Continuum of cardiovascular performance across a broad range of fitness levels in healthy older men

BACKGROUND

Although it has become clear that habitual exercise in older individuals can partially offset age-associated cardiovascular declines, it is not known whether the beneficial effects of exercise training in older individuals depend on their prior fitness level.

METHODS AND RESULTS

Ten sedentary men (S), age 60.0 +/- 1.6 years (mean +/- SEM), who were carefully screened to exclude cardiac disease underwent exercise training for 24 to 32 weeks, and eight age-matched endurance-trained men (ET) stopped their exercise training for 12 weeks. All underwent treadmill exercise and rest and maximal cycle exercise upright gated blood pool scans at baseline and after the lifestyle intervention. Before the intervention, the treadmill maximum rate of oxygen consumption (Vo2max) was 49.9 +/- 1.9 and 32.1 +/- 1.4 mL.kg-1.min-1 in ET and S, respectively. During upright cycle exercise at exhaustion, although heart rate did not differ between groups, cardiac index, stroke volume index, ejection fraction, and left ventricular contractility index (systolic blood pressure/end-systolic volume index) all were significantly higher, and end-systolic volume index, diastolic blood pressure, and total systemic vascular resistance all were significantly lower in ET versus S. After the partial deconditioning of ET men, Vo2max fell to 42 +/- 2.2 mL.kg-1.min-1, and training of S increased Vo2max to 36.2 +/- 1.6 mL.kg-1.min-1. Training of S had effects on cardiovascular function that were similar in magnitude but directionally opposite those of detraining ET. All initial differences in cardiovascular performance at peak work rate between S and ET were abolished with the intervention. Across the broad range of fitness levels encountered before and after change in training status (Vo2max of 26 to 58 mL.kg-1.min-1), cardiac index, stroke volume index, end-systolic volume index, ejection fraction, and the left ventricular contractility index were all linearly correlated with Vo2max.

CONCLUSIONS

Exercise training or detraining of older men results in changes in left ventricular performance that are qualitatively and quantitatively similar, regardless of the initial level of fitness before the intervention.

Stress testing for coronary artery disease in the elderly

The elderly constitute an increasing percentage of patients evaluated and treated for coronary artery disease. Clinical and noninvasive evaluation are important in both the diagnosis and prognosis of coronary disease in the elderly, and stress testing is an important part of that evaluation. For older individuals capable of vigorous treadmill or cycle exercise, the exercise electrocardiogram, either alone or combined with radionuclide or echocardiographic imaging, remains an excellent diagnostic and prognostic tool. For the large percentage of elderly patients unable to perform adequate exercise, pharmacologic stress testing with dipyridamole, adenosine, or dobutamine is a valuable alternative. The clinician's challenge is to choose the most appropriate cardiac stress test for his or her patient from among the many alternatives available. Future studies comparing the accuracy and cost-to-benefit ratio of various stress tests with regard to the elderly will help achieve this goal.

Why do exercise-induced ventricular arrhythmias increase with age? Role of M-mode echocardiographic aging changes

BACKGROUND

Although advancing age is associated with a higher prevalence and complexity of exercise-induced ventricular arrhythmias (EIVA), the role of age-associated cardiac anatomic and functional characteristics in this relationship has not been explored.

METHODS

We performed both M-mode echocardiography and maximal treadmill exercise testing within two consecutive visits in 366 healthy volunteers ages 20 to 90 years from the Baltimore Longitudinal Study of Aging.

RESULTS

Simple (i.e., isolated) EIVA were detected in 79 subjects (21%) and complex EIVA (i.e., EIVA comprising > or = 10% of beats in any minute or occurring in runs) in another 17 (5%). Univariate predictors of any EIVA, whether simple or complex, were older age (p < .0001), greater LV mass index (p < .0001), male gender (p < .001), higher peak exercise systolic blood pressure (p = .003), and larger body surface area (p = .005). By multiple logistic regression analysis, only age (p = .0001) independently predicted the occurrence of EIVA. For complex EIVA alone, the strongest univariate predictors were age (p = .004), male gender (p = .008), lower maximal heart rate (p = .01), greater left atrial size (p = .03), and larger LV posterior wall thickness (p = .04); on multiple logistic regression, only older age (p = .03) and larger left atrial size (p = .04) independently predicted the presence of complex EIVA.

