Lack of association of exercise testing with coronary stent closure.

This report is a summary of the experience at a tertiary medical care facility with patients who had undergone exercise testing soon after placement of coronary arterial stents. In 261 patients, no acute coronary events occurred that could be attributed to the exercise tests.

Weekend and holiday exercise testing in patients with chest pain.

OBJECTIVE: To determine the outcome, safety, and possible cost savings of patients undergoing weekend or holiday exercise treadmill testing. DESIGN: Medical records of all 195 patients scheduled for weekend and holiday exercise testing were reviewed, and 77.9% of patients were contacted by telephone to ascertain medical outcomes and need for further emergency department or inpatient care. Costs were calculated from estimates of days of hospitalization saved and incremental costs incurred in conjunction with weekend or holiday testing. SETTING: Urban tertiary care academic medical center. PATIENTS: A total of 195 patients were scheduled for testing, and 181 tests were performed. Over three quarters (75.1%) of patients underwent testing for assessment of chest pain. Other indications included risk stratification after myocardial infarction or coronary angioplasty or prior to noncardiac surgery, or evaluation for arrhythmias, dyspnea, or syncope. MEASUREMENTS AND MAIN RESULTS: Outcomes included results and complications of testing, hospital course after testing, subsequent emergency department visits and readmissions, myocardial infarction, need for cardiac catheterization or revascularization, and mortality. No complications were noted during testing. In 136 patients tested for the indication of chest pain, 90 (66.2%) had negative tests, 39 (28. 7%) were intermediate, and 6 (4.4%) were positive for ischemia. Same day discharge occurred in 115 (84.6%) of the patients, saving an estimated 185 days of hospitalization ($316.83 per patient tested). Event rates over the 6 months following discharge were low. CONCLUSIONS: Weekend and holiday exercise testing is a safe and effective means of risk stratification prior to hospital discharge for patients with chest pain. It also reduces length of stay and is cost saving.

Captopril reduces the VE/VCO2 ratio in myocardial infarction patients with low ejection fraction.

STUDY OBJECTIVES: To determine whether captopril (CAP) therapy had an effect on the minute ventilation/carbon dioxide output (VE/VCO2) ratio at submaximal levels of exercise in asymptomatic patients with reduced left ventricular function after myocardial infarction. DESIGN: Double blinded, randomized, prospective, repeated measures. PATIENTS AND INTERVENTIONS: One hundred thirty-five patients with left ventricular ejection fractions of < 40% were randomly assigned to a treatment group (CAP; n = 62) or a placebo group (PLC; n = 73). Subjects had cycle ergometer exercise tests at 2 to 6 months (T1), 10 to 14 months (T2), and > 22 months (T3) postmyocardial infarction. MEASUREMENTS: Oxygen uptake (VO2), VCO2, and VE were measured throughout each exercise test. Dependent variables were peak VO2 (VO2peak), the ventilatory anaerobic threshold (VAT), and the VE/VCO2 ratio measured at 30 W and at 75% VO2peak. RESULTS: VO2peak and VAT did not differ as a result of treatment (CAP vs PLC; p = 0.92 and 0.80) or over time (T1 vs T2 vs T3; p = 0.51 and 0.07). VE/VCO2 was significantly lower for CAP at 30 W (p = 0.05) and, although lower at 75% VO2peak, did not obtain statistical significance (p = 0.22). The between group differences were larger at T2 and T3 when compared with T1. CONCLUSIONS: CAP resulted in a reduced VE/VCO2 ratio during submaximal exercise. The reduced ventilation may permit patients to perform their normal activities of daily living at a lower perception of difficulty, reduce symptoms, and provide an improved quality of life.

Cardiorespiratory symptoms in response to physiological arousal.

