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Biomedical subjects

H G Olson

Publications and source records attributed to H G Olson.

At least 19 recordsLinked to original sources

Medical management of stable angina and unstable angina in the elderly with coronary artery disease.

Coronary artery disease is a major clinical problem in the elderly. This article discusses the medical management of stable and unstable angina pectoris. A review of the general measures and drug therapy used to treat these disorders, especially as they relate to the elderly patient are presented. In addition, new insights into the pathophysiologic mechanisms of chronic stable angina and unstable angina are reviewed.

Adrenergic beta-Antagonists↗

Nontraumatic sports death in high school and college athletes.

Nontraumatic deaths occur each year in organized high school and college athletics, resulting in considerable public concern. We conducted a study of the frequency and causes of nontraumatic sports deaths in high school and college athletes in the USA through the National Center for Catastrophic Sports Injury Research to define the magnitude of this problem and its causes. Over a 10-yr period, July 1983-June 1993, nontraumatic sports deaths were reported in 126 high school athletes (115 males and 11 females) and 34 college athletes (31 males and 3 females). Estimated death rates in male athletes were fivefold higher than in female athletes (7.47 vs 1.33 per million athletes per year, P < 0.0001), and twofold higher in male college athletes than in male high school athletes (14.50 vs 6.60 per million athletes per year, P < 0.0001). Cardiovascular conditions were more common causes of death than noncardiovascular conditions. Hypertrophic cardiomyopathy and congenital coronary artery anomalies were the most common causes of death. In high school and college athletes, males are at increased risk for nontraumatic sports deaths compared with females even after adjustment for participation frequency; college males are at greater risk than high school males. In all groups the deaths were primarily due to cardiovascular conditions.

Adolescent↗

Bedside cardiology and thrombolysis.

The study by Christian et al. (37) provides useful clinical information for the management of the patient with myocardial infarction with thrombolytic therapy. 1) Complete resolution of chest pain during the infusion of an intravenous thrombolytic agent suggests reperfusion and myocardial salvage. Initial conservative medical management should be considered in these patients especially if serial ECGs show a progressive and rapid downward defection of the ST segment. 2) Patients presenting within 6 h after the onset of infarction, who are pain free, may still benefit from thrombolysis if their ECGs show persistent ischemia. 3) In the remaining patients in whom chest pain does not resolve completely during thrombolytic therapy, management, whether continued medical or invasive strategy, should be individualized and dictated by the extent of myocardium at risk (i.e., by the number of ECG leads showing ST segment elevation), the response of the ST segment to thrombolysis and, most important, the clinical status of the patient.

Angina Pectoris↗

Catheter optimization during contrast ventriculography: a prospective randomized trial.

Although newer contrast mediums have improved hemodynamic stability during left ventriculography, the image quality and hence the diagnostic yield of the procedure is largely determined by the choice of catheter and injection technique. In this study 125 patients were prospectively assigned at random to undergo ventriculography using either of two pigtail catheters, one with a straight shaft throughout its length (straight) and one with a 145-degree bend placed 6.5 cm from the distal end (angled). Injectate composition, flow rate, and volume were held constant for all injections, and baseline clinical and catheterization variables were found to be similar in each group. The angled catheter exhibited a statistically superior ease of insertion (p = 0.038) and took less time to position (p = 0.012), saving a mean of 23 seconds of fluoroscopy time per procedure. It was also associated with superior contour edge definition (p = 0.037) and a trend toward more uniform distribution of contrast medium (p = 0.089). Compared with the straight catheter, the angled catheter was less frequently accompanied by artifactual mitral regurgitation (p = 0.038) but was equally likely to provoke ventricular arrhythmias during injection. These observed differences may be explained in part by the tendency for angled catheters to more frequently localize in the central as opposed to the inferoposterior region of the left ventricular cavity (mean distance from center = 0.53 vs 1.10 cm, respectively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Etiology and prognostic implications of a large pericardial effusion in men.

