Cardiac chronotropic responsiveness to beta-adrenoceptor stimulation is not reduced in the elderly

OBJECTIVES

This study evaluated cardiac beta-adrenoceptor responsiveness in the elderly.

BACKGROUND

The hypothesis of reduced cardiac beta-adrenoceptor responsiveness in the elderly is based on a smaller increase in heart rate after administration of isoproterenol, a nonselective beta 1- and beta 2-adrenoceptor agonist. By means of dobutamine-stress-echocardiography we were able to retest the hypothesis more accurately because dobutamine is a relatively selective beta 1-adrenoceptor agonist with weak beta 2- and alpha-adrenoceptor stimulant activity that prevents baroreflex-mediated changes in heart rate.

METHODS

After administration of stepwise incremental infusions of dobutamine, we measured heart rate and blood pressure responses in 360 patients who had no beta-adrenergic blocking agent therapy and no side effects during the stress test. For each patient we calculated the dose of dobutamine required to increase heart rate by 50% of the maximal heart rate during the highest dose of dobutamine.

RESULTS

No relation was found between age and sensitivity to dobutamine (n = 293). Power analysis revealed that this negative finding was not the result of inadequate sample size. In contrast to the prevailing hypothesis, an increased heart rate response to dobutamine was found even in a subgroup of "healthy" elderly subjects (i.e., those without concomitant disease or acute myocardial ischemia, n = 67) that was not related to changes in blood pressure during stress. However, in subjects with acute ischemia (n = 109), smokers (n = 151) or patients with a history of a previous myocardial infarction (n = 148), dobutamine sensitivity was reduced in the elderly despite a diminished change in systolic blood pressure with advanced age during dobutamine infusion. This phenomenon could be explained by a decrease in efferent cardiac baroreflex sensitivity, as has been observed during acute myocardial ischemia. There were no age-related differences in plasma concentrations of dobutamine.

CONCLUSIONS

No evidence for reduced beta-adrenoceptor responsiveness to dobutamine was found in "healthy" elderly subjects.

Dobutamine-atropine stress echocardiography in elderly patients unable to perform an exercise test. Hemodynamic characteristics, safety, and prognostic value

OBJECTIVE

To establish the hemodynamic effects, safety, and prognostic value of dobutamine-atropine stress echocardiography in patients 70 years of age or older.

DESIGN AND SETTING

Observational study at a university hospital.

PATIENTS

One hundred seventy-nine patients (mean age, 75 years; range, 70 to 90 years) referred for chest pain (n = 73) or preoperative risk assessment for major vascular noncardiac surgery (n = 106).

MEASUREMENTS

All patients underwent clinical evaluation and dobutamine-atropine stress test.

RESULTS

One hundred seventy-nine stress tests were performed. Test end points were the target heart rate (85% of theoretical maximum heart rate), reached in 165 tests (92%); inadequate echo images, two tests (1%); and side effects, 12 tests (7%). Side effects that caused a premature end of the test were severe chest pain (n = 5 [2.8%]), electrocardiographic changes (n = 1 [0.6%]), hypotension (n = 2 [1.1%]), chills (n = 2 [1.1%]), and cardiac arrhythmias (paroxysmal atrial fibrillation) (n = 2 [1.1%]). New wall motion abnormalities as a marker of myocardial ischemia occurred in 50 tests (28%). No death or myocardial infarction occurred during the test. Perioperative events occurred in 12 patients (four cardiac deaths, three myocardial infarctions, and five episodes of unstable angina). During 16 +/- 6 months (mean +/- SD) of follow-up of 166 patients, 22 cardiac events occurred (eight cardiac deaths, four myocardial infarctions, and 10 episodes of unstable angina pectoris). By multivariate regression analysis, only perioperative cardiac events (odds ratio, 51; 95% confidence interval, 5.8 to 454) and late cardiac events (odds ratio, 5.2; 95% confidence interval, 2.0 to 14) were correlated with new wall motion abnormalities during stress.

CONCLUSION

Dobutamine-atropine stress echocardiography is a feasible and safe test for assessing elderly patients with suspected and/or proven coronary artery disease, providing useful prognostic information for perioperative and late cardiac risk with relatively few side effects.

Dobutamine-atropine stress echocardiography and clinical data for predicting late cardiac events in patients with suspected coronary artery disease

PURPOSE

To compare the relative value of clinical variables with dobutamine-atropine stress echocardiography to predict cardiac events during long-term follow-up. Dobutamine stress echocardiography is increasingly used for the detection of coronary artery disease, but little is known of its prognostic value.

