurements of hemodynamic variables. This has aided in the development of new pressor agents so that a family of pharmacologic agents is now available. Appropriate use of vasodilators and recognition and treatment of intravascular volume depletion have increased survival. Recognition and appropriate treatment of the preshock state have decreased the incidence of shock. The criteria for use of mechanical support and surgical intervention are soundly established; the use of thrombolytic therapy and balloon angioplasty for this syndrome is ready to be evaluated.

Dobutamine↗
PubMed1983

Beneficial effects of dopamine combined with intravenous nitroglycerin on hemodynamics in patients with severe left ventricular failure.

Hemodynamic effects of dopamine and intravenous nitroglycerin alone, and in combination, were studied in 27 patients with severe left ventricular failure. Dopamine alone increased cardiac index from 1.8 to 2.5 l/min/m2 but also increased wedge pressure from 24 to 30 mm Hg and heart rate from 88 to 101 beats/min. Arterial oxygen saturation fell from 92% to 87% (p less than .001). Nitroglycerin alone had a lesser effect on cardiac index (1.8 to 2.2 l/min/m2) but decreased wedge pressure from 26 to 16 mm Hg and heart rate from 91 to 86 beats/min. Arterial oxygen saturation fell from 91% to 90% (NS). Combined dopamine and nitroglycerin administration resulted in optimal hemodynamics, with cardiac index of 2.9 l/min/m2, wedge pressure of 17 mm Hg, and heart rate of 96 beats/min. Arterial oxygen saturation remained low at 88% in spite of the reduction in left ventricular filling pressure, which probably reflects increased intrapulmonary right-to-left shunting coupled with increased pulmonary blood flow. These results suggest that the combination of dopamine with intravenous nitroglycerin should be considered for patients with severe left ventricular dysfunction who require temporary pharmacologic support.

Adult↗
PubMed1983

Management of left ventricular rupture complicating myocardial infarction.

Rupture of the left ventricle secondary to myocardial infarction may occur more often than is suspected. More time than anticipated may be available between rupture and catastrophic deterioration. Hemodynamic stabilization, diagnostic studies, and surgical treatment can be successfully undertaken. Four patients have been successfully treated in our institution. Rupture occurred from 1 to 14 days after infarction. Persistent chest pain was present in all. All were hemodynamically unstable and all stabilized with counterpulsation. One patient was in cardiogenic shock, two had a cardiac arrest, and one presented with cardiac tamponade requiring two emergency pericardiocenteses. Coronary arteriography was done in all four patients. Surgical management consisted of infarctectomy and repair of the ventricular rupture. Additionally, a single aortacoronary bypass graft was needed in two patients and repair of a ventricular septal rupture was necessary in a third. There was no operative mortality. One patient drowned 1 year later. We conclude that successful surgical management requires (1) suspicion of ventricular rupture, (2) hemodynamic stabilization by counterpulsation, (3) coronary arteriography, and (4) combined infarctectomy and repair with revascularization.

Aged↗
PubMed1982

Transient bundle branch block following use of hypothermic cardioplegia in coronary artery bypass surgery: high incidence without perioperative myocardial infarction.

Hypothermic cardioplegia (HCP) is a method commonly used for myocardial preservation at the time of aortic cross-clamping during coronary artery bypass grafting (CABG). This study assessed the frequency and significance of transient bundle branch block (BBB) in 50 patients undergoing CABG using HCP compared to 61 controls. All patients had normal QRS complexes on preoperative ECG. CLinical, hemodynamic, and operative data were similar in both groups. Seventeen (34%) of the HCP group and four (6%) of the controls developed postoperative BBB (p less than 0.001). These changes were transient in all but three patients in the HCP group. None of the HCP patients with transient BBB had evidence of perioperative myocardial infarction. Clinical and operative parameters did not provide prediction of development of transient BBB. This study demonstrates that transient BBB in the immediate post-CABG period occurs commonly with the use of HCP and does not indicate myocardial necrosis.

Aged↗
PubMed1982

Risk factors related to progressive narrowing in aortocoronary vein grafts studied 1 and 5 years after surgery.

