Responses of people with coronary artery disease to common lawn-care tasks.

The primary purpose of the present study was to determine oxygen uptake (VO2) and heart rate (HR) responses of patients with coronary artery disease (CAD) to common lawn-care activities. The study was conducted in three phases. In phase I, 8 men with CAD performed 30 min of push motorized lawn mowing at a self-paced rate. In phase II, 9 men with CAD performed push (no power) mowing, trimming (power and manual), and raking for 8 min each. In phase III, age-matched men and women with and without CAD (9-11 per group) performed self-propelled motorized mowing and push motorized mowing. In phase I, VO2 averaged 17.3 (SEM 3.8) ml.kg-1.min-1 during 30 min of mowing. Relative effort was 68 (SEM 1) and 76 (SEM 4)% of treadmill maximal VO2 (VO2max) and HR, respectively. In phase II, mean VO2 ranged from 8.6 (SEM 0.4) with grass trimming to 22.2 (SEM 1.6) ml.kg-1.min-1 with push manual mowing. With self-propelled mowing at three speeds in phase III, mean VO2 of the CAD groups ranged from 9.5 (SEM 0.3) to 13.8 (SEM 1.4) ml.kg-1.min-1 and represented 37%-62% VO2max. The results indicated that lawn mowing is often performed at an exercise intensity recommended for aerobic exercise training; patients who achieve a treadmill peak capacity of 4 times resting metabolic rate (4 METs) should be able to perform self-propelled motorized lawn mowing (slow speed) and grass trimming at less than 80% peak VO2; and VO2 demands of lawn mowing can be adjusted by equipment selection and/or pace.

Long-term prognostic value of exercise testing in men and women from the Coronary Artery Surgery Study (CASS) registry.

Many prior studies involving a predominantly male population have demonstrated the importance of exercise test results in determining the outcome of patients with coronary artery disease. The prognostic significance of exercise testing in women is unknown. In our study, a total of 3,086 men and 747 women underwent maximal treadmill exercise testing, coronary angiography, and were prospectively followed for up to 16 years. They were divided into 3 groups (high, intermediate, and low risk) on the basis of exercise testing. Sixteen-year survival based on exercise test groups ranged from 38% to 61% in men and from 44% to 79% in women (p < 0.001). Among men, 12-year survival was enhanced by coronary artery bypass surgery versus medical therapy in the high-risk subgroup (69% vs 55%, respectively, p = 0.0025), but the 2 therapies were similar in the intermediate- and low-risk subgroups. Among women, neither medical nor surgical therapy resulted in improved 12-year survival rates in any of the 3 subgroups. These results suggest that exercise testing is helpful in assessing long-term survival in men and women. However, only exercise testing in men could identify a high-risk subset whose survival was enhanced by coronary artery bypass graft surgery.

Energy expenditure during household tasks in women with coronary artery disease.

The energy expenditure for and heart rate responses to common household tasks were determined in 26 older (mean age 62 +/- 2 years) women with coronary artery disease (CAD). Each activity was performed at a self-determined pace for 6 or 8 minutes. The average oxygen uptake (ml/kg/min) for each task evaluated was 6.5 for washing dishes, 6.8 for ironing, 7.2 for scrubbing pans, 8.6 for unpacking groceries, 9.5 for vacuuming, 9.8 for sweeping, 10.1 for mopping, 12.0 for changing bed linens, and 12.4 for washing the floor (hands and knees). None of the subjects reported angina. Mean relative oxygen uptake (i.e., percentage of peak response with treadmill testing) ranged from 31 +/- 2% for washing dishes to 62 +/- 3% for changing the bed linens and washing the floor. Percentage of peak treadmill heart rate ranged from 62 +/- 2% for washing dishes to 73 +/- 2% for washing the floor. In 4 of the more physically demanding household activities (i.e., vacuuming, mopping, washing the floor, and changing bed linens), the responses of 10 age-matched normal women were evaluated. The absolute and relative demands of the tasks were similar between the CAD and normal groups. Results indicate that the mean energy expenditure rate of common household tasks evaluated in this study range from 2 to 4 METs, suggesting that most women with CAD who are able to achieve > or = 5 METs during a treadmill exercise test without adverse signs or symptoms should be able to resume these activities.