OBJECTIVE: To develop a laboratory paradigm for assessing the tendency to amplify somatic symptoms and report bodily distress. METHOD: Reports of four different cardiopulmonary symptoms were obtained during standardized, treadmill exercise, while the physiological parameters which induce these symptoms were simultaneously measured. Two indices were developed to compare symptom reporting across patients: symptom severity after reaching 80% of predicted, maximal exercise capacity; and the magnitude of physiological arousal necessary to induce an initial sensation of discomfort. RESULTS: Fifty-one medical outpatients with a chief complaint of palpitations were studied. Symptom distress at 80% of maximal exercise capacity was significantly associated with state anxiety and daily life stress. The complaint of "heart racing" first occurred at a significantly lower heart rate for patients who were older, more anxious, and reported more daily life stress. Measures of hypochondriasis, somatization, bodily amplification, and bodily absorption were not significantly associated with either symptom measure. CONCLUSIONS: Standardized exercise testing may provide a suitable paradigm with which to study the tendency to amplify symptoms and to somatize. The distress reported by different subjects at 80% of maximal exercise capacity may be considered an index of the discomfort engendered by a standardized stimulus, whereas the point of onset of discomfort may be a measure of the patient's threshold for becoming symptomatic. These findings are not conclusive, but do suggest that patients who are more anxious and under more stress tend to report more intense cardiopulmonary symptoms at comparable levels of physiological arousal, and to have a lower threshold for experiencing discomfort.

Recipient-to-donor atrioatrial conduction after orthotopic heart transplantation: surface electrocardiographic features and estimated prevalence.

Recipient-to-donor atrioatrial conduction across a suture line has been rarely reported after orthotopic heart transplantation. The relation of such conduction to symptomatic arrhythmias and its prevalence are not known. Recipient-to-donor atrioatrial conduction was demonstrated in a 28-year-old woman with paroxysmal supraventricular tachycardia 7 years after orthotopic heart transplantation. Atrial tachycardia in the recipient atria conducted 2:1 to the donor atria and was eliminated by radiofrequency catheter ablation of a left-sided atrioatrial electrical connection. The electrocardiogram at rest and during exercise, recorded before ablation of the recipient-to-donor connection, showed frequent atrial premature complexes, with variable coupling to the preceding sinus beats, and a change in P-wave morphology during exercise, which reverted to normal during the recovery period. These findings were eliminated by ablation of the recipient-to-donor connection. To determine the prevalence of recipient-to-donor atrioatrial conduction late after transplantation, we evaluated the exercise electrocardiograms of 50 subjects > 5 years after heart transplantation for these features of recipient-to-donor conduction. At least 1 feature was present in 5 subjects, and both were present in 1 subject. Electrical conduction can occur across surgical suture lines in the atria. Recipient-to-donor atrioatrial conduction may occur in < or = 10% of patients late after heart transplantation. It is a potential cause of arrhythmias that can be effectively treated with radiofrequency catheter ablation.

Clinical correlates and prognostic significance of early negative exercise tolerance test in patients with acute chest pain seen in the hospital emergency department.

An exercise tolerance test (ETT) is often performed to identify patients for early discharge after observation for acute chest pain, but the safety of this strategy is unproven. We prospectively studied 276 low-risk patients who underwent an ETT within 48 hours after presentation to the emergency department with acute chest pain. The ETT was considered negative if subjects achieved at least stage I of the Bruce protocol and the electrocardiogram showed no evidence of ischemia. There were no complications associated with ETT performance. The ETT was negative in 195 patients (71%); there was no identifiable subsets of patients at very low probability of an abnormal test. During the 6-month follow-up, patients with a negative ETT had fewer additional visits to the emergency department (17% vs 21%, respectively; p < 0.05) and fewer readmissions to the hospital (12% vs 17%; p < 0.01) than those with positive or inconclusive ETTs. No patient with a negative ETT died and only 4 patients with a negative ETT experienced a major cardiac event (myocardial infarction, coronary angioplasty, or bypass) within 6 months. Among these 4 patients, only 1 had an event within 4 months. In conclusion, our results suggest that ETT can be safely used to identify patients at low risk of subsequent events. Patients without a clearly negative test are at increased risk for readmission and cardiac events, and should be reevaluated either during the same admission or shortly after discharge.

A critical pathway for management of patients with acute chest pain who are at low risk for myocardial ischemia: recommendations and potential impact.

