Cardiac parasympathetic activity in severe uncomplicated coronary artery disease.

BACKGROUND--Previous studies have suggested that coronary artery disease is independently associated with reduced cardiac parasympathetic activity, and that this is important in its pathophysiology. These studies included many patients with complications that might be responsible for the reported autonomic abnormalities. OBJECTIVE--To measure cardiac parasympathetic activity in patients with uncomplicated coronary artery disease. PATIENTS AND METHODS--44 patients of mean (SD) age 56 (8) with severe uncomplicated coronary artery disease (symptoms uncontrolled on maximal medical treatment; > 70% coronary stenosis at angiography; normal ejection fraction; no evidence of previous infarction, diabetes, or hypertension). Heart rate variability was measured from 24 hour ambulatory electrocardiograms by counting the number of times successive RR intervals exceeded the preceding RR interval by > 50 ms, a previously validated sensitive and specific index of cardiac parasympathetic activity. RESULTS--Mean (range) of counts were: waking 112 (range 6-501)/h, sleeping 198 (0-812)/h, and total 3912 (151-14 454)/24 h. These mean results were unremarkable, and < 10% of patients fell below the lower 95% confidence interval for waking, sleeping, or total 24 hour counts in normal people. There was no relation between the severity of coronary artery disease or the use of concurrent antianginal drug treatment and cardiac parasympathetic activity. CONCLUSION--In contrast with previous reports no evidence of a specific independent association between coronary artery disease and reduced cardiac parasympathetic activity was found. The results of previous studies may reflect the inclusion of patients with complications and not the direct effect of coronary artery disease itself.     

Exercise habits and physical performance during comprehensive rehabilitation after coronary artery bypass surgery.

The effects of training as part of a comprehensive rehabilitation programme on exercise capacity and habits was studied in 171 male coronary artery bypass surgery patients randomized into a rehabilitation (R) (n = 93) and a reference, hospital-based treatment (H), group (n = 78). The rehabilitation programme started with a 2-day informative course before surgery and continued with a 3-week exercise-based course 2 months after surgery followed by a 2-day refresher 8 months post-operatively. The percentages of subjects having regular exercise were 22% and 10% pre-operatively, 42% and 38% 6 months and 46% and 38% 12 months after surgery in the R and H groups, respectively. The changes in the proportions observed in R and H groups were not significantly different. Total work during a bicycle exercise test increased from 38.9 +/- 24.3 kJ pre-operatively to 64.0 +/- 31.4 kJ 6 months (P less than 0.001) and to 70.0 +/- 35.7 kJ 12 months (P less than 0.001) post-operatively in group R and from 40.8 +/- 25.6 kJ to 57.3 +/- 26.6 kJ (P less than 0.001) and to 60.4 +/- 30.8 kJ (P less than 0.001) in group H, respectively. The increase from the pre-operative value was greater in group R than in group H both 6 (P = 0.03) and 12 months (P = 0.02) after surgery. Respective changes occurred in maximal work load, but the increase was significantly greater in group R than in group H only 12 months post-operatively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exercise two-dimensional echocardiography for diagnosis of coronary artery disease

To improve ultrasound images during exercise 2-dimensional echocardiography (2-D echo), a device was developed to hold the transducer and maintain its orientation relative to the heart. The value of this technique in detecting wall motion abnormalities and changes in ejection fraction was evaluated in 54 men undergoing stress test for angina. Thallium-201 scanning, electrocardiography and exercise 2-D echo were recorded concurrently. Technically satisfactory echo studies were obtained in 47 patients (87%). The sensitivity and specificity of exercise echo in the detection of myocardial ischemia as judged by wall motion abnormalities were 100% and 93%, respectively. Sixteen patients with normal thallium scans increased their ejection fraction (EF) estimated by echo (from 52 +/- 1% at rest to 67 +/- 1% at maximal exercise, p less than 0.001); all showed an increase of 5% or more. In contrast, 11 patients who had reversible thallium scan defects showed a consistent decrease in EF (from 53 +/- 2% at rest to 43 +/- 2% during exercise, p less than 0.001); 20 patients with irreversible thallium scan defects showed no specific trend in the EF (48 +/- 2% at rest and 50 +/- 2% during exercise, difference not significant). Changes in heart rate and blood pressure did not distinguish the 3 groups of patients. Our technique of exercise 2-D echo may be useful for detecting wall motion abnormalities and EF changes during exercise and possibly enhance the sensitivity of thallium scanning in the noninvasive diagnosis of coronary artery disease.     

Determinants of hospital mortality after coronary artery bypass grafting.

