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To evaluate the response of patients with chronic atrial fibrillation (AF) to exercise and to demonstrate if prognosis could be predicted, 200 male patients (64 +/- 1 years) with AF were identified retrospectively who underwent resting echocardiography and symptom-limited treadmill testing. They were classified by underlying disease into three subgroups: hypertension or no underlying disease (LONE; n = 102), ischemic heart disease (IHD; n = 45) and history of congestive heart failure or valvular disease (CHF-VD; n = 53). Maximal exercise capacities for LONE, IHD and CHF-VD were (mean +/- 1 SEM) 8.0 +/- 0.3, 6.4 +/- 0.4 and 6.0 +/- 0.3 metabolic equivalents, respectively (p < 0.01), and resting left ventricular ejection fractions were 61.7 +/- 1.6, 60.1 +/- 2.2 and 49.5 +/- 1.9%, respectively (p < 0.01). Stepwise multiple regression analysis demonstrated that, except for group classification (R2 = 0.13, p < 0.01), no clinical, exercise or morphologic variables could predict exercise capacity. After a mean 39.1-month follow-up (range 1-78), 17 of the 200 had died from cardiovascular causes. The rate of cardiac death using Kaplan-Meier survival analysis was significantly greater in CHF-VD patients (p < 0.01). However, Cox hazard function and Kaplan-Meier survival analysis demonstrated that neither echocardiographic measurements of cardiac size or function at rest, nor exercise or clinical variables were significant predictors of outcome. AF patients with a history of CHF and/or VD demonstrated a reduced exercise tolerance ad a worse prognosis than those without morphologic heart disease or those with IHD.(ABSTRACT TRUNCATED AT 250 WORDS)

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Forty-two patients with angiographically documented left main coronary artery (LM) disease (luminal occlusion > or = 50%) and 30 patients with left main equivalent (LMEQ) disease (> or = 70% luminal occlusion of both the proximal left anterior descending artery and proximal left circumflex artery) were studied to determine the role of right coronary artery (RCA) involvement on exercise test responses and survival. Significant (> or = 70%) RCA stenosis was present in 30 (72%) of the 42 LM patients and 16 (53%) of the 30 LMEQ patients. No significant differences were observed between LM and LMEQ patients in any clinical or exercise variables or survival. Thus both groups were combined for analysis of the influence of RCA involvement (i.e., LM/LMEQ with RCA versus LM/LMEQ without RCA disease). Greater ischemic responses were observed in the LM/LMEQ group with significant stenosis of the RCA. The presence of RCA stenosis was associated with significantly greater horizontal or downsloping ST-segment depression during exercise (2.4 +/- 1.2 mm vs 1.3 +/- 1.4 mm; p < 0.001), and prolonged recovery time until normalization of the ST segment (3.2 +/- 1.4 min vs 2.0 +/- 1.9 min; p < 0.01). The LM/LMEQ without RCA disease group behaved like the subgroup with two-vessel disease, and responses of the LM/LMEQ group with RCA disease were similar to the group with three-vessel disease. The annual survival in LM/LMEQ with RCA disease was worse than that in LM/LMEQ without RCA disease (average annual mortality rates = 7.5% vs 1.0%, respectively; p = 0.05). Infarct-free survival in LM/LMEQ with RCA disease was also lower than that in LM/LMEQ without RCA disease. Thus although patients with LM and LMEQ were similar in terms of survival and exercise responses, the presence of RCA stenosis was associated with significantly greater ST-segment depression, a prolonged recovery time until normalization of the ST segment, a fivefold increase in the death rate, and higher morbidity from myocardial infarction over a 5-year period of follow-up. Involvement of the RCA should be considered when making decisions concerning medical-surgical management of patients with severe coronary artery disease.