Significance of silent myocardial ischemia during exercise testing in women: report from the Coronary Artery Surgery Study.

To evaluate the significance of silent myocardial ischemia during exercise testing in women compared to men, we analyzed the data on 1087 women and 3834 men who underwent exercise testing and coronary angiography from the Coronary Artery Surgery Study (CASS) registry. The patients were divided into three groups on the basis of the results of exercise testing: group 1, silent ischemia (253 women, 853 men); group 2, symptomatic ischemia (156 women, 1250 men); and group 3, no ischemia (678 women, 1731 men). The survival rate at 12 years for women was 80% for group 1, 75% for group 2, and 86% for group 3 (p = 0.0022); the survival rate for men was 69% for group 1, 69% for group 2, and 76% for group 3 (p < 0.001). In both men and women with silent ischemia, the 12-year survival rate was related to the severity of coronary artery disease (CAD) and ranged from 79% for women with one-vessel CAD to 46% for men with three-vessel CAD. Survival at 12 years was enhanced by coronary artery bypass graft surgery as compared to medical treatment in patients with silent ischemia and three-vessel CAD for men (61% vs 46%, respectively, p = 0.0014) but not for women (45% vs 50%, respectively, p = 0.98). These data suggest that silent ischemia in women and men adversely affects survival rate and that men may gain more benefit from coronary artery bypass graft surgery than women when three-vessel CAD is present.

Snow blowing and shoveling in normal and asymptomatic coronary artery diseased men.

We evaluated the oxygen uptake and heart-rate responses to self-paced snow blowing and snow shoveling in 10 men with asymptomatic coronary artery disease, 10 older normal men, and six younger normal men. Mean peak treadmill oxygen uptake in the three groups ranged from 26.4 +/- 1.1 to 47.3 +/- 3.9 ml/kg per min (P < 0.05). Oxygen uptake during snow blowing did not differ significantly among subject groups; values were 17.1 +/- 1.3, 17.7 +/- 1.1, and 17.2 +/- 0.9 ml/kg per min in the coronary artery disease, older normal, and younger normal groups, respectively. Oxygen uptake with snow shoveling was lower (P < 0.05) in those with coronary artery disease (18.4 +/- 1.0 ml/kg per min) than in the normal groups. In comparison with snow shoveling, oxygen uptake and heart rate did not differ (P = NS) from snow blowing in the coronary artery disease group but were lower (P < 0.05) with snow blowing in the two normal groups. The results indicate that men with asymptomatic coronary artery disease and relatively good functional work capacity perform snow blowing and snow shoveling at similar levels of oxygen uptake and heart rate.

Effect of aerobic training on baroreflex regulation of cardiac and sympathetic function.

To investigate the effect of aerobic exercise training on baroreflex regulation of muscle sympathetic nerve activity (MSNA) and cardiac R-R intervals in a middle-aged to older population, 10 healthy men > 40 yr of age underwent tests of autonomic function before and after 12 wk of high-intensity training. Cardiac and peripheral baroslopes were determined from the R-R interval vs. mean arterial pressure (MAP) and peroneal MSNA vs. diastolic pressure relationships, respectively, during sequential bolus injections of nitroprusside and phenylephrine. Maximal oxygen uptake increased (P < 0.05) 17% with training. Resting R-R interval increased (881 +/- 23 to 956 +/- 38 ms, P < 0.05), MAP decreased (96 +/- 2 to 91 +/- 3 mmHg, P < 0.05), and MSNA was unaltered (23.1 +/- 2.3 to 23.6 +/- 1.9 bursts/min) with training. Before and after training, respectively, cardiac baroslopes determined with decreasing (8.7 +/- 0.9 to 9.9 +/- 5.5 ms/mmHg) and increasing MAP (9.6 +/- 2.1 to 9.9 +/- 2.2 ms/mmHg) and the peripheral sympathetic baroslope (-3.3 +/- 0.4 to -3.5 +/- 0.6 bursts.min-1 x mmHg-1) did not differ. The results suggest that short-term aerobic training does not alter resting MSNA or neurocirculatory responses to baroreceptor challenges in middle-aged and older men.