CONCLUSION

In healthy volunteers undergoing maximal treadmill exercise, greater LV wall thickness and mass are associated with the development of EIVA but they do not independently predict EIVA once the powerful effect of age is considered. The association between complex EIVA and left atrial dilatation may be mediated by higher LV end diastolic pressure and volume during exercise in subjects with larger left atria.

Left ventricular diastolic filling performance in older male athletes

OBJECTIVE

To determine whether older men who have undergone intensive endurance training over many years demonstrate less age-associated impairment of early diastolic left ventricular (LV) filling performance than their sedentary peers.

DESIGN

Cross-sectional prospective study.

SETTING

Community-dwelling research volunteers.

PARTICIPANTS

Sixteen older competitive male endurance athletes aged 52 through 76 years and 17 young (< 40 years) and 23 older (52 through 76 years) sedentary control subjects from the Baltimore Longitudinal Study of Aging.

INTERVENTION

All subjects underwent resting Doppler echocardiography and determination of maximal aerobic capacity (VO2max) during graded treadmill exercise. Doppler echocardiographic studies were interpreted without knowledge of the subject's age or exercise habits.

MAIN OUTCOME MEASURES

Doppler-derived measures of LV diastolic filling performance: peak early (E) filling velocity, peak late (A) filling velocity, ratio of peak E to peak A velocities (E/A), and atrial filling fraction.

RESULTS

Older athletes demonstrated higher VO2max (47 +/- 6 mL/kg per minute [mean +/- SD]) than either the young controls (41 +/- 7 mL/kg per minute) or older controls (30 +/- 7 mL/kg per minute) (P < .05) as evidence of their superior conditioning status. However, peak E diastolic LV filling velocity was higher in young controls (79 +/- 17 cm/s) than in older athletes (56 +/- 15 cm/s) or older controls (68 +/- 18 cm/s) (P < .001). This age difference persisted after normalizing peak E velocity for mitral stroke volume. Peak E/A ratio and atrial filling fraction were also similar in older athletes (1.2 +/- 0.5 and 0.41 +/- 0.1, respectively) and older controls (1.1 +/- 0.4 and 0.41 +/- 0.1, respectively), and differed significantly from corresponding values of 1.7 +/- 0.4 and 0.33 +/- 0.1 in young controls (P < .001 and P < .05, respectively). By multiple regression analysis, age but not treadmill VO2max was a significant predictor of peak E velocity, peak A velocity, peak E/A ratio, and atrial filling fraction.

CONCLUSION

Older men with a long history of intensive endurance training demonstrate impaired early diastolic LV filling similar to that of their sedentary peers. Thus, impairment of early diastolic filling appears to be intrinsic to normative aging and not secondary to the reduction in aerobic capacity that accompanies the aging process.

Prevalence and prognostic significance of exercise-induced supraventricular tachycardia in apparently healthy volunteers

The prevalence, characteristics, and prognostic significance of supraventricular tachycardia (SVT) occurring during maximal treadmill exercise testing were examined in 843 male and 540 female asymptomatic volunteers aged 20 to 94 years from the Baltimore Longitudinal Study of Aging who underwent exercise testing a mean of 2.3 times between 1977 and 1991. Exercise-induced SVT occurred during at least 1 test in 51 men (6.0%) and 34 women (6.3%), p = NS for gender. The 85 subjects with exercise-induced SVT were significantly older than the 1,298 free from this arrhythmia (66.0 +/- 13.5 vs 49.7 +/- 18.0 years, respectively, p < 0.001). The prevalence of SVT increased with age in men (p < 0.001) but not in women. Ninety-eight percent of the 141 discrete episodes of exercise-induced SVT were paroxysmal SVT, with heart rates varying from 105 to 290 beats/min (mean 186.3 +/- 43.3); only 16% were > 10 beats in duration and only 4% of subjects were symptomatic. Nearly half (44%) of SVT episodes occurred at peak effort. Coronary risk factors, echocardiographic left atrial size (3.3 +/- 6.7 vs 3.3 +/- 0.6 cm), and the prevalence of exercise-induced ischemic ST-segment depression (11% vs 13%) were similar in 85 subjects with SVT and 170 control subjects matched for age and sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of age on the cardiovascular response to dynamic upright exercise in healthy men and women