To assess the etiology and prognosis of a large pericardial effusion, we reviewed 25 consecutive patients who presented with a large pericardial effusion and underwent a drainage procedure. Large pericardial effusion was defined as: (1) an echo-free space greater than or equal to 10 mm anteriorly and posteriorly by M-mode echocardiography and (2) removal of greater than or equal to 350 ml of fluid at pericardial drainage. The etiologies of large pericardial effusion were: neoplastic (36%), idiopathic (32%), uremic (20%), postmyocardial infarction (8%), and acute rheumatic fever (4%). Of our patients, 44% presented with cardiac tamponade, while 25% of patients with idiopathic pericarditis had hemorrhage effusion and cardiac tamponade. At follow-up, 37 +/- 17 months after pericardial drainage, 68% had died from complications of their underlying disease. There were no deaths attributed to pericardial disease. While 88% of patients with idiopathic large pericardial effusion were alive at follow-up, none of the neoplastic large pericardial effusion patients survived longer than 5 months after initial pericardial drainage (p less than 0.001). Additionally, the survival of patients with uremic large pericardial effusion was better than patients with neoplastic large pericardial effusion (p less than 0.05). We conclude: (1) neoplastic, idiopathic, and uremic pericarditis are the most common causes of large pericardial effusion in men, (2) idiopathic pericarditis can be hemorrhagic and cause cardiac tamponade, and (3) the prognosis of large pericardial effusion is related to patients' underlying disease.

Adult↗

Effect of beta-adrenergic blockade on exercise performance in patients with chronic atrial fibrillation.

Beta-adrenergic blocking agents are commonly used in combination with digitalis to control excessive heart rate during exercise in patients with chronic atrial fibrillation. However, little is known about the effect of beta-adrenergic blockade on exercise capacity in these patients. Accordingly, a randomized, double-blind, cross-over placebo-controlled study was performed to assess the efficacy of celiprolol, a new cardioselective beta-blocker with partial intrinsic sympathomimetic activity, on exercise performance in nine men with chronic atrial fibrillation. All but one patient was receiving maintenance digitalis during the study. Heart rate, blood pressure and gas exchange variables were measured at rest and during treadmill exercise testing while the patients were receiving maintenance celiprolol or placebo. Significant reductions in heart rate and systolic blood pressure compared with control values were observed at submaximal exercise, at the gas exchange anaerobic threshold and at maximal exertion while the patients were taking celiprolol. However, oxygen uptake at the gas exchange anaerobic threshold during celiprolol therapy was 12.3 versus 14.0 ml oxygen/kg per min during placebo administration (a 12% difference, p less than 0.01). Similarly, oxygen uptake at maximal exertion during celiprolol therapy was 17.6 versus 21.0 ml/kg per min during placebo administration (a 16% difference, p less than 0.01). Treadmill time was also reduced during the celiprolol phase compared with placebo (11.3 versus 10.3 minutes; a 19% difference, p less than 0.01). These results indicate that in patients with atrial fibrillation the major beneficial effects of beta-adrenergic blockade--reduced submaximal and maximal exercise heart rate and blood pressure--must be weighed against the decrease in exercise capacity.

Adrenergic beta-Antagonists↗

Myocardial infarct imaging in patients with technetium-99m 2,3-dimercaptosuccinic acid. Superiority of technetium-99m pyrophosphate.

Technetium-99m 2,3-dimercaptosuccinic acid (Tc-99m DMSA) has been used successfully for imaging acute myocardial infarction in a canine model. The application in humans, however, has not been previously reported. In order to determine the feasibility of using this agent in clinical studies and to compare the agent to technetium-99m pyrophosphate (Tc-99m PPi), ten patients with proven myocardial infarction were studied. While imaging of transmural infarctions in humans was achieved using Tc-99m DMSA, scores for the Tc-99m DMSA images (1.8 +/- 0.96) were not as high as for Tc-99m PPi (2.5 +/- 0.45) (P less than 0.05). Discordance among four independent interpreters was greater for images obtained with Tc-99m DMSA. The superiority of Tc-99m PPi was evident whether images were obtained early (within 24 hours) or late (within five days). Although DMSA images were not obscured by rib uptake, they were less sensitive (63%) than Tc-99m PPi (97%). A potential advantage of Tc-99m DMSA in imaging acute myocardial infarction is that radiotracer concentration in the infarct occurs primarily in the early postinfarction period. The longer postinfarction that Tc-99m DMSA imaging was attempted, the lower the concentration of radiotracer. Thus, Tc-99m DMSA would not be expected to have the same persistence pattern as Tc-99m PPi into the remote postinfarction period. The persistent positivity of Tc-99m PPi has made it difficult to diagnose reinfarction.