Comparison of adaptations and compliance to exercise training between middle-aged and older men.

OBJECTIVE: To compare the rate and magnitude of physiologic and psychologic adaptations to aerobic training between middle-age and older men, to assess their interest in continued participation (> 6 months) in a supervised high-intensity training program, and to evaluate the safety of high-intensity training for older people. DESIGN: Before-after intervention trial. SETTING: Medical center in a Midwestern metropolitan city. PARTICIPANTS: Thirteen middle-age (35-50 years) and 14 older (60-71 years) normal men. INTERVENTION: Subjects trained on treadmills and leg cycle ergometers for 40 minutes 3 times per week. The intensity was increased to 85% of peak heart rate (HR) within the first 3 weeks of training. MEASUREMENT: Peak oxygen consumption, HR at submaximal work rates, three psychological tests, and election to continue in the supervised program. RESULTS: At 6 months of training, peak oxygen consumption had increased by 12% and 11% in the middle-aged and older groups, respectively, with 86% and 100% of this increase occurring within the first 3 months. Both groups showed comparable decreases in HR at submaximal work rates after 3 months of training with no further significant change from 3 to 6 months. None of the psychologic parameters evaluated changed significantly with 3 or 6 months of training in either group. More of the older (71%) than middle-aged (45%) men elected to continue in the supervised program after 6 months. CONCLUSIONS: The results of this study involving small groups of carefully screened middle-aged and older men suggest that the time course and magnitude of physiologic adaptations to aerobic training are similar between age groups when the training regimen is the same. Neither age group showed alterations in psychologic parameters nor experienced orthopedic injuries with training. The older group showed greater interest in continued participation in a supervised exercise program.

Physiologic responses to shoveling and thermal stress in men with cardiac disease.

To investigate the effect of temperature stress on responses to static-dynamic work in patients with ischemic heart disease (IHD), 10 men with IHD shoveled gravel for 30 min in a warm (29 degrees C), neutral (24 degrees C), and cold (-8 degrees C) environment (on separate days). A pace of 15 lifts.min-1 was set, and the load per lift approximated 5.5 kg. Heart rate (HR), oxygen consumption (VO2), and systolic (SBP) and diastolic blood pressures (DBP) were evaluated at 5-min intervals. Arrhythmias and ST-segment depression were evaluated by ambulatory electrocardiographic monitoring. At 30 min, VO2, SBP, and DBP were higher (P < 0.05) in the cold environment, and HR was higher (P < 0.05) in the warm environment compared with the neutral environment. HR increased (P < 0.05) from 5 to 30 min in all three conditions. The increase in HR was greater (P < 0.05) in the warm environment. None of the subjects reported angina or demonstrated electrocardiographic ST-segment changes during shoveling in any environment. The results indicate that low-risk patients with stable IHD show modest temperature-induced alterations in hemodynamic and VO2 responses during 30 min of moderate intensity (50-60% of peak VO2) static-dynamic work without adverse electrocardiographic responses or symptomatology.

Effect of enhanced preload with head-out water immersion on exercise response in men with healed myocardial infarction.