OBJECTIVES: To examine causes of death and to find predictors of hospital mortality after elective coronary artery bypass graft (CABG) surgery. DESIGN: Case-control study. SETTING: Tertiary teaching hospital. METHODS: We prospectively collected various preoperative, operative, and immediate postoperative variables in a cohort of patients undergoing elective CABG surgery. RESULTS: Of the 2,014 consecutive patients (mean [+/- SD] age of 61.3+/-6.7 years old) undergoing elective CABG over a 2-year period, 27 patients (1.3%) died during their hospitalization. The main causes of death (either isolated or in combination) were cardiogenic shock (n = 13), brain death or stroke (n = 7), septic shock (n = 4), ARDS (n = 2), and pulmonary embolism (n = 1). A univariate statistical analysis revealed factors that significantly correlate with outcome: patient age, preoperative left ventricular ejection fraction, bypass time, aortic cross-clamp time, number of blood units transfused, number of inotropic agents administered in the operating room during the first postoperative day (POD), history of arterial hypertension, intra-aortic balloon pump usage, and perioperative development of shock. A logistic regression analysis showed that the combination of the number of inotropes and the number of blood units administered in the operating room during POD 1 was the most important determinant of outcome, with an overall positive predictive value of 91.7%. CONCLUSIONS: We conclude that the analysis of simple variables enhances our ability to accurately predict hospital mortality in patients undergoing elective CABG surgery. The number of inotropic agents and blood transfusions administered during the immediate postoperative period is the most important independent predictor of hospital mortality.     

Exercise ultrafast computed tomography for the detection of coronary artery disease

Ultrafast computed tomography permits the assessment of global and regional left ventricular function during exercise. To evaluate the feasibility of using this new technique for the diagnosis of coronary artery disease, 27 patients undergoing cardiac catheterization for diagnosis of chest pain were evaluated. Fifteen patients had significant (greater than 50%) coronary artery stenosis by quantitative coronary angiography. One vessel disease was found in 12 patients and multivessel disease in 3. Fourteen (93%) of the 15 patients with significant coronary stenosis had a decrease in ultrafast computed tomographic ejection fraction during exercise from (mean +/- SD) 65 +/- 7% to 60 +/- 7% (p less than 0.001). The tomographic ejection fraction increased greater than 5% units during exercise in 10 (83%) of the 12 patients with normal coronary arteries. The mean tomographic ejection fraction in this group was 68 +/- 6% at rest and 75 +/- 6% at peak exercise (p less than 0.001). Regional wall motion was quantified by analyzing the segmental ejection fraction of 12 30 degree pie segments at each tomographic level of the left ventricle. A new regional wall motion abnormality developed during exercise in 12 (86%) of 14 patients with coronary artery disease; one patient was excluded because of a technical problem in data storage. Eleven (93%) of the 12 patients with normal coronary arteries had normal wall motion during exercise. In no patient with ischemic heart disease were both variables, ejection fraction response and regional wall motion, normal. Exercise ultrafast computed tomography appears to be a useful technique for the evaluation of coronary artery disease in patients with chest pain and predominant single vessel coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exercise in the primary prevention of coronary artery disease

Since the 1950s there has been a steady accumulation of data from observational studies and clinical trials identifying a lack of physical activity, either in the industrial or leisure setting, as an independent major risk factor for coronary artery disease, with a similar relative risk as smoking, hypercholesterolemia and hypertension. More recently, poor cardiorespiratory fitness has also been shown to increase the risk of cardiovascular mortality significantly. Regular exercise is now known to have beneficial effects on peripheral and central circulation, skeletal muscle and myocardium, as well as lipid and carbohydrate metabolism. Individuals who become active in later life, for example, by way of a moderate intensity walking program, and who make only modest gains in fitness, nevertheless share in many of these health benefits and reduce their coronary artery disease risk. It is estimated that 60% of Canadians are physically inactive, a higher prevalence than for the other major risk factors. Consequently, efforts to encourage a more active lifestyle can have a significant impact on cardiovascular morbidity and mortality, with a marked reduction in costs to the health care system.     

Improved treatment of coronary heart disease by implementation of a Cardiac Hospitalization Atherosclerosis Management Program (CHAMP)