To examine whether age differentially modifies the physiological response to exercise in men and women, we performed gated radionuclide ventriculography with measurement of left ventricular volumes at rest and during peak upright cycle exercise in 200 rigorously screened healthy sedentary volunteers (121 men and 79 women) aged 22-86 yr from the Baltimore Longitudinal Study of Aging. At rest in the sitting position, age-associated declines in heart rate (HR) and increases in systolic blood pressure occurred in both sexes. Whereas resting cardiac index (CI) and total systemic vascular resistance (TSVR) in men did not vary with age, in women resting CI decreased 16% and TSVR increased 46% over the six-decade age span. Men, but not women, demonstrated an age-associated increase of approximately 20% in sitting end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and stroke volume index over this age span. Peak cycle work rate declined with age approximately 40% in both sexes, but at any age it was greater in men than in women even after normalization for body weight. At peak effort, ejection fraction (EF), HR, and CI were reduced similarly with age while ESVI and TSVR were increased in both sexes; EDVI increased 35% with age and stroke work index (SWI) rose 19% in men, but neither was related to age in women; and stroke volume index did not vary with age in either sex. When hemodynamics were expressed as the change from rest to peak effort as an index of cardiovascular reserve function, both sexes demonstrated age-associated increases in EDVI and ESVI and reductions in EF, HR, and CI. However, the exercise-induced reduction in ESVI and the increases in EF, CI, and SWI from rest were greater in men than in women. Thus, age and gender each have a significant impact on the cardiac response to exhaustive upright cycle exercise.

Rapid decline in FEV1. A new risk factor for coronary heart disease mortality

Coronary heart disease (CHD) is the leading cause of mortality in the United States. The present cohort study was conducted to determine whether rate of FEV1 loss independently predicts CHD mortality in apparently healthy men. White male Baltimore Longitudinal Study of Aging (BLSA) participants without CHD underwent clinical evaluation at 2-yr intervals; 883 had satisfactory pulmonary and lipid studies and returned for a least one visit. Cases were BLSA subjects without CHD on entry who died a "coronary death" (death from acute myocardial infarction, sudden death, or congestive heart failure in the presence of coronary artery disease). Forced expiratory maneuvers followed American Thoracic Society guidelines. Serum cholesterol, blood pressure, cigarette smoking, and body mass index were obtained from the BLSA database. There were 79 CHD deaths and 804 survivors during an average follow-up of 17.4 yr. After adjustment for age, initial FEV1% predicted, smoking status, hypertension, and cholesterol, a time-dependent proportional hazards model showed that cardiac mortality, but not all causes of mortality, generally increased with increasing quintile of FEV1 decline for the entire cohort (relative risk [RR] 2.92-5.13) and separately for the subset of never-smokers. Thus, excess CHD mortality follows a large decline in FEV1, independent of the initial FEV1% predicted, cigarette smoking, and other common CHD risk factors.

Diagnostic and prognostic value of stress testing in older persons

OBJECTIVE

To review the diagnostic and prognostic utility of exercise and pharmacologic stress testing in older individuals.

DATA SOURCE

A computer-assisted search of the literature, followed by a manual reference review of pertinent articles.

STUDY SELECTION

Studies addressing the use of exercise and pharmacologic stress testing for coronary artery disease (CAD) detection and prognosis were reviewed. Emphasis was placed on those studies applying these procedures to older populations.

DATA EXTRACTION

Pertinent data were extracted regarding the diagnostic and prognostic accuracy and safety of exercise and nonexercise stress testing techniques in older patients.

DATA SYNTHESIS

Available data from relevant articles were summarized and the merits and limitations of the available techniques discussed.

CONCLUSIONS

Numerous studies over the past 2 decades support the usefulness of the exercise ECG and exercise thallium-201 perfusion scan for detecting CAD in older populations. Although exercise echocardiography generally appears to have diagnostic and prognostic accuracy similar to thallium-201 imaging, greater technical difficulty with this technique is frequently encountered in older patients. Non-exercise forms of stress testing, particularly those employing pharmacologic agents such as dipyridamole, adenosine, or dobutamine, combined with either thallium-201 scintigraphy or echocardiography, allow accurate CAD diagnostic and prognostic assessment in even very frail older patients. Additional studies are needed to compare the accuracy and cost-benefit ratio of the many stress testing modalities now available for older patients.