Head-out water immersion shifts venous blood to the central vasculature and heart and subsequently increases cardiac preload. In healthy men, cardiac output and stroke volume are greater during upright leg cycle exercise in water than on land. Heart rate is similar during work loads < 50% of peak oxygen consumption but is decreased in water at higher work intensities. To determine if men with myocardial infarction (MI) show a similar response, 15 men with a documented MI exercised upright on a leg cycle ergometer on land and immersed in water (31 +/- 1 degree C) to the level of the shoulders. Heart rate, cardiac output (carbon dioxide rebreathing procedure) and oxygen consumption were measured at rest and at work loads corresponding to approximately 40, 60 and 75% of peak oxygen consumption in both environments. At rest, cardiac output and stroke volume were elevated (p < 0.05) in water. During exercise, heart rate, cardiac output and stroke volume did not differ between water and land. When subjects were given beta-blocking medications (n = 8) and subjects with exercise-induced ST-segment depression (n = 5) were separately excluded from the analysis, water immersion still did not significantly change exercise responses. These results suggest that MI alters the normal cardiac response to increased preload during exercise. The alteration may involve reduced myocardial compliance or near-complete use of the Frank-Starling reserve, or both, during land exercise.

Baltimore Therapeutic Equipment work simulator: energy expenditure of work activities in cardiac patients.

The energy expenditure and hemodynamic responses to tasks performed on the Baltimore Therapeutic Equipment (BTE) work simulator were evaluated in men with coronary artery disease and compared to tasks performed at a laboratory workstation in which actual tools and equipment were used. Met units for the BTE work simulator and corresponding workstation tasks, respectively, were drill press operation, 1.5 +/- 0.1 and 1.5 +/- 0.3Mets; hammering, 2.3 +/- 0.3 and 3.4 +/- 0.8Mets (p < 0.05); repetitive lifting a 22.7kg weight load, 3.8 +/- 0.6 and 4.5 +/- 0.9Mets (p < 0.05); mechanic work in a supine position, 2.0 +/- 0.5 and 1.7 +/- 0.2Mets; sanding wood, 2.0 +/- 0.3 and 2.5 +/- 0.7Mets; sawing wood, 3.2 +/- 0.6 and 4.3 +/- 0.7Mets (p < 0.05); screwdriving, 2.2 +/- 0.3 and 2.5 +/- 0.5Mets (p < 0.05); shoveling, 5.45kg load 4.6 +/- 1.0 and 4.2 +/- 0.7Mets; sweeping, 1.7 +/- 0.2 and 3.0 +/- 0.4Mets (p < 0.05); and vacuuming, 2.7 +/- 0.7 and 2.9 +/- 0.5Mets. The results indicate that there is a tendency for the metabolic and hemodynamic responses to BTE work simulator tasks to be lower than that of the actual activity.

Effect of age and coronary artery disease on response to snow shoveling.

OBJECTIVES: The objective of this study was to evaluate the effect of age and coronary artery disease on responses to snow shoveling. BACKGROUND: Little information is available on the hemodynamic and metabolic responses to snow shoveling. METHODS: Sixteen men with asymptomatic coronary artery disease and relatively good functional work capacity, 13 older normal men and 12 younger normal men shoveled snow at a self-paced rate. Oxygen consumption, heart rate and blood pressure were determined. In nine men with coronary artery disease left ventricular ejection fraction was evaluated with an ambulatory radionuclide recorder. RESULTS: Oxygen consumption during snow shoveling differed (p < 0.05) among groups; it was lowest (18.5 +/- 0.8 ml/kg per min) in those with coronary artery disease, intermediate (22.2 +/- 0.9 ml/kg/min) in older normal men and highest (25.6 +/- 1.3 ml/kg/min) in younger normal men. Percent peak treadmill oxygen consumption and heart rate with shoveling in the three groups ranged from 60% to 68% and 75% to 78%, respectively. Left ventricular ejection fraction and frequency of arrhythmias during shoveling were similar to those during treadmill testing. CONCLUSIONS: During snow shoveling 1) the rate of energy expenditure selected varied in relation to each man's peak oxygen consumption; 2) older and younger normal men and asymptomatic men with coronary artery disease paced themselves at similar relative work intensities; 3) the work intensity selected represented hard work but was within commonly recommended criteria for aerobic exercise training; and 4) arrhythmias and left ventricular ejection fraction were similar to those associated with dynamic exercise.