PATIENTS AND METHODS

A total of 430 patients (310 men; mean age 61 years, range 22 to 90) were enrolled in the study. Patients were referred for chest pain complaints and were unable to perform an adequate exercise stress test. All patients underwent dobutamine-atropine stress test (incremental dobutamine infusion: 10 to 40 micrograms/kg/minute, continued with atropine 0.25 to 1 mg intravenously if necessary to achieve 85% of the age predicted maximal heart rate, without symptoms or signs of ischemia) and clinical cardiac evaluation. Follow-up was 17 +/- 5 months, with a minimum of 6 months; 3 patients were lost to follow-up. Cardiac events were defined as cardiac death, nonfatal myocardial infarction, and coronary revascularization.

RESULTS

Seventy-nine cardiac events occurred in 76 patients: cardiac death (n = 11), nonfatal myocardial infarction (n = 18), and coronary revascularization (n = 50). By multivariate regression analysis, the prognostic value of the stress test in addition to common clinical variables was assessed. (1) Cardiac death was predicted by age greater than 70 years (odds ratio 5.6, 1.5 to 20) or new wall motion abnormalities in a study that is normal at rest (odds ratio 4.1, 1.1 to 15). (2) Death or myocardial infarction was predicted by a history of myocardial infarction (odds ratio 4.8, 1.8 to 13) or age greater than 70 years (odds ratio 2.3, 1.1 to 5.4), and the stress test outcome provided no additional information. (3) If all events were combined, only stress test results were prognostic: new wall motion abnormalities in a study that is normal at rest (odds ratio 3.1, 1.9 to 5.1), wall motion abnormalities at rest (wall motion score at rest > or = 1.12) (odds ratio 2.5, 1.4 to 4.0), or any new wall motion abnormalities during stress (odds ratio 2.0, 1.4 to 3.8). The positive predictive value of any new wall motion abnormality during stress for all late cardiac events was 25% (95% confidence interval [CI] 19 to 31) with a negative predictive value of 87% (95% CI 83 to 91).

CONCLUSION

In a large cohort of unselected patients with chest pain syndromes, new wall motion abnormalities induced by dobutamine provide additional information for late cardiac events, independent of clinical variables.

[Stress echocardiography: 4 years of experience at the Thoraxcenter]

In this article, we report the experience on stress echocardiography at the Thoraxcenter of Erasmus University of Rotterdam in the years 1990-1994. Different types of stress have been used in conjunction with ultrasound techniques. The results have been compared with other non-invasive methods (exercise ECG testing, myocardial perfusion scintigraphy with single photon emission computed tomography) and with coronary arteriography. Both the diagnostic and prognostic value of stress echocardiography have been assessed in different clinical situations, as in patients with chest pain and suspected or proven coronary artery disease, patients referred for percutaneous transluminal coronary angioplasty, patients referred for major non cardiac vascular surgery. After this period of validation, stress echocardiography has now a definite role in the clinical decision making for the evaluation of myocardial ischemia. The assessment of viable myocardium, especially in patients with advanced left ventricular dysfunction, is one of the major topic currently under investigation. Practical aspects of the interpretation of the tests, costs and organization of the stress echo laboratory, indications and newest research applications are also discussed.

Dobutamine-atropine stress echocardiography for assessment of perioperative and late cardiac risk in patients undergoing major vascular surgery

OBJECTIVE

To determine the value of dobutamine-atropine stress echocardiography and clinical variables to predict perioperative and late cardiac events in patients scheduled for elective major non-cardiac vascular surgery.

DESIGN

Blinded prospective study.

PATIENTS

Patients (n = 187 mean age 69 yrs).

MEASUREMENTS

Dobutamine-atropine stress test was performed preoperatively. Results were not used for clinical management. The clinical risk profile was evaluated by Detsky's score.

RESULTS

Technically adequate images were obtained in 185/187 patients, one major complication occurred (ventricular fibrillation) and four tests were prematurely stopped due to side effects. Data from 181 patients were analysed. The stress test was positive (new or worsened wall motion abnormality) in 56/181 patients. Perioperative cardiac events were: five fatal myocardial infarctions, three non-fatal myocardial infarctions, nine unstable angina pectoris and one pulmonary edema. All patients with a cardiac event had a positive stress test (18/56). No event occurred in patients with a negative stress test. By multivariate analysis only a new wall motion abnormality during the stress test (odds ratio 45.0, 6-369) was a significant predictor of cardiac events. Patients (n = 154) were followed after operation for 16 +/- 9 months. Twenty-four cardiac events occurred in 21 patients: six fatal myocardial infarctions, three non-fatal myocardial infarctions, six unstable angina pectoris, three ventricular arrhythmias and six congestive heart failures. The stress echo was positive in 19/21 patients with late cardiac events. The cardiac events correlated by multivariate analysis with a history of myocardial infarction (odds ratio 9.6, 1.9-47.7) and new wall motion abnormalities (odds ratio 6.2, 1.5-25.1).