Aged↗

A randomized controlled trial of intravenous streptokinase in evolving acute myocardial infarction.

To determine the efficacy of intravenous streptokinase in acute myocardial infarction, 52 patients were randomized to intravenous streptokinase or control groups. Time from onset of infarction to randomization was similar in the streptokinase group and control group, 4.9 +/- 2.1 hours vs 5.4 +/- 2.4 hours, respectively. The 28 streptokinase patients received an intravenous infusion of 700,000 units of streptokinase followed by full-dose anticoagulation. The 24 control patients received normal saline solution followed by full-dose anticoagulation. Of 28 streptokinase patients, 12 (43%) had noninvasive evidence of reperfusion by early peaking of serum creatine kinase (peak creatine kinase less than 16 hours after onset of infarction) vs 3 of 24 control patients (13%), p less than 0.02. Two streptokinase patients (7%) had reperfusion arrhythmias during streptokinase infusion. One streptokinase patient (4%) and two control patients (8%) died during hospitalization. At angiography (16 +/- 5 days after infarction) 22 of 26 streptokinase patients (85%) had a patent infarct-related coronary artery compared to 8 of 20 control patients (40%), p less than 0.01. Comparison of radionuclide left ventricular ejection fraction assessed acutely (28 +/- 10 hours after infarction) with left ventricular ejection fraction at hospital discharge (15 +/- 3 days after infarction) showed no significant improvement in either the streptokinase or control group, 0% and +1%, respectively. At follow-up 13 +/- 7 months after infarction, total mortality rate was similar in the streptokinase group and control group, 17.8% (5 of 28 streptokinase patients) and 20.8% (5 of 24 control patients), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Early exercise testing after stabilization of unstable angina: correlation with coronary angiographic findings and subsequent cardiac events.

To evaluate the safety and diagnostic use of exercise testing in patients with unstable angina, 78 patients underwent submaximal exercise testing and diagnostic cardiac catheterization early after stabilization of their pain. Thirty-six patients (46%) had a positive exercise test manifested as angina or ST segment depression of greater than or equal to 0.1 mV during or immediately after exercise. Thirty-three of 36 patients (92%) with a positive exercise test had multivessel coronary disease compared to 18 of 42 patients (43%) with a negative exercise study (p less than 0.001). Twenty-two of 36 patients (61%) with a positive exercise test had three-vessel disease compared to 12 of 42 patients (29%) with a negative test (p = 0.004). The sensitivity of exercise testing in detecting multivessel disease was 65%, specificity 89%, predictive value of a positive test 92%, predictive value of a negative test 57%, and overall accuracy 73%. When the 42 patients taking beta blockers were examined, these values were essentially unchanged. Ventricular arrhythmias during exercise testing were associated with a lower ejection fraction, 61.1 +/- 12.5%, compared to 67.9 +/- 11.1% in patients without ventricular arrhythmias (p less than 0.05). Submaximal exercise testing after stabilization of patients with unstable angina is safe and useful in evaluating patients for the presence of multivessel coronary artery disease.

Adult↗

Effect of coffee on exercise-induced angina pectoris due to coronary artery disease in habitual coffee drinkers.

The acute effects of coffee on exercise-induced angina were studied in 17 men with coronary artery disease using a double-blind treadmill protocol. Ingestion of either 1 or 2 cups of caffeinated coffee increased the exercise duration until onset of angina (8 and 12%, respectively, p less than 0.05), whereas decaffeinated coffee had no effect. The extent of ST-segment depression and the heart rate-blood pressure product at angina were similar after drinking caffeinated and decaffeinated coffee. Exercise duration until 0.1 mV of ST-segment depression, as well as the heart rate, blood pressure and double product at angina and at 0.1 mV of ST-segment depression were similar after drinking caffeinated or decaffeinated coffee. The mean serum caffeine levels (+/- standard deviation) after ingestion of 1 and 2 cups of caffeinated coffee were 1.97 +/- 1.0 and 3.89 +/- 1.6 micrograms/ml, respectively. The acute ingestion of 1 to 2 cups of caffeinated coffee had no deleterious effect on exercise-induced angina pectoris in patients with coronary artery disease.