BACKGROUND: Use of resources for patients with acute chest pain may be improved with clinical strategies that integrate research, Bayesian analysis, and expert opinion. OBJECTIVES: To 1) develop a critical pathway for management of patients with acute chest pain who are at low risk for complications of ischemic heart disease and 2) assess the potential effects of implementation of the pathway on patient safety and resource use. DESIGN: Evidence-based consensus and prospective cohort study. SETTING: Urban teaching hospital. PATIENTS: Patients at least 30 years of age who were seen in the emergency department for chest pain and who did not have a history of trauma or abnormalities on radiologic study. INTERVENTION: Physician-opinion leaders defined criteria for patient inclusion in the pathway and for remaining on the pathway after 6 or 12 hours of observation. Criteria were defined for appropriateness of direct admission, direct discharge, or 6 hours of observation followed by exercise treadmill testing. MEASUREMENTS: Number of patients admitted to the hospital, number of days that patients were hospitalized, and clinical outcome. RESULTS: 2898 of 4585 patients (63%) were admitted to the hospital; of the 2898, 1152 (40%) were classified as potentially eligible for the pathway and 1068 (93%) had a benign clinical course during the initial observation period. The 1068 patients had a mean length of stay of 2.8 +/- 4.8 days. If 47% of these patients had been discharged after observation and exercise testing, implementation of the pathway would have reduced the number of admissions by 505 (17%) and days of hospitalization by 1407 (11%). CONCLUSIONS: Retrospective analysis suggests that a critical pathway for patients with acute chest pain may substantially reduce resource use. Prospective study is needed to ensure increased efficiency without increased adverse outcomes.

Long-term sequential changes in exercise capacity and chronotropic responsiveness after cardiac transplantation.

BACKGROUND: Peak exercise capacity improves early after orthotopic cardiac transplantation. However, the physiological response to exercise remains abnormal, with a reduced rate of heart rate (HR) rise and reductions in peak exercise HR and the increment in HR from rest to peak exercise. This chronotropic incompetence is due in large part to cardiac denervation. If reinnervation occurs after transplantation, it might result in an improvement in both chronotropic responsiveness and maximal exercise capacity. We therefore hypothesized that the chronotropic response to exercise and maximal exercise capacity would improve with time after transplantation. METHODS AND RESULTS: Peak symptom-limited cardiopulmonary exercise tests performed in 57 clinically stable cardiac transplant recipients (mean age, 45 +/- 2 years) serially for up to 5 years after transplantation and in 33 control subjects without heart disease were analyzed retrospectively. Pretransplantation exercise tests were also performed in 41 patients an average of 4.7 +/- 0.6 months before transplantation. At 1 year after transplantation, peak oxygen consumption was 16.6 +/- 0.9 mL.kg-1.min-1, reflecting a 43% increase versus pretransplantation. Nevertheless, compared with control subjects, maximal exercise capacity and the HR response to exercise were subnormal in transplant recipients. There were no further increases in peak exercise capacity, peak exercise HR, or the peak increment in HR with exercise up to 5 years after transplantation. CONCLUSIONS: One year after cardiac transplantation, peak exercise capacity and chronotropic responsiveness are subnormal. There is no further improvement in peak exercise capacity or chronotropic responsiveness as late as 5 years after transplantation. These data indicate that with regard to chronotropic responsiveness, functionally significant cardiac reinnervation does not occur between the first and fifth years after transplantation.

Last-minute preoperative cardiology consultations: epidemiology and impact.

To identify clinical predictors of last-minute preoperative cardiology consultations and to evaluate the impact of these consultations on patient care, we performed a retrospective case-control study including all 166 patients who received unscheduled cardiology consultations at the preadmission testing center (PATC) of an urban teaching hospital. Control subjects were 166 patients matched by date and category of surgical procedure. Significant (p < 0.05) independent predictors of last-minute consultations included history of myocardial infarction (odds ratio [OR] = 23.7; 95% confidence interval [CI] = 1.5 to 373), history of chest pain (OR = 15.3; 95% CI = 3.7 to 62.9), history of chronic obstructive lung disease (OR = 5.9; 95% CI = 1.1 to 32.9), prior echocardiography (OR = 3.4; 95% CI = 1.2 to 9.8), and age (OR per decade = 1.1; 95% CI = 1.04 to 1.1). Thus among patients undergoing elective noncardiac surgery, last-minute preoperative consultations are common and are usually precipitated by an abnormal electrocardiogram or history of cardiovascular disease. Last-minute consultations may be preventable if those patients with risk factors for consultation are identified in advance of the preadmission evaluation and referred for elective consultation.