CONCLUSION

Dobutamine-atropine stress echocardiography is a relatively safe and useful test to identify patients at risk of perioperative and late postoperative cardiac events.

Safety of dobutamine-atropine stress echocardiography in patients with suspected or proven coronary artery disease

The purpose of this study was to establish the safety of high-dose dobutamine-atropine stress echocardiography in patients with suspected or proven coronary artery disease. Six hundred fifty consecutive examinations were completed. Mean age of patients was 61 years; 300 had a previous myocardial infarction. Heart rate increased from 73 to 129 beats/min during stress testing, blood pressure did not change significantly (from 140/81 to 150/80 mm Hg). Atropine was added to dobutamine in 239 patients when no ischemia was induced with dobutamine alone and the peak heart rate was < 85% of the theoretical maximal heart rate. Atropine was more frequently administered to patients taking beta blockers (77 vs 27%, p < 0.001). New wall motion abnormalities developed in 243 patients (37%). Significant or symptomatic cardiac tachyarrhythmias, or both, developed during 24 examinations: 1 patient developed ventricular fibrillation, 3 patients developed sustained ventricular tachycardia, 12 patients experienced nonsustained ventricular tachycardia (< 10 beats) and 8 patients had paroxysmal atrial fibrillation. Cardiac arrhythmias were more frequent in patients with a history of ventricular arrhythmias (ventricular tachycardia and fibrillation) (odds ratio 9.9, 2.0 to 45) or left ventricular dysfunction at rest (wall motion score > 1.12) (odds ratio 2.9, 1.1-7.6), but not associated with atropine addition. No death or myocardial infarction occurred. The full dose was not given to 13 patients despite absence of signs or markers of ischemia for limiting side effect, yielding an overall feasibility of the stress test of 98%.(ABSTRACT TRUNCATED AT 250 WORDS)

Atropine increases the accuracy of dobutamine stress echocardiography in patients taking beta-blockers

Dobutamine-atropine stress echocardiography is used for the non-invasive diagnosis of coronary artery disease, but stress test results may be influenced by beta-blockers. The aim of this study was to assess if the addition of atropine can compensate for the presence of beta-blockers in dobutamine stress echocardiography. Twenty-six patients referred for evaluation of chest pain were studied twice, on and off metoprolol 100 mg b.i.d. (in random order sequence) with a wash-out period of at least 48 h. Dobutamine stress echocardiography was performed using up to 40 micrograms.kg-1.min-1, followed, if necessary, by the addition of atropine to achieve 85% of the age-predicted maximal heart rate, unless symptoms or markers of ischaemia appeared. Atropine was given to patients on beta-blockers more often [(22/26) vs (6/26)] than to those off beta-blockers (P < 0.001). Heart rate at every stage of the test was lower on beta-blockers. Chest pain occurred in patients on beta-blockers significantly less than in those off beta-blockers (8% vs 46%), and the addition of atropine made no significant difference (31% vs 46%). During dobutamine stress, new wall motion abnormalities occurred in three patients on beta-blockers (12%); this number increased to 15 after the addition of atropine (57%). New or worsened wall motion abnormalities occurred in 12 patients (46%) off beta-blockers with dobutamine alone and in 14 patients after adding atropine (53%).(ABSTRACT TRUNCATED AT 250 WORDS)

Dobutamine stress echocardiography for assessment of perioperative cardiac risk in patients undergoing major vascular surgery

BACKGROUND

The purpose of this study was to determine the predictive value of dobutamine stress echocardiography for perioperative cardiac events in patients scheduled for elective major noncardiac vascular surgery.

METHODS AND RESULTS

Patients (n = 136; mean age, 68 years) unable to exercise underwent a dobutamine stress test before surgery (incremental dobutamine infusion [10-40 micrograms.kg-1.min-1] continued with atropine [0.25-1 mg i.v.] if necessary to achieve 85% of the age-predicted maximal heart rate without symptoms or signs of ischemia). The clinical risk profile was evaluated by Detsky's modification of Goldman's risk factor analysis. Echocardiographic images were evaluated by two observers blinded to the clinical data of the patients, and results of the test were not used for clinical decision making. Technically adequate images were obtained in 134 of 136 patients, one major complication occurred (ventricular fibrillation), and three tests were discontinued prematurely because of side effects. Finally, data from 131 patients were analyzed with univariate and multivariate methods. The dobutamine stress test was positive (new or worsened wall motion abnormality) in 35 of 131 patients. In the postoperative period, five patients died of myocardial infarction, nine patients had unstable angina, and one patient developed pulmonary edema. All patients with cardiac complications (15 patients) had a positive dobutamine stress test. No cardiac events occurred in patients with negative tests. Five patients with a technically inadequate or prematurely stopped test were operated on without complications. By multivariate analysis (logistic regression), only age > 70 years and new wall motion abnormalities during the dobutamine test were significant predictors of perioperative cardiac events.