Despite scientific evidence that secondary prevention medical therapies reduce mortality in patients with established coronary artery disease, these therapies continue to be underutilized in patients receiving conventional care. To address this issue, a Cardiac Hospital Atherosclerosis Management Program (CHAMP) focused on initiation of aspirin, cholesterol-lowering medication (hydroxymethylglutaryl coenzyme A [HMG CoA] reductase inhibitor titrated to achieve low-density lipoprotein [LDL] cholesterol < or =100 mg/dl), beta blocker, and angiotensin-converting enzyme (ACE) inhibitor therapy in conjunction with diet and exercise counseling before hospital discharge in patients with established coronary artery disease. Treatment rates and clinical outcome were compared in patients discharged after myocardial infarction in the 2-year period before (1992 to 1993) and the 2-year period after (1994 to 1995) CHAMP was implemented. In the pre- and post-CHAMP patient groups, aspirin use at discharge improved from 68% to 92% (p <0.01), beta blocker use improved from 12% to 62% (p <0.01), ACE inhibitor use increased from 6% to 58% (p <0.01), and statin use increased from 6% to 86% (p <0.01). This increased use of treatment persisted during subsequent follow-up. There was also a significant increase in patients achieving a LDL cholesterol < or =100 mg/dl (6% vs 58%, p <0.001) and a reduction in recurrent myocardial infarction and 1-year mortality. Compared with conventional guidelines and care, CHAMP was associated with a significant increase in use of medications that have been previously demonstrated to reduce mortality; more patients achieved an LDL cholesterol < or =100 mg/dl, and there were improved clinical outcomes in patients after hospitalization for acute myocardial infarction.     

Cardiac fluoroscopy for the diagnosis of coronary artery disease: a meta analytic review

To evaluate variability in the reported accuracy of fluoroscopically detected coronary calcific deposits for predicting angiographic coronary disease, we applied meta analysis to 13 consecutively published reports comparing the results of cardiac fluoroscopy with coronary angiography. Population characteristics and technical and methodologic factors were analyzed. Sensitivity and specificity for predicting serious coronary disease compare quite well with those from the literature on the exercise ECG and the exercise thallium scintigram. Sensitivity increases and specificity decreases more significantly with patient age, and sensitivity is paradoxically lower in laboratories testing patients with more severe disease, as well as when 70% rather than 50% diameter narrowing is used to define angiographic disease. Work-up and test review bias were also significantly related to reported accuracy.     

Promotion of physical activity after hospitalization for COPD exacerbation: A randomized control trial

Background and Objective

Physical activity worsens during exacerbations of chronic obstructive pulmonary disease (COPD) and notably after hospitalizations. Pedometer-based interventions are useful to increase physical activity in stable patients with COPD. However, there is little information concerning the implementation of such programs following severe exacerbation. This study assessed the efficacy of a physical activity program after hospitalization for a COPD exacerbation.

Methods

We performed a prospective, 12-week, parallel group, assessor-blinded, randomized control trial in COPD patients hospitalized for an exacerbation. After discharge, physical activity and other secondary variables were assessed. Patients were allocated (1:1) to a physical activity promotion program (intervention group, IG) or usual care (control group, CG). Based on a motivational interview and accelerometer physical activity assessment, a patient-tailored, pedometer-based, progressive and target-driven program was designed. Linear mixed effect models were used to analyse between-group differences.

Results

Forty-six out of 61 patients recruited were randomized and 43 (IG = 20, CG = 23) completed the study. In-hospital and baseline characteristics were similar in both groups. After 12 weeks of intervention, the mean steps difference between groups was 2093 steps/day, p = 0.018, 95% CI 376–4012, favouring the IG. Only the IG significantly increased the number of steps/day compared to baseline (mean difference [95% CI] 2932 [1069–4795] steps; p = 0.004). There were no other between-group differences.

Conclusion

After hospitalization for a COPD exacerbation, a patient-tailored physical activity program based on a motivational interview and the use of pedometers, with progressive and customized targets, improved the number of steps/day.     

Determinants of health-related quality of life in patients with coronary artery disease.

BACKGROUND: Health-related quality of life (HRQL) is increasingly being assessed as an outcome parameter, especially in chronic diseases such as coronary artery disease (CAD), in which the goal of treatment is not only to prolong life but also to relieve symptoms and improve function. DESIGN: This study was carried out as a non-randomized prospective multicentre study. METHODS: Patients (N = 432) with CAD were assessed at baseline, 1 and 3 months after treatment assignment [medication, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)]. HRQL was assessed using the MacNew Heart Disease Health-related Quality of Life Questionnaire (MacNew) and the Short Form 36 (SF-36). Depressive and anxiety symptoms were assessed using the Hospital Anxiety and Depression Scale. Routine clinical data including disease severity were collected. RESULTS: The short and intermediate-term results revealed HRQL differences between PCI and CABG in the month immediately after intervention despite the almost identical reduction in angina severity over the first month in both groups. PCI was associated with a relatively rapid increase in HRQL in the first month, with little further change by 3 months. In contrast, after CABG there was an initial deterioration in HRQL, which then improved significantly. The change in depression and anxiety score uniquely accounted for most of the change in the SF-36 (6%, 64%) and MacNew scales (4%, 69%), whereas treatment accounted for less than 1% in any HRQL scale score changes. CONCLUSIONS: There appears to be evidence suggesting that HRQL changes after treatments in patients with CAD may be more strongly influenced by mood disturbance than by treatment methods.