Physical working capacity after acute myocardial infarction in patients with low ejection fraction and effect of captopril.

Previous studies after acute myocardial infarction (AMI) have reported conflicting results on the effects of angiotensin-converting enzyme inhibition on physical working capacity. In an effort to provide more insight into this subject, we examined the effects of captopril on working capacity of patients who had low ejection fractions but no congestive heart failure after AMI. One hundred sixty-six participants were recruited from 5 centers after randomization to either captopril or placebo for the Survival and Ventricular Enlargement study. Upright cycle ergometer tests were performed with continuous measurements of respiratory gases at 4, 12, and 24 months after AMI. Our study concurs with 2 of 3 previous post-AMI studies and supports the conclusion that working capacity is not affected by angiotensin-converting enzyme inhibition at 4 or 12 months after AMI in patients without congestive heart failure. In addition, no significant effect of captopril was noted at 24 months after AMI. Peak oxygen uptake tended to decrease between 12 and 24 months in the placebo group by an average (+/- SD) of -22 +/- 322 ml/min (n = 66), but to increase in the captopril group (+62 +/- 289, n = 57), a difference that was significant (Mann-Whitney chi-square, p = 0.02). This post-hoc observation suggests that a late beneficial effect may have been masked by inadequate study duration. Known benefits of captopril appear not to include an increase in working capacity within the first 24 months after AMI.

Cholesterol and Recurrent Events: a secondary prevention trial for normolipidemic patients. CARE Investigators.

Although elevated plasma cholesterol levels represent a well-established and significant risk for developing atherosclerosis, there is a wide spectrum of cholesterol levels in patients with coronary artery disease (CAD). Most secondary prevention studies have generated convincing evidence that cholesterol reduction in patients with high cholesterol levels is associated with improved clinical outcome by reducing risk of further cardiovascular events. However, other risk factors may play a prominent role in the pathogenesis of coronary disease in the majority of patients with near-normal cholesterol values. The Cholesterol and Recurrent Events (CARE) study was designed to address whether the pharmacologic reduction of cholesterol levels with the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, pravastatin, would reduce the sum of fatal coronary artery disease (CAD) and nonfatal myocardial infarction (MI) in patients who have survived an MI yet have a total cholesterol value < 240 mg/dl (< 6.2 mmol/liter). The other inclusion criteria for this study were age 21-75 years, low density lipoprotein (LDL) cholesterol levels of 115-174 mg/dl (3.0-4.5 mmol/liter), and fasting serum triglyceride levels < 350 mg/dl (< 4.0 mmol/liter). A total of 4,159 eligible consenting patients without other study exclusions were then randomly assigned to receive either pravastatin 40 mg daily or matching placebo in addition to their individualized conventional therapy. The trial was designed to have a median follow-up of 5 years. Study endpoints will be evaluated with respect to predefined subgroups according to baseline lipid values, age, gender, prior cardiovascular risk factors, and history.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise for the cardiac patient. Long-term maintenance phase.

Exercise is an important part of the long-term management of patients with heart disease. Patients should be screened carefully and receive an exercise prescription that is safe and effective based on their exercise test results. For the safest programs, individuals should either restrict their activity to moderate intensities or exercise in the presence of medical supervision. The results of such programs have been shown to improve both the quality and quantity of life.

Lack of heart rate variation between morning and afternoon exercise testing in coronary artery disease patients.