CONCLUSIONS

Dobutamine stress echocardiography is a feasible, safe, and useful method for identifying patients at high or low risk of perioperative cardiac events. The test yields additional information, beyond that provided by clinical variables, in patients who are scheduled for major noncardiac vascular surgery.

Isocaloric feeding and medium chain triglycerides fail to improve liver function tests in a patient with Crohn's disease and a high output stoma

A patient with Crohn's disease complicated by multiple fistulae to the skin and bladder and a high-output stoma following previous multiple short bowel resections developed liver dysfunction during total parenteral nutrition. Isocaloric feeding based on calorimetry and changing from a long chain triglyceride emulsion to a mixture of medium and long chain triglyceride emulsion failed to improve liver function. Surgical removal of the affected small bowel resulted in a rapid improvement of the liver function despite continuation of total parenteral nutrition.

Pyomyositis: an unusual complication of Staphylococcus aureus infection

Pyomyositis, an unusual complication of Staphylococcus aureus infection. Treatment consists of surgical drainage and antibiotics.

Pancreatitis induced by disodium azodisalicylate

A patient with Crohn's disease of the colon developed severe abdominal pain after salicylicazosulfapyridine and after disodium azodisalicylate therapy. Raised serum and urinary amylase levels were found after disodium azodisalicylate. Rechallenge with disodium azodisalicylate caused a recurrence of the pain and of the elevated amylase levels. The time course of these episodes was compatible with 5-aminosalicylate-induced pancreatitis.

Blood pressure response of nephrectomized subjects and patients with essential hypertension to ramipril: indirect evidence that inhibition of tissue angiotensin converting enzyme is important

The kinetics of blood pressure changes and plasma angiotensin converting enzyme (ACE) inhibition in response to ramipril (HOE 498), 10 mg orally, were studied in 6 nephrectomized subjects 12 hours after ultrafiltration and in 10 patients with essential hypertension. Ramipril lowered supine and standing blood pressure in both groups, but the effect was greater in essential hypertension. The maximal blood pressure response followed the effect on plasma ACE after a lag time of 3 to 4 hours in both groups. These data provide indirect evidence that ramipril lowers blood pressure, at least in part, independently of its effect on the circulating renin-angiotensin system, possibly by acting on tissue ACE.

Familial cortisol resistance: differential diagnostic and therapeutic aspects

A 26-yr-old woman presented with hirsutism, male pattern scalp baldness ("geheimratsecken"), and menstrual irregularities. She had no hypertension or other signs and symptoms of Cushing's syndrome. Plasma cortisol levels were greatly elevated and did not suppress normally in response to dexamethasone. Cortisol binding to transcortin was normal. Plasma androstenedione and testosterone levels were also increased, but 17-hydroxyprogesterone and aldosterone levels were normal. Further studies revealed an increased cortisol production rate, increased 24-h urinary cortisol excretion, increased plasma ACTH levels, a normal diurnal rhythm of cortisol at an elevated level, and normal increments of plasma ACTH, cortisol, GH, and PRL in response to insulin-induced hypoglycemia. The father and two brothers also had increased plasma cortisol levels, which did not suppress normally in response to dexamethasone. Chronic therapy with dexamethasone (at first 1 and later 0.5 mg, three times daily) for more than 30 weeks resulted in decreased hirsutism, normalization of scalp hair and menstrual cyclicity, and normal plasma testosterone and androstenedione levels. No signs or symptoms of Cushing's syndrome developed, and the central regulation of secretion of ACTH, cortisol, GH, and PRL (insulin test, diurnal rhythm) remained qualitatively normal at a lower set-point. We conclude that this patient had autosomal dominantly inherited hereditary (partial) cortisol insensitivity, which had resulted in increased adrenocortical cortisol and androgen secretion. The latter had not resulted in clinical symptoms in the three afflicted male members of the family, but had in the propositus. The results also indicate the potential usefulness of the insulin test in distinguishing this disorder from Cushing's disease.