Risk factors for exercise-induced silent myocardial ischemia in healthy volunteers

This study determined the risk factors for exercise-induced silent ischemia (SI) in 281 apparently healthy volunteers aged 40 to 87 years and compared their risk factor profiles with those of 132 patients with overt coronary artery disease (CAD). SI (concordant exercise-induced asymptomatic ST-segment depression on electrocardiography and perfusion defects on tomographic thallium-201 scintigraphy) was detected in 37 of 225 men (16%), versus 2 of 56 women (4%, p < 0.05). The prevalence of SI increased with age from 6% in men aged < 55 years to 18% in men aged 55 to 70 years, and to 25% in men aged > 70 years (p < 0.001). Compared with the 118 men with concordant normal exercise electrocardiogram and thallium scan (normals), men with SI were older (p < 0.001), and had a higher waist-to-hip ratio (p < 0.005), higher plasma triglyceride levels (p < 0.001), and lower high-density lipoprotein (HDL) cholesterol levels (p < 0.001). In stepwise logistic regression analysis, age, waist-to-hip ratio, and HDL levels were independent predictors of SI in men. Compared with 108 men with overt CAD, men with SI were younger (67 +/- 2 vs 73 +/- 1 years, p < 0.001) but had similar plasma lipids and waist-to-hip ratio. Thus, older age, male gender, abdominal obesity, and reduced HDL levels--all well-established risk factors for overt CAD--were risk factors for exercise-induced SI in these asymptomatic volunteers.

Effects of acute beta-adrenergic receptor blockade on age-associated changes in cardiovascular performance during dynamic exercise

The cardiovascular response to beta-adrenergic stimulation is markedly blunted with advancing age, and this blunting may underlie some of the prominent age-associated changes in the hemodynamic profile during dynamic exercise. To examine this hypothesis, we administered the nonselective beta-adrenergic receptor blocker propranolol (0.15 mg/kg IV) to 25 healthy normotensive men ages 28 to 72 years from the Baltimore Longitudinal Study of Aging (BLSA) immediately before maximal upright cycle ergometry with 99mTc gated cardiac blood pool scintigraphy. Their hemodynamic responses to exercise were compared with those of 70 age-matched healthy unmedicated male BLSA control subjects. The maximal cycle work rate achieved was similar in propranolol-treated men (158 +/- 32 W) and control subjects (148 +/- 32 W) and declined similarly with age in both groups. Hemodynamics at seated rest were not age-related in either group; however, propranolol-treated men had lower heart rates (HR), systolic blood pressure (SBP), ejection fraction, and cardiac index than control subjects but higher end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) by covariance analysis. At maximal effort, several striking age-drug interactions were evident: Propranolol caused a greater reduction in HR and greater increases in EDVI and stroke volume index (SVI) in younger than in older men. Hence, at maximal work rate, HR declined less with age in the propranolol group (0.46 versus 1.09 beats per minute per year, P < .05 by covariance analysis); EDVI and SVI decreased with age (0.27 and 0.48 mL/m2 per year, respectively) after propranolol compared with increases of 0.47 and 0.16 mL/m2 per year in control subjects, respectively, each P < or = .05 by covariance analysis. The left ventricular contractility index, SBP/ESVI, at exhaustion was reduced by propranolol to a greater extent in younger than older men. Thus, acute beta-adrenergic blockade reverses the age-associated ventricular dilation at end diastole and end systole observed during upright cycle exercise and blunts the decline in maximal HR and myocardial contractility. These data suggest that the age-associated declines in maximal HR and left ventricular contractility during vigorous exercise are manifestations of reduced beta-adrenergic responsivity with advancing age which is partially offset by exercise-induced ventricular dilation.