The purpose of this study was to investigate cardiovascular [heart rate (HR), blood pressures, rate-pressure product (RPP)], physiological (oxygen uptake), and metabolic (blood plasma lactic acid concentration) responses during symptom-limited graded exercise testing (SL-GXT) during early morning and late afternoon hours in an unmedicated, regularly exercising, coronary artery disease population. Subjects, males ages 41-71 yr (n = 11), underwent SL-GXT via cycle ergometry at 8:30 A.M. and 4:30 P.M. HR, systolic blood pressure, diastolic blood pressure, and RPP were evaluated at rest and at submaximal and peak work. Oxygen uptake and rate of perceived exertion were also determined at submaximal and peak power output, with blood plasma lactic acid concentration measured at peak work. Data, analyzed by the paired t test, failed to demonstrate any significant variation in HR, systolic blood pressure, diastolic blood pressure, RPP, or blood plasma lactic acid responses during exercise at the two points used. Oxygen uptake did not significantly change at any submaximal intensity. Thus SL-GXT results obtained at early morning (8:30 A.M.) and late afternoon (4:30 P.M.) are a reproducible, reliable means of prescribing exercise HR and work intensities.

Prognostic significance of the Karnofsky Performance Status score in patients with acute myocardial infarction: comparison with the left ventricular ejection fraction and the exercise treadmill test performance. The MILIS Study Group.

The prognostic significance of functional status has not been previously studied in the setting of acute myocardial infarction. We assessed the Karnofsky Performance Status (KPS) score, a simple functional status scale that is commonly used to categorize physical ability, in 849 patients with acute myocardial infarction who were enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS) study. We then compared the KPS score with other predictors of prognosis in these patients. In patients who presented with acute myocardial infarction, a lower KPS score (less than 8 on a scale of 1 to 10) 3 weeks before the index infarction was associated with a higher incidence of congestive heart failure, in-hospital cardiac arrest, and mortality during hospitalization, as compared with patients with KPS scores greater than or equal to 8 (each p less than 0.001). Cumulative 1-year and 4-year mortality rates were significantly higher in patients with KPS scores less than 8, as compared with patients with KPS scores greater than or equal to 8 (42.5% vs. 12.6% at 1 year and 61.6% vs 25.1% at 4 years, respectively; both p less than 0.001). The left ventricular ejection fraction on admission was significantly lower in patients with KPS scores less than 8, as compared with those with KPS scores greater than or equal to 8 (p less than 0.019). The cumulative mortality rate was equally well predicted by low KPS score and by left ventricular ejection fraction (both p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Hospital supervised vs home exercise in cardiac rehabilitation: effects on aerobic fitness, anxiety, and depression.

This study focused on the effects of hospital supervision and type of prescribed home exercise in cardiac rehabilitation programs on aerobic fitness, anxiety, and depression. Men who had a myocardial infarction were randomly assigned to four exercise programs: The first program consisted of purely hospital-based exercise. The second and third programs combined hospital and home exercise, including either bicycling or walking at home. In the fourth program, patients were encouraged to exercise at home, but were given no specific guidance. Fifty-two patients finished the eight-week exercise program and 35 completed the psychologic questionnaires. At the end of the eight weeks, there were significant differences in the programs' effects on aerobic fitness. Purely hospital-supervised exercise and the combination of hospital-supervised bicycling with home walking increased aerobic fitness more than completely unsupervised exercise. Furthermore, there were differences in the programs' effects on manifest anxiety. The combination of home and hospital bicycling was less beneficial than home walking and hospital bicycling or even completely unsupervised exercise at home. The results indicate that the degree of hospital supervision and the type of prescribed home exercise are important design features which may affect the success of cardiac rehabilitation exercise programs. No effects of the different exercise programs on patients' depression could be found. In general, a close relationship between aerobic fitness and anxiety or depression could not be demonstrated. Implications of these findings for the design of cardiac rehabilitation exercise programs are discussed.

Efficacy and safety of perhexiline maleate in refractory angina. A double-blind placebo-controlled clinical trial of a novel antianginal agent.