Adult↗

Hemodynamic effects of verapamil in left ventricular valvular volume overload.

The hemodynamic consequences of aortic and mitral insufficiency may be influenced by the high systemic vascular resistance often seen in these patients. Since the calcium antagonists have been shown to reduce systemic vascular resistance, we evaluated the effects of intravenous verapamil in 23 patients. In 11 patients with aortic insufficiency, verapamil resulted in a 20% increase in cardiac index (p less than 0.001), 18% increase in forward stroke volume index (p less than 0.001), and a 24% decrease in regurgitant fraction (p less than 0.005). In the 12 patients with mitral insufficiency, verapamil resulted in a 19% increase in both cardiac index (p = 0.004), and forward stroke volume index (p less than 0.001), while there was a 19% decrease in regurgitant fraction (p less than 0.02). Left ventricular end-systolic stress decreased significantly in both groups as did end-diastolic stress in the mitral insufficiency group. There was no significant change in several measures of contractile performance, though the end-systolic stress-to-volume index ratio fell significantly (p less than 0.04) in the mitral insufficiency group. Our findings suggest that the vasodilatory effects of intravenous verapamil predominate over the negative inotropic effects in patients with aortic and mitral insufficiency. Verapamil may be of use in patients intolerant to other vasodilators, patients with concomitant ischemic heart disease, or those with supraventricular arrhythmias.

Aortic Valve Insufficiency↗

Prognostic implications of complicated ventricular arrhythmias early after hospital discharge in acute myocardial infarction: a serial ambulatory electrocardiography study.

To assess the prevalence and prognostic implications of complicated ventricular ectopic depolarizations (VEDs) after hospital discharge in patients with acute myocardial infarction (AMI), we obtained serial 24-hour Holter recordings in 85 patients during the first 6 weeks after AMI. Recordings were obtained during two coronary care unit time intervals, two hospital ward time intervals, and during four weekly time intervals after discharge. Complicated VEDs were defined as unifocal VEDs greater than or equal to 10/1000 beats for 24 hours, multiform VEDs, pairs, or ventricular tachycardia. At 1 year follow-up, there were nine cardiac deaths (six sudden deaths and three deaths from recurrent AMI). The mean left ventricular ejection fraction at discharge in the cardiac death patients was 29 +/- 12% (sudden death patients 24 +/- 11% and AMI death patients 40 +/- 6%) compared to 49 +/- 13% in the survivors (p less than 0.001). Patients with complicated VEDs at discharge (2 weeks after AMI) or during the first 4 weeks after discharge (3 to 6 weeks after AMI) were significantly more likely to have sudden death at follow-up compared to patients without complicated VEDs. Of the six sudden death patients, four (66%) had complicated VEDs at discharge compared to 18 of 68 survivors (26%) (p less than 0.05). One of three patients who died of recurrent AMI had complicated VEDs. No Holter data were obtained at hospital discharge in eight of the survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Submaximal exercise testing after stabilization of unstable angina pectoris.

To determine the prognostic value of exercise testing in patients with unstable angina pectoris, 125 hospitalized patients were prospectively evaluated soon after stabilization of their pain. Exercise testing was performed after exclusion of acute myocardial infarction and a pain-free period of at least 3 days (mean +/- SD 3.9 +/- 1.4). No complications were noted during or immediately after exercise testing. A positive test (angina or greater than or equal to 1 mm ST segment depression, or both) was noted in 60 patients (48%). During a 1 year follow-up period, 52 (87%) of these 60 patients had an unfavorable outcome (American Heart Association class III or IV angina, recurrent unstable angina, coronary artery bypass surgery, acute myocardial infarction or cardiac death) compared with 19 (29%) of the 65 patients with a negative test (p less than 0.001). The sensitivity and specificity of exercise testing in predicting outcome were 73 and 85%, respectively. The predictive value of a positive test was 87% and that of a negative test was 71%. Angina by itself during the exercise test was a reliable predictor of severe angina (class III or IV angina) at follow-up (sensitivity 92%, specificity 89%, positive predictive value 83% and negative predictive value 95%; p less than 0.001). The findings were not significantly affected by beta-adrenergic blocking agents or digitalis in the study sample. Thus, in patients with unstable angina which has been stabilized, the results of early submaximal exercise testing may be useful in predicting outcome in the first year after hospital discharge. Patients with a positive test result should be considered for further diagnostic studies.