Cardiovascular responses to exhaustive upright cycle exercise in highly trained older men

It is unclear whether the markedly enhanced aerobic exercise capacity of older endurance-trained men relative to their sedentary age peers is mediated primarily by central or peripheral cardiovascular mechanisms. To address this question, we performed radionuclide ventriculography with respiratory gas exchange measurements during exhaustive upright cycle ergometry in 16 endurance-trained men aged 63 +/- 7 yr and in 35 untrained men of similar age. As expected, maximal O2 consumption during treadmill exercise was much higher in athletes than in controls. At rest and during fixed submaximal cycle work rates through 100 W, athletes demonstrated lower heart rates and greater stroke volume indexes than controls while maintaining similar cardiac indexes and O2 uptake (VO2). At exhaustion, athletes achieved 53% higher work rates and peak VO2 per kilogram body weight than the sedentary men. The higher peak VO2 in athletes was achieved by a 22.5% larger cardiac index and a 15.6% greater arteriovenous O2 difference. The larger peak cardiac index in the athletes than in sedentary controls was mediated entirely by a greater stroke volume index; peak heart rates were virtually identical. The athletes' greater stroke volume index was achieved through an 11% larger end-diastolic volume index and a 7% higher ejection fraction, both of borderline significance. At exhaustion, athletes demonstrated a lower systemic vascular resistance than controls, despite a higher value at rest. Athletes also showed greater exercise-induced increments in heart rate, stroke volume index, and cardiac index and a greater reduction in systemic vascular resistance from rest to maximal workload.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of body fat on exercise hemodynamics in sedentary older men

Morbid obesity is often associated with cardiac dilatation and left ventricular dysfunction. The present study investigated whether a similar relationship exists between mild and moderate obesity and left ventricular reserve function in 28 middle aged and older men (58.6 +/- 6.1 years, mean +/- SD). Subjects had a body mass index of 26.4 +/- 2.9 kg/m2, a percent body fat determined by hydrodensitometry ranging from 9.5% to 33.8%, and were carefully screened to exclude cardiovascular disease. Left ventricular function was assessed by gated blood pool scans at rest and during exhaustive upright cycle exercise. There were no significant relationships between resting or exercise cardiac volumes or ejection fraction with percent body fat; however, peak work rate/kg correlated inversely with percent body fat (r = -0.68, p < 0.0001). Heart rate reserve, defined as heart rate at peak work rate minus resting heart rate, declined significantly with increasing percent body fat (r = -0.47, p = 0.01). End diastolic volume index reserve also tended to decline with increasing percent body fat, but stroke volume index and cardiac index reserve were maintained because the decrease in end systolic volume index from rest to maximal exercise was greatest in those subjects with highest percent body fat (r = -0.41, p = 0.03). Therefore, rest and exercise left ventricular function are not related to percent body fat in healthy older men. However, older more obese men have a smaller increase in heart rate and end diastolic volume and a greater decrease in end systolic volume from rest to peak effort as a mechanism to augment exercise cardiac output.

ApoE4 polymorphism increases the risk for exercise-induced silent myocardial ischemia in older men

The apolipoprotein (apo) E4 polymorphism is associated with increased risk for symptomatic coronary artery disease (CAD). This study examines whether the apo epsilon allele is associated with an increased risk for exercise-induced silent myocardial ischemia (SI) in healthy, older (62 +/- 7 years; mean +/- SD), normocholesterolemic, nonsmoking male volunteers. The apo epsilon 4 allele was present in 20 of 45 (44%) men with SI on graded exercise treadmill testing compared with 22 of 127 (17%) men of comparable age with normal exercise tests (P < .001), resulting in a crude relative risk of 2.57 (95% confidence limits, 1.57 to 4.23) for SI in men with the apo epsilon 4 allele compared with those without the epsilon 4 allele. Although the lipoprotein lipid levels did not differ between men with normal exercise tests and those with SI, the men with the apoE 4/3 phenotype had higher total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels than those with the apoE 2/3 and 3/3 phenotypes (P < .05). Men with SI and the apoE 4/3 phenotype were older (64 +/- 5 versus 57 +/- 8 years, P < .01) and leaner (P < .01) than the normal non-SI men with the apoE 4/3 phenotype. The older age of the men with SI and the apoE 4/3 phenotype is consistent with a progression of atherosclerosis over time. Men with SI and the apoE 3/3 phenotype were of comparable age and body composition to apoE 3/3 phenotype men with normal exercise tests. Thus, even in the presence of normal LDL-C levels, the apo epsilon 4 allele may predispose older men to SI.

Effects of age and aerobic capacity on arterial stiffness in healthy adults

BACKGROUND

It has been well established that arterial stiffness, manifest as an increase in arterial pulse wave velocity or late systolic amplification of the carotid artery pressure pulse, increases with age. However, the populations studied in prior investigations were not rigorously screened to exclude clinical hypertension, occult coronary disease, or diabetes. Furthermore, it is unknown whether exercise capacity or chronic physical endurance training affects the age-associated increase in arterial stiffness.