Factors related to late narrowing of aortocoronary vein grafts are poorly understood. Repeat aortocoronary bypass graft angiography was performed in 34 patients at 13 +/- 5 months and 61 +/- 13 months after surgery. In these patients, 61 of 65 grafts (94%) were patent at 1 year; at 5 years, 39 of these patent grafts (64%) remained unchanged, 21 (34%) had become progressively narrowed and one (2%) was totally occluded. There appeared to be no predilection for progression to occur at specific segments or in particular grafts: Eight of 28 left anterior descending (29%), seven of 17 right coronary artery (41%) and seven of 16 circumflex artery grafts (44%) (NS) showed further narrowing. Progressive graft narrowing occurred in 15 of 34 patients (44%). Risk factors (incidence of smoking, diabetes mellitus, hypertension, and triglyceride and cholesterol levels) in these 15 patients were compared with those in the 19 patients whose grafts were unchanged between 1 and 5 years. The incidence of smoking, diabetes mellitus (fasting blood sugar greater than or equal to 110 mg % or 2-hour postprandial sugar greater than or equal to 140 mg %) and hypertension (systolic blood pressure greater than 140 mm Hg or diastolic pressure greater than or equal to 95 mm Hg) were 46%, 27% and 33%, respectively, in the patients with progressive graft narrowing and 68%, 16%, 26% in the patients whose grafts were unchanged (NS). The average mean triglyceride levels were 617 +/- 785 mg % (+/- SD) and 195 +/- 86 mg %, respectively (p less than 0.05). The average mean cholesterol levels were 279 +/- 53 mg % and 234 +/- 35 mg %, respectively (p less than 0.01). In patients who have had aortocoronary bypass surgery, total graft occlusion is rare between 1 and 5 years after surgery. Progressive narrowing of grafts is common and appears to be associated with elevated blood lipids.

Cholesterol↗
PubMed1981

Diagnosis of dissecting aortic aneurysm by computed tomography.

Computed tomography (CT) of the torso combined with simultaneous intravenous bolus injection of contrast media was used in sixteen patients suspected of having dissected their aorta. All patients had subsequent correlative percutaneous aortography within 24 h of the CT examination. Four patients proved to be normal, one had an aneurysm of the thoracic aorta, and eleven had aortic dissection (five type I, six type III dissection). All eleven patients with aortic dissections were diagnosed by CT and angiography; nine had spontaneous dissections and two had iatrogenic injuries to the aorta. Limitations of this imaging procedure include; inability to detect aortic valvular dysfunction and failure to provide an adequate perspective of aortic branch involvement. Potential benefits include: avoidance of aortogram in some cases, relative non-invasiveness, rapidity and ease of procedure, and less expense, radiation, contrast media, and discomfort to the patient. Early experience with CT-enhancement technique has reliably demonstrated normal as well as abnormal aortic wall morphology. It may have a place as an alternative to the conventional aortogram.

Adult↗
PubMed1981

Immunosuppressive therapy in patients with congestive cardiomyopathy and myocardial uptake of gallium-67.

Thirty-nine patients with idiopathic congestive cardiomyopathy underwent gallium-67 scintigraphy. Twenty had no evidence of myocardial uptake (group I) and 19 had demonstrable myocardial gallium-67 activity (group II). There was no significant difference in age, sex, duration of symptoms, antecedent viral illness, left ventricular end-diastolic pressure, pulmonary artery systolic pressure, or ejection fraction between the two groups. Fifteen patients in group II were treated with prednisone and azathioprine for a minimum of 8 months. Nine of 15 patients were clinically unchanged and gallium-67 scans remained positive (group IIa). Six patients had significant improvement and resolution of myocardial gallium-67 uptake (group IIb). The mean change in ejection fraction was +0.2% in group I, -4.8% in Group IIa, and +13.8% in group IIb. There were five deaths in group I (25% mortality), three in group IIa (33% mortality), and no deaths in group IIb. The only significant difference between patients in group IIa and those in group IIb was a greater left ventricular posterior wall thickness in group IIa patients. Twenty control patients without cardiac disease had negative gallium-67 scans. We conclude that gallium-67 myocardial scintigraphy may be a useful test for predicting the response to prednisone and azathioprine therapy.

Adolescent↗
PubMed1981

Progression of coronary artery disease in medically and surgically treated patients 5 years after randomization.