Despite large gains in the medical and surgical treatment of angina pectoris in the past two decades, many patients are refractory to conventional medical therapy and are unsuitable for a first or, more commonly, repeat coronary revascularization procedure. We evaluated the efficacy of perhexiline maleate, a drug with an antianginal mechanism of action in humans that is as yet unknown, by using a randomized double-blind placebo-controlled crossover design in 17 patients with refractory angina who continued to receive maximal antianginal therapy, typically including nitrates, a beta-blocker, and a calcium channel antagonist. In view of perhexiline's potential for hepatic and neurological toxicity, plasma drug levels were monitored and maintained in the 150-600 ng/ml range. Sixty-three percent of patients were judged perhexiline responders by objective exercise testing criteria, as compared with 18% of patients on placebo (p less than 0.05). By blinded review of subjective measures of anginal frequency and severity, 65% of patients noted an improvement while on perhexiline, whereas no patient identified the placebo phase with improvement. Side effects observed in 29% of patients were minor and related to transient elevations of blood levels of more than 600 ng/ml; no patient suffered hemodynamic or cardiac conduction abnormalities attributable to perhexiline. With attention to the pharmacokinetics of perhexiline's elimination in individual patients, this novel antianginal agent seems to be safe and effective and deserves further evaluation in patients already receiving maximal antianginal therapy who are not candidates for revascularization procedures.

Acute increase in exercise capacity with milrinone: lack of correlation with resting hemodynamic responses.

1. The acute administration of milrinone, a positive inotropic vasodilator agent, improves resting hemodynamic function and maximal and submaximal metabolic responses to exercise in patients with severe congestive heart failure. 2. To determine whether the improvement in exercise capacity induced by milrinone administration can be predicted by its acute positive inotropic and/or vasodilator effects at rest, milrinone was administered intravenously (progressive doses of 12.5 to 75 microns/kg) to 15 patients with heart failure (functional classes III and IV, New York Heart Association) at rest, and during maximal upright exercise testing on a cycle ergometer. Serum drug levels were matched for the resting and exercise tests. Drug administration for exercise tests was placebo-controlled and double-blind. 3. At rest, milrinone administration caused substantial decreases in right atrial pressure (-53%), left ventricular end-diastolic pressure (-30%), and systemic vascular resistance (-35%); and increases in cardiac index (+59%), peak positive dP/dt (+20%) and stroke work index (+51%). Administration of milrinone during exercise resulted in a 15% increase in peak oxygen uptake and a 16% increase in anaerobic threshold. However, none of the changes in resting hemodynamic function correlated significantly in magnitude with the changes in peak oxygen uptake and anaerobic threshold. 4. Thus, the acute improvement in exercise capacity that occurs with milrinone is not predicted by the positive inotropic or vasodilator effects of the drug at rest.

Acute increase in exercise capacity with milrinone: lack of correlation with resting hemodynamic responses

1-The acute administration of milrinone, a positive inotropic vasodilator agent, improves resting hemodynamic function and maximal and submaximal metabolic rsponses to exercice in patients with severe congestive heart failure. 2. to determine whether the improvement in exerecise capacity induced by milrinone administration can be predicted by its acute positive inotropic and/or vasodilator effects at rest, milrinone was adminstered intravenously (progressive doses of 1.5 to 75 microng/Kg) to 15 patients with heart failure (functional classes III and IV, New York Heart Association) at rest, and during maximal upright exercise testing on a cycke ergometer. Serum drug levels were matched for the resting and exercise tests. Drug administration for exercise tests was placebo-controlled and double-blind. 3. At rest, milrinone administration caused substantial decreases in right atrial pressure (-53%), left ventricular end-diastolic pressure (-30%), and systemic vascular resistance (-35%); and increases in cardiac index (+59%), peak positive dP/dt (+20%) and stroke work index (+51%). Administration of milrinone during exercise resulted in a 15% increase in peak oxygen uptake and a 16% increase in anaerobic threshold. However, none of the changes in resting hemodynamic function correlated significantly in magnitude with the changes in peak oxygen uptake and anaerobic threshold. 4. Thus, the acute improvement in exercise capacity that occus with milrinone is not predicted by the positive inotropic or vasodilator effects of the drug at rest