METHODS AND RESULTS

Carotid arterial pressure pulse augmentation index (AGI), using applanation tonometry, and aortic pulse wave velocity (APWV) were measured in 146 male and female volunteers 21 to 96 years old from the Baltimore Longitudinal Study of Aging, who were rigorously screened to exclude clinical and occult cardiovascular disease. Aerobic capacity was determined in all individuals by measurement of maximal oxygen consumption (VO2max) during treadmill exercise. In this healthy, largely sedentary cohort, the arterial stiffness indexes AGI and APWV increased approximately fivefold and twofold, respectively, across the age span in both men and women, despite only a 14% increase in systolic blood pressure (SBP). These age-associated increases in AGI and APWV were of a similar magnitude to those in prior studies of less rigorously screened populations. Both AGI and APWV varied inversely with VO2max, and this relationship, at least for AGI, was independent of age. In endurance trained male athletes, 54 to 75 years old (VO2max = 44 +/- 3 mL.kg-1.min-1), the arterial stiffness indexes were significantly reduced relative to their sedentary age peers (AGI, 36% lower; APWV, 26% lower) despite similar blood pressures.

CONCLUSIONS

Even in normotensive, rigorously screened volunteers in whom SBP increased an average of only 14% between ages 20 and 90 years, major age-associated increases of arterial stiffness occur. Higher physical conditioning status, indexed by VO2max, was associated with reduced arterial stiffness, both within this predominantly sedentary population and in endurance trained older men relative to their less active age peers. These findings suggest that interventions to improve aerobic capacity may mitigate the stiffening of the arterial tree that accompanies normative aging.

Additive effects of age and silent myocardial ischemia on the left ventricular response to upright cycle exercise

To separate the independent effects of age and silent myocardial ischemia on the left ventricular response to aerobic exercise, maximal upright cycle ergometry was performed in three groups: 8 clinically healthy older men [76 +/- 3 (SE) yr] with ischemic electrocardiogram (ECG) and Tl scan responses to prior maximal treadmill exercise (old silent ischemic subjects), 16 age-matched men with normal ECG and Tl scan responses (old controls), and 21 healthy young (33 +/- 1 yr) men (young controls). Although the left ventricular ejection fraction, end-diastolic volume index, and end-systolic volume index were similar in the three groups at rest, with increasing work loads there was a progressive increase in the end-diastolic volume index and a blunted decline in end-systolic volume index in the two older groups, which was most apparent in the old silent ischemic subjects. Thus, at peak effort, end-diastolic volume index was largest in old silent ischemic subjects (101 +/- 6 ml/m2), intermediate in old controls (85 +/- 6 ml/m2), and smallest in young controls (67 +/- 3 ml/m2) (P < 0.002); conversely, left ventricular ejection fraction was highest in young controls (85 +/- 2), intermediate in old controls (76 +/- 3), and lowest in the old silent ischemic group (66 +/- 2) (P < 0.001). At exhaustion the peak systolic pressure-end-systolic volume index was significantly lower in the silent ischemic group than in young controls (6 +/- 1 vs. 25 +/- 4 mmHg.ml-1 x m-2, respectively; P < 0.001) with the old controls in between (16 +/- 5 mmHg.ml-1 x m-2).(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension in the elderly: age- and disease-related complications and therapeutic implications

Effective treatment of hypertension in the elderly requires an understanding of both the progressive course of the disease and the impact of aging on the cardiovascular system, including physiological, genetic, lifestyle, and environmental factors. Review of the literature that has attempted to define the impact of an "aging process" on cardiovascular structure and function reveals a diversity of findings and interpretations. However, in general, normotensive elderly subjects exhibit the heart and vascular characteristics of "muted" hypertension, including many features of younger hypertensive patients: cardiac hypertrophy, diminution in resting left ventricular early diastolic filling rate, increased arterial stiffness and aortic impedance, diminution in the baroreceptor reflex, a diminished response to catecholamines and diminished renal blood flow, and an increase in peripheral vascular resistance (PVR). Treatment of elderly hypertensives is more challenging because of the greater likelihood of the presence of concomitant diseases, most importantly, coronary and peripheral atherosclerosis, renal dysfunction, and diabetes mellitus. Isolated systolic hypertension (ISH), the most common form of hypertension in the elderly, has also been clearly shown to be an important predictor of cardiovascular morbidity and mortality, including coronary artery disease, congestive heart failure, and stroke. Treatment of ISH has been shown to lower systolic pressure safely and effectively in the elderly. By reducing PVR, and possibly the arterial stiffness, and thus the early reflected pulse waves, vasodilators, including calcium antagonists, may lower these three components of arterial impedance, and hence lower the arterial load on the heart. The cardiac hypertrophy and reduced left ventricular filling rate associated with hypertension in older individuals can also be ameliorated, to some extent, by calcium channel blockers.