Adult↗

Validation of technetium-99m stannous pyrophosphate myocardial scintigraphy for diagnosing acute myocardial infarction more than 48 hours old when serum creatine kinase-MB has returned to normal.

Determination of lactic dehydrogenase (LDH) isoenzymes is the current method of choice for diagnosing acute myocardial infarction (AMI) greater than 48 hours old. However, other causes of enzyme elevation make the availability of an alternate method of diagnosis worthwhile. Accordingly, serial technetium-99m pyrophosphate scintigrams were obtained in 61 patients with transmural AMI and in 46 patients with subendocardial AMI. Imaging was performed in all 107 patients at the time creatine kinase isoenzyme (CK-MB) was present 37 +/- 18 hours (range 12 to 72) after the onset of AMI, and at the time CK-MB was absent 106 +/- 34 hours (range 48 to 168) after the onset of AMI. At the time CK-MB was absent, the sensitivity using either a regional or a diffuse positive scintigram was 95% (58 of 61 patients) for transmural AMI and 65% (30 of 46 patients) for subendocardial AMI. The sensitivity using a regional positive scintigram was 82% (50 of 61 patients) for transmural AMI and 37% (17 of 46 patients) for subendocardial AMI. The sensitivity using a high-grade regional positive scintigram was 36% (22 of 61 patients) for transmural AMI and 11% (5 of 46 patients) for subendocardial AMI. The specificity was 70% (143 of 204 patients) for either a regional or a diffuse abnormality, 92% (187 of 204 patients) for a regional abnormality, and 100% (204 of 204 patients) for a high-grade regional abnormality. Thus, pyrophosphate scintigraphy is useful in confirming the diagnosis of AMI, particularly transmural, greater than 48 hours old and when CK-MB has returned to normal. A positive scintigram with a high-grade regional abnormality is specific for a recent AMI and may be contributory in establishing the diagnoses when LDH isoenzymes are inconclusive.

Adult↗

The high-risk angina patient. Identification by clinical features, hospital course, electrocardiography and technetium-99m stannous pyrophosphate scintigraphy.

We evaluated 193 consecutive unstable angina patients by clinical features, hospital course and electrocardiography. All patients were managed medically. Of the 193 patients, 150 (78%) had a technetium-99m pyrophosphate (Tc-PYP) myocardial scintigram after hospitalization. Of these, 49 (33%) had positive scintigrams. At a follow-up of 24.9 +/- 10.8 months after hospitalization, 16 of 49 patients (33%) with positive scintigrams died from cardiac causes, compared with six of 101 patients (6%) with negative scintigrams (p less than 0.001). Of 49 patients with positive scintigrams, 11 (22%) had had nonfatal myocardial infarction at follow-up, compared with seven of 101 patients (7%) with negative scintigrams (p less than 0.01). Age, duration of clinical coronary artery disease, continuing angina during hospitalization, ischemic ECG, cardiomegaly and a history of heart failure also correlated with cardiac death at follow-up. Ischemic ECG and a history of angina with a crescendo pattern also correlated with nonfatal infarction at follow-up. Patients with continuing angina, an ischemic ECG and a positive scintigram constituted a high-risk unstable angina subgroup with a survival rate of 58% at 6 months, 47% at 12 months and 42% at 24 and 36 months. We conclude that the assessment of clinical features, hospital course, ECG and Tc-PYP scintigraphy may be useful in identifying high-risk unstable angina patients.

Acute Disease↗