Repeat angiography was performed at 63 +/- 9 months in 26 medically treated patients and at 66 +/- 10 months in 32 surgically treated patients with chronic angina. The native coronary arteries were divided into three major trunk vessels and 15 angiographic segments. Progression of disease was defined as the appearance of new (greater than 50%) obstruction or significant worsening of existing lesions in a segment or vessel. The incidence of progression was similar in medical and surgical patients, comparing individual segments (69 of 312 [22%] and 91 of [23%], respectively) or vessels (49 of 78 [63%] and 60 of 96 [63%], respectively). In both medical and surgical patients, segments initially free of disease showed a 14% incidence of developing new lesions, compared with the 37% progression in segments initially diseased (p less than 0.001). In the surgical patients, progression occurred in 48 of 219 (22%) nongrafted and 43 of 177 (24%) grafted segments (NS). When analyzed by major trunk vessel, progression occurred in 40 of 57 grafted arteries (70%) and 20 of 39 nongrafted arteries (51%) (NS). The incidence of new total occlusions was similar in medical and surgical patients (6% and 8%, respectively); new total occlusions occurred predominantly in diseases segments (15% and 22%, respectively). In patients with stable angina pectoris who have medical or surgical treatment assigned by randomization, progression of coronary disease at 5 years is not influenced by which mode of therapy was received. Vessels initially free of disease are at relatively low risk for development of disease within 5 years. In surgical patients, grafted and nongrafted vessels show similar rates of progression.

Angiography↗
PubMed1980

Comparative effect of intravenous dipyridamole and sublingual nitroglycerin on coronary hemodynamics and myocardial metabolism at rest and during atrial pacing in patients with coronary artery disease.

The effects of intravenous dipyridamole (20 mg) and sublingual nitroglycerin (0.6 mg) were compared at rest and during rapid atrial pacing in patients with significant coronary obstruction. Dipyridamole, which had no significant effect on resting systolic blood pressure, caused a significant increase in coronary sinus flow (CSF) and reduction of coronary vascular resistance (CVR) and arterial-coronary sinus oxygen difference (AO2CSO2 delta), whereas nitroglycerin reduced resting systolic pressure but had no significant effect on CSF, CVR, or AO2-CSO2 delta. Although theses effects of dipyridamole and nitroglycerin on resting systolic pressure, CSF, CVR, and AO2-CSO2 delta were qualitatively similar during rapid atrial pacing, the onset of chest pain and ischemic ECG changes occurred at a lower heart rate following dipyridamole (136 +/- 5 beats/min) than following nitroglycerin (149 +/- 6 beats/min, p less than 0.01). However, maximal double product and myocardial oxygen consumption achieved during pacing were similar following both dipyridamole and nitroglycerin and were less than control pacing values. Coronary dilatation following dipyridamole appears to reduce tolerance to pacing-induced ischemia probably by maldistribution of coronary flow away from ischemic myocardium. Nitroglycerin differs from dipyridamole by improving tolerance to pacing; however, this difference appears to be due to systemic vasodilator effects of nitroglycerin rather than to enhancement of flow to ischemic myocardium.

Aged↗
PubMed1980

Gallium-67 citrate scanning for noninvasive detection of inflammation in pericardial diseases.

The treatment of acute nonspecific pericarditis is controversial. No study is available that confirms the efficacy of the administration of corticosteroids or nonsteroid anti-inflammatory agents in this condition. There is no reliable invasive marker for pericardial inflammation, because echocardigraphy demonstrates only the presence of fluid. In four patients with pericarditis, gallium-67 citrate scanning was performed, and the isotope was localized to the cardiac silhouette in all. In one patient with effusion the gallium scan was positive and then reverted to negative with corticosteroid therapy. In another, the gallium scan remained positive despite resolution of the pericardial effusion with corticosteroid therapy. This patient eventually required pericardial stripping. Pericardial localization of gallium was useful in detecting the cause of fever in a patient after aortocoronary bypass grafting and in detecting pericardial involvement in a patient with multisystem viral disease. Pericardial localization of gallium-67 may be diagnostically useful and may provide a proper control for the study of the efficacy of corticosteroids versus nonsteroid anti-inflammatory agents in pericarditis.

Adolescent↗