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BACKGROUND: The objective of this study was to determine whether coronary angiographic findings and survival could be predicted using standard clinical and exercise-test data. METHODS: Five hundred and ninety-five men who had undergone both exercise treadmill testing and cardiac catheterization were followed for up to 5 years. Left main (LM) disease (> or = 50% stenosis) was present in 42 patients, whereas 30 patients had LM equivalent disease (> or = 70% stenosis of both the proximal left anterior descending and circumflex coronary artery disease (n = 152), one-vessel disease (n = 186), two-vessel disease (n = 118), three-vessel disease (n = 67), LM or LM equivalent disease without significant (> or = 70%) right coronary artery involvement (n = 26), and LM or LM equivalent disease with right coronary artery involvement (n = 46). RESULTS: ST-segment depression was more marked, whereas ejection fraction, maximal heart rate, maximal systolic blood pressure, and exercise capacity were lower in each group as disease severity worsened. Using Kaplan-Meier analysis, the subgroup with the poorest survival was found to be those with LM or LM equivalent disease with right coronary artery disease, and the next worse was the three-vessel disease group, in which survival was poorer than in all other subgroups (P < 0.01). Stepwise regression analysis revealed that the most powerful predictor for coronary artery disease severity was exercise-induced ST depression (P < 0.001), but it predicted survival poorly. History of congestive heart failure, low ejection fraction (50% or lower), and poor exercise capacity (5 metabolic equivalents or less) emerged as strong predictors of survival using stepwise Cox regression analysis (P < 0.001). CONCLUSION: Exercise-induced ST depression predicted the severity of angiographic disease but not survival, whereas the strongest predictors of survival were history of congestive heart failure, low ejection fraction, and poor exercise capacity.

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The evidence suggesting that regular exercise can help to prevent coronary artery disease is overwhelming. While some studies have suggested that exercise will not provide health benefits, our inactive population needs to pay heed to the substantial data presented by the many international health organisations suggesting the opposite. The American Heart Association Medical/Scientific Statement on Exercise emphasised the large role regular aerobic physical activity plays in the prevention of cardiovascular disease. Several human studies have also demonstrated the positive effects of long term exercise on the human heart. For example, it has been shown that a consistent exercise programme can lessen the impact of atherosclerotic plaques through increasing coronary artery diameter. Echocardiography studies on a training group of competitive swimmers have shown that exercise training can induce rapid changes in left ventricular dimensions and mass, which can ultimately lead to an increased stroke volume and increased maximal oxygen consumption. Studies on sedentary individuals have also demonstrated an increase in maximal oxygen uptake with a regular endurance exercise programme. In addition to these health benefits, habitual dynamic exercise can also decrease the likelihood of a cardiac event. Others have demonstrated a 50% lower incidence of coronary events in those individuals maintaining rigorous activity 2 days a week. With the preponderance of evidence revealing the health benefits of habitual exercise, it is striking to learn that more than 50% of the US population exercises for less than 20 minutes, 3 days a week. The widespread nature of this sedentary lifestyle makes inactivity an attributable fraction of the total risk factors associated with cardiac disease. The amount of exercise needed to reduce the risk of coronary artery disease is a minimum aerobic workout of 30 minutes, 4 to 5 times a week, such as a vigorous walk. Comprehensive programmes promoting exercise training should be implemented at a level appropriate to an individual's capacity and need.

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OBJECTIVES: The goal of this study was to create a nomogram, based on maximal exercise capacity (in metabolic equivalents [METs]) and age, for assessing a patient's ability to perform dynamic exercise to quantify the level of physical disability or relative capacity for physical activity. BACKGROUND: Providing an estimation of exercise capacity relative to age is clinically useful. Such an estimate can be derived from measured or estimated maximal oxygen uptake (in METs) from treadmill exercise testing and age. It is an effective means of communicating to patients their cardiopulmonary status, encouraging improvement in exercise capacity and quantifying disability. METHODS: Exercise test results of 1,388 male patients (mean age 57 years, range 21 to 89) free of apparent heart disease who were referred for exercise testing for clinical reasons were retrospectively reviewed. This referral group as well as subgroups of active (n = 346) and sedentary (n = 253) patients were analyzed to determine norms for age and for age by decades for exercise test responses, including METs, maximal heart rate and maximal systolic blood pressure. Regression equations were calculated from this information, and a nomogram for calculating degree of exercise capacity from age and MET level achieved by a patient was created. A similar analysis was performed in a separate group of 244 apparently healthy, normal male volunteers (mean age 45 +/- 14 years, range 18 to 72) who underwent exercise testing with direct measurement of expired gases. RESULTS: Equations for predicted METs for age were derived for the entire clinical referral group (METs = 18.0-0.15[Age]) and for the subgroups of active (METs = 18.7-0.15[Age]) and sedentary (METs = 16.6-0.16[Age]) patients. All results achieved statistical significance, with p values < 0.001. In the volunteer group of normal men who performed exercise testing with ventilatory gas exchange, the decline in maximal heart rate and METs with age was not as steep as in the referral group. Although the normal group confirmed nomograms published previously among similar subjects, the equations derived from the patients differed from those previously reported; in contrast to previous studies using healthy volunteers, the equations and nomograms for the referral group are more appropriate for patients typically referred for testing in a hospital or office-based internal medicine practice. CONCLUSIONS: Norms for METs based on age are presented as well as population-specific nomograms that enable physicians to assess patients' exercise capacity relative to their age group.