Cardiac response to combined moderate heat and exercise in men with coronary artery disease.

The effect of moderate heat stress on cardiac performance during sustained moderate physical work was evaluated in men greater than or equal to 6 weeks after a cardiac event. Subjects (n = 10) performed upright leg cycle ergometer exercise at approximately 50% of peak oxygen uptake for up to 60 minutes in warm (30.0 +/- 0.9 degrees C) and thermoneutral (21.5 +/- 0.3 degrees C) environments. Cardiac output (carbon dioxide rebreathing method), left ventricular ejection fraction and relative left ventricular end-diastolic volume (portable nuclear VEST monitor) were periodically determined. In both environments, heart rate increased (p less than 0.05), stroke volume decreased (p less than 0.05), and cardiac output remained unchanged with exercise time. In the warmer environment, heart rate was increased (p less than 0.05) and stroke volume tended to be decreased (p less than 0.08), with no difference in cardiac output. In both environments, left ventricular ejection fraction did not change from minute 6 to 60 of exercise, whereas relative left ventricular end-diastolic volume decreased (p less than 0.05) with exercise time. Arterial blood pressure was unchanged from minute 6 to 60 in the warm environment. Arrhythmias were not altered by exercise time or environment, and no subjects had evidence of myocardial ischemia. The data indicate that although heart rate increased and stroke volume and relative left ventricular end-diastolic volume decreased with exercise time, cardiac output and left ventricular ejection fraction remained unchanged in both thermoneutral and warm environments.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluid-regulating hormones during exercise when central blood volume is increased by water immersion.

To examine the influence of an increase in central blood volume with head-out water immersion (WI) on fluid-regulating hormones during exercise, 10 healthy men underwent upright leg cycle exercise on land and with WI. Venous plasma renin activity and plasma venous concentrations of atrial natriuretic peptide, plasma aldosterone, and arginine vasopressin were determined at exercise intensities corresponding to approximately 40, 60, 80, and 100% peak oxygen consumption (VO2) and at minutes 1 and 5 of seated rest recovery within each environment. Peak VO2 did not differ on land and with WI. Atrial natriuretic peptide concentration was higher (P less than 0.05) and plasma renin activity was lower (P less than 0.05) in water than on land at 40% peak VO2 through minute 5 of recovery. Plasma aldosterone and arginine vasopressin concentrations were lower (P less than 0.05) in water at peak exercise and at minutes 1 and 5 of recovery. Osmolality and plasma sodium and potassium concentrations during exercise were similar in water and on land. The results indicate that WI alters the circulating levels of several hormones involved in fluid and electrolyte regulation during exercise. These hormonal alterations can best be explained by stimulation of low-pressure baroreceptors and atrial stretch due to increased central blood volume with head-out WI.

Significance of silent myocardial ischemia during exercise testing in patients with diabetes mellitus: a report from the Coronary Artery Surgery Study (CASS) Registry.

To evaluate the significance of ischemic ST depression without anginal chest pain during exercise testing among patients with diabetes mellitus, the data on 45 such patients from the Coronary Artery Surgery Study registry were analyzed. These patients (group 1, silent ischemia) were compared with 37 diabetic patients with both ischemic ST depression and chest pain (group 2, symptomatic ischemia), with 31 diabetic patients without ischemic ST depression or chest pain (group 3, no ischemia), and with 429 patients without diabetes who had silent ischemia during exercise testing. All patients had documented coronary artery disease (CAD) (greater than 70% diameter narrowing). The 6-year survival among patients with silent ischemia was worse in diabetic than nondiabetic patients (59 vs 82%, respectively, p less than 0.001). By contrast, the 6-year survival among patients without ischemia was similar among diabetic and nondiabetic patients (93 vs 85%, respectively, p = 0.476). Among diabetic patients, survival at 6 years with medical treatment was 59% for group 1, 66% for group 2 and 93% for group 3 (p = 0.008). Survival among subsets of patients with diabetes and silent ischemia (group 1) based on the extent of CAD and left ventricular function ranged from 100 to 32% (p = 0.093). The survival of the 45 patients with diabetes mellitus and silent ischemia (group 1) treated medically was compared with that of 28 patients receiving coronary artery graft bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and prognostic significance of silent and symptomatic ischemia after coronary bypass surgery: a report from the Coronary Artery Surgery Study (CASS) randomized population.