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The objective of this report is the development of a population-specific prediction rule based on clinical and exercise test data that would estimate the risk of cardiovascular death in patients selected for cardiac catheterization. Prospective data and follow-up information were obtained from patients who underwent cardiac catheterization soon after clinical assessment and exercise testing. Males (n = 588) referred for evaluation of coronary heart disease from 1984 to 1990 were selected after exclusion of patients with significant valvular heart disease and patients with prior cardiac surgery. Half had a prior myocardial infarction and half complained of typical angina pectoris. All patients performed a treadmill test and were selected for clinical reasons to undergo coronary angiography within 3 months. Over a mean follow-up period of 2.5 years (+/- 1.4 years), there were 39 cardiovascular deaths and 45 nonfatal myocardial infarctions. The Cox proportional hazards model demonstrated the following characteristics to be statistically significant independent predictors of time until cardiovascular death: history of congestive heart failure (hazards ratio of 4), ST depression on the resting ECG (hazards ratio of 3), and a drop in systolic blood pressure below the resting value during exercise (hazards ratio of 5). Exercise-induced ST depression was not associated with either death or nonfatal myocardial infarction. A simple score based on one item of clinical information (history of congestive heart failure), a resting ECG finding (ST depression), and an exercise test response (exertional hypotension) stratified our patients for 4 years after testing from 75% with a low risk (annual cardiac mortality rate of 1%), 17% with a moderate risk (annual mortality rate of 7%), and 1% with a high risk (annual cardiac mortality rate of 12%, with a hazards ratio of 20 and 95% confidence interval from 6 to 70X). It was concluded that the variables available from the usual noninvasive workup of patients with known or suspected coronary artery disease enable prediction of risk of cardiovascular death. Three quarters of those usually undergoing cardiac catheterization can be identified by simple noninvasive variables as being at such low risk that invasive intervention is unlikely to improve prognosis.

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OBJECTIVE: To develop prediction rules from clinical and exercise test data identifying patients at high and low risk for cardiovascular events among a group of male veterans. DESIGN: Prognostic study with prospective gathering of data and routine follow-up of consecutive patients referred for exercise testing. Patients only underwent noninvasive evaluation for coronary artery disease. No validation cohort is yet available. SETTING: A 1200-bed Veterans Affairs Medical Center. PATIENTS: Of 3609 men referred for exercise testing between 1984 and 1990, 2546 patients remained evaluable after exclusion of those who underwent subsequent cardiac catheterization, those with significant valvular heart disease, and those who had previous coronary artery bypass surgery. MEASUREMENTS: Evaluation included recording of clinical data on a standardized form and a standard treadmill test followed by assessment of cardiovascular events. RESULTS: During a mean follow-up period (+/- SD) of 2.75 (+/- 18) years, 119 cardiovascular deaths and 44 nonfatal myocardial infarctions occurred in 2546 patients. The Cox proportional hazards model showed the following characteristics to be statistically independent predictors of time until cardiovascular death: history of congestive heart failure or digoxin use, exercise-induced ST depression, change in systolic blood pressure during exercise, and exercise capacity. Using a simple score based on one item of clinical information (history of congestive heart failure or digoxin use) and three exercise test responses (ST depression, exercise capacity, and change in systolic blood pressure), 77% of patients were categorized as low risk (annual cardiac mortality rate, less than 2%), 18% as moderate risk (annual cardiac mortality rate, 7%), and 6% as high risk (annual cardiac mortality rate, 15%; hazard ratio, 10; 95% confidence interval, 6 to 17). This model has not yet been validated. CONCLUSIONS: Variables available from the usual non-invasive work-up of patients with known or suspected coronary artery disease can be used to predict future risk for cardiovascular death.