The prevalence and prognostic significance of postoperative myocardial ischemia, as detected by exercise testing, were prospectively assessed in 174 patients from the Coronary Artery Surgery Study (CASS) randomized surgical population who had exercise testing before and 6 months after coronary artery bypass graft surgery. Whereas the prevalence of symptomatic ischemia significantly decreased postoperatively (52% vs. 6%, p less than 0.001), the frequency of silent myocardial ischemia did not change (30% vs. 29%). Survival at 12 years after bypass surgery based on the 6-month postoperative exercise test results was significantly better for the 112 patients with no ischemia (80%) than for the 51 patients with silent ischemia (68%) or the 11 patients with symptomatic ischemia (45%). These data show that coronary artery bypass graft surgery diminishes the overall prevalence of symptomatic but not silent ischemia and that both silent and symptomatic ischemia adversely affect the postoperative prognosis of these patients.

Effect of increased central blood volume with water immersion on plasma catecholamines during exercise.

To examine the influence of an increase in central blood volume with head-out water immersion (WI) on the sympathoadrenal response to graded dynamic exercise, nine healthy men underwent upright leg cycle exercise on land and with WI. Plasma norepinephrine and epinephrine concentrations were used as indexes of overall sympathoadrenal activity. Oxygen consumption (VO2), heart rate, systolic blood pressure, and plasma concentrations of norepinephrine, epinephrine, and lactate were determined at work loads corresponding to approximately 40, 60, 80, and 100% peak VO2. Peak VO2 did not differ on land and with WI. Plasma norepinephrine concentration was reduced (P less than 0.05) at 80 and 100% peak VO2 with WI and on land, respectively. Plasma epinephrine and lactate concentrations were similar on land and with WI at the three submaximal work stages, but both were reduced (P less than 0.05) at peak exertion with WI. Heart rate was lower (P less than 0.05) at the three highest work intensities with WI. These results suggest that the central shift in blood volume with WI reduces the sympathoadrenal response to high-intensity dynamic exercise.

Cardiovascular regulation during head-out water immersion exercise.

Head-out water immersion is known to increase cardiac filling pressure and volume in humans at rest. The purpose of the present study was to assess whether these alterations persist during dynamic exercise. Ten men performed upright cycling exercise on land and in water to the suprasternal notch at work loads corresponding to 40, 60, 80, and 100% maximal O2 consumption (VO2max). A Swan-Ganz catheter was used to measure right atrial pressure (PAP), pulmonary arterial pressure (PAP), and cardiac index (CI). Left ventricular end-diastolic (LVED) and end-systolic (LVES) volume indexes were assessed with echocardiography. VO2max did not differ between land and water. RAP, PAP, CI, stroke index, and LVED and LVES volume indexes were significantly greater (P less than 0.05) during exercise in water than on land. Stroke index did not change significantly from rest to exercise in water but increased (P less than 0.05) on land. Arterial systolic blood pressure did not differ between land and water at rest or during exercise. Heart rates were significantly lower (P less than 0.05) in water only during the two highest work intensities. The results indicate that indexes of cardiac preload are greater during exercise in water than on land.

The role of exercise-induced silent myocardial ischemia in patients with abnormal left ventricular function. A report from the Coronary Artery Surgery Study (CASS) registry.

To evaluate the significance of ischemic ST depression without anginal chest pain (silent ischemia) during exercise testing among patients with abnormal left ventricular function, the data on 121 such patients with proven coronary artery disease (CAD) from the Coronary Artery Surgery Study (CASS) registry were analyzed. The patients with silent ischemia (group 1) were compared to: 124 CAD patients with both ST depression and angina (symptomatic ischemia, group 2); 159 CAD patients with neither ST depression nor angina (no ischemia, group 3); and 37 patients without CAD (controls). Survival at 7 years with medical therapy was similar for groups 1 (55%) and 2 (60%), but was substantially better for group 3 (73%, p = 0.001). Among group 1 patients with silent ischemia, survival was related to the severity of CAD (p = 0.001). Patients with silent ischemia and three-vessel CAD had a poor 7-year survival rate (37%) when treated medically. A comparable but non-randomized group of patients with silent ischemia and three-vessel CAD who underwent coronary artery bypass surgery had a much better 7-year survival rate (83%, p less than 0.0001). These results suggest that among patients with CAD and abnormal left ventricular function, silent ischemia adversely affects survival and can identify a higher risk subset of patients whose survival might be improved after coronary bypass surgery.

Weight carrying versus handgrip exercise testing in men with coronary artery disease.

The clinical merits of handgrip and weight carrying tests were compared in 30 patients with documented coronary artery disease. The static loads in the 2 tests were matched by percentage of maximal static effort and corresponded to 25 and 45% of maximal voluntary handgrip contraction and 25 and 45% of maximal 1-hand lift capacity. Each static load in both tests was continued for less than or equal to 3 minutes. At the 25% maximal effort stage, 93 and 90% of patients were able to complete 3 minutes of handgrip and weight carrying, respectively. Only 13 and 10% were able to complete 3 minutes at the 45% maximal effort stage with handgrip and weight carrying, respectively. Arm fatigue and an increase in diastolic blood pressure greater than 120 mm Hg were the predominant endpoints. Weight carrying resulted in significantly higher (p less than 0.05) heart rate, systolic blood pressure, pressure-rate product, ventilation and oxygen consumption compared to handgrip. Diastolic blood pressure responses did not differ between the tests. None of the patients demonstrated ischemic responses to either handgrip or weight carrying and the incidence of arrhythmias was rare. The diastolic blood pressure response to static effort is equally evaluated by handgrip and weight carrying tests. However, the greater myocardial oxygen demand, reflected by the pressure-rate product, in addition to the greater total body oxygen consumption, imposed by weight carrying, enhances the clinical application of the weight carrying test.

Risk of developing an acute myocardial infarction or sudden coronary death in patients with exercise-induced silent myocardial ischemia. A report from the Coronary Artery Surgery Study (CASS) registry.

To evaluate whether patients with silent myocardial ischemia during exercise testing are at increased risk for developing a subsequent acute myocardial infarction or sudden death, the data on 424 such patients with proven coronary artery disease (CAD) from the Coronary Artery Surgery Study (CASS) registry were analyzed. These patients (group 1) were compared with 456 other patients with CAD (group 2) who had both ischemic ST depression and angina pectoris during exercise testing and with 1,019 control patients without CAD. The probability of remaining free of a subsequent acute myocardial infarction or sudden death at 7 years was 80 and 91%, respectively, for group 1, 82 and 93%, respectively, for group 2 (difference not significant, compared with group 1), and 98 and 99%, respectively, for the control patients (p less than 0.001), compared with group 1 or 2). Among patients in group 1, the probability of remaining free of myocardial infarction and sudden death at 7 years was related to the severity of CAD and presence of left ventricular (LV) dysfunction, and ranged from 90% for patients with 1-vessel CAD and preserved LV function to 38% for patients with 3-vessel CAD and abnormal LV function (p less than 0.001). Thus, patients with either silent or symptomatic ischemia during exercise testing have a similar risk of developing an acute myocardial infarction or sudden death--except in the 3-vessel CAD subgroup, where the risk is greater in silent ischemia. The risk of patients with silent myocardial ischemia is based primarily on angiographic variables.