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To evaluate the response of patients with chronic atrial fibrillation (AF) to exercise, 79 male patients (mean age 64 +/- 1 years) with AF underwent resting two-dimensional and M-mode echocardiography and symptom-limited treadmill testing with ventilatory gas exchange analysis. Patients were classified by underlying disease into five subgroups: no underlying disease (LONE: n = 17), hypertension (HT: n = 11), ischemic heart disease (n = 13), cardiomyopathy or history of congestive heart failure (CHF: n = 26), and valvular disease (n = 12). A higher maximal heart rate than expected for age was observed (175 vs 157 beats/min), which was most notable in the LONE and HT subgroups. Maximal oxygen uptake (VO2 max) was lower than expected for age in all groups. Patients with CHF had a lower resting ejection fraction than all other patients (p < 0.001), a lower VO2 max, and a lower maximal heart rate than LONE and HT patients (p < 0.001). Stepwise regression analysis demonstrated that echocardiographic measurements at rest were poor predictors of VO2 max and VO2 at the ventilatory threshold. Among clinical, morphologic, and exercise variables, maximal systolic blood pressure accounted for the greatest variance in exercise capacity, but it explained only 35%. In patients with AF the higher than predicted maximal heart rates may be a compensatory mechanism for maintaining exercise capacity after the loss of normal atrial function. However, even in the absence of underlying disease, it does not appear to compensate fully for a compromised exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

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In a Veterans Affairs Medical Center, we studied 607 male patients to determine whether patterns and severity of coronary artery disease could be predicted by means of standard clinical and exercise test data. We found significant differences in clinical, hemodynamic, and electrocardiographic measurements among patients with progressively increasing disease severity determined by angiography. Left main disease produced responses significantly different from those of three-vessel disease only when accompanied by a 70% or greater narrowing of the right coronary artery. Discriminant function analysis revealed that the maximum amount of horizontal or downsloping ST depression in exercise and/or recovery was the most powerful predictor of disease severity, with 2-mm ST depression yielding a sensitivity of 55% and a specificity of 80% for prediction of severe coronary artery disease (three-vessel disease plus left main disease). Patients with increasingly severe disease also demonstrated a greater frequency of abnormal hemodynamic responses to exercise.

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While there is still much debate in the literature regarding the specific MET levels at which there are differences in survival, the following points have become clear with the growing body of reports in the literature. Exercise capacity seems to be an independent predictor of mortality, and when it is combined with other clinical, exercise, or angiographic data, it becomes very powerful in this regard. This relates to both overall mortality and to that from cardiovascular disease. There is still a need for the establishment of mortality data related to MET levels adjusted for age and activity status. A low exercise capacity of less than 6 METs indicates a higher mortality group, probably regardless of the underlying extent of coronary disease or left ventricular function. Analysis of the CASS data has indicated that these patients benefit from coronary artery bypass surgery with respect to survival. An exercise capacity of greater than 10 METs designates an excellent survival group, again despite the extent of coronary artery disease or left ventricular function. If 10 METs truly exerts a "protective effect" that obviates any survival benefit from coronary artery bypass surgery, this has enormous implications for cost containment and medical care. It is nonetheless important to remember that this level of exercise capacity does not imply the absence of either coronary disease or triple-vessel coronary disease. Exercise capacity is related to more than just cardiovascular fitness and integrity. It is dependent upon a combination of other physiologic components as well, including pulmonary function, health status of other organ systems, nitrogen balance, nutritional status, medications, orthopedic limitations, and others.(ABSTRACT TRUNCATED AT 250 WORDS)

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Animal studies have consistently shown increased heart strength, size, and vascularity in wild animals compared to domestic animals. While exercise has not been shown to decrease atherosclerosis in either animals or humans, it has been theorized that exercise makes the heart more resistant to ischemia through stimulation of collateral vessel formation and enlargement of already existent coronary arteries. In humans, the benefits and dangers of exercise have been researched with morphological, hemodynamic, and epidemiological studies. Many of these are discussed here as well as the national fitness recommendations made by various health organizations. A summary of the cardiovascular benefits of exercise as supported by the literature is then presented.

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