Age-related decline in left ventricular filling at rest and exercise

To determine whether the age-associated decline in resting left ventricular diastolic filling persists during aerobic exercise, rest and bicycle exercise filling indexes were measured from gated radionuclide blood pool scans in 88 healthy men aged 22-82 yr. To evaluate the effect of physical conditioning status on these age-related changes, a subset of the subjects consisted of endurance-trained senior athletes with a maximal O2 consumption of 50.5 +/- 5 compared with 32.6 +/- 7 ml.kg-1 x min-1 in age-matched controls. The contribution of beta-adrenergic stimulation to exercise-induced changes in filling was also evaluated by the administration of intravenous propranolol to another subset before testing. Peak filling rate increased progressively at all ages with increasing exercise work loads. The peak filling rates at rest, 50% maximal exercise, and maximum exercise inversely correlated with age (r = -0.64, -0.53, -0.64, respectively). Rest and exercise filling indexes in senior athletes were similar to those of sedentary older subjects. Propranolol decreased exercise peak filling rates in young (37.2 +/- 7.5 yr) but not in older (62.1 +/- 6 yr) subjects. Therefore, filling rates increase with exercise in both young and older healthy men, but age differences persist at comparable relative work loads. This decline is not secondary to a decline in physical conditioning status but appears to be related to a decrease in beta-adrenergic responsiveness in older individuals.

Long-term prognostic significance of ambulatory electrocardiographic findings in apparently healthy subjects greater than or equal to 60 years of age

To determine the long-term prognostic significance of frequent or complex ectopic beats and ST-segment changes on 24-hour ambulatory electrocardiogram (ECG) in apparently healthy older subjects, 98 volunteers were followed up from the Baltimore Longitudinal Study of Aging who were 60 to 85 years old and free of cardiac disease by history, physical examination and maximal treadmill testing at the time of ambulatory ECG between 1978 and 1980. Over a mean follow-up period of 10 years, coronary events developed in 14 subjects: angina pectoris in 7, nonfatal myocardial infarction in 3 and sudden cardiac death in 4. The incidence of coronary events did not differ significantly between subjects who developed the following arrhythmias and those who did not, respectively: greater than or equal to 30 supraventricular ectopic beats in any hour, 18 vs 13%; greater than or equal to 100 supraventricular ectopic beats in 24 hours, 20 vs 12%; paroxysmal atrial tachycardia, 15 vs 14%; greater than or equal to 30 ventricular ectopic complexes (VECs) in any hour, 17 vs 14%; greater than or equal to 100 VECs in 24 hours, 18 vs 14%; or repetitive VECs, 20 vs 13%. The mean 24-hour heart rate (75 +/- 8 vs 72 +/- 9 beats/min) as well as the maximal (116 +/- 20 vs 111 +/- 18 beats/min) and minimal (51 +/- 6 vs 53 +/- 7 beats/min) heart rate also did not differ between the coronary event and non-event groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and prognostic significance of exercise-induced silent myocardial ischemia in apparently healthy subjects

The addition of thallium-201 (201Tl) scintigraphy to traditional exercise electrocardiography (ECG) was assessed to determine whether the combination was a more accurate predictor of future coronary events than exercise ECG alone in an apparently healthy population. There were 407 participants enrolled in the Baltimore Longitudinal Study of Aging. The participants, who had no clinical or resting ECG evidence of coronary artery disease, underwent 201Tl scintigraphy immediately following maximal treadmill exercise. Four subsets of subjects were derived: (1) negative ECG and negative 201Tl; (2) positive ECG and negative 201Tl; (3) negative ECT and positive 201Tl; (4) positive ECG and positive 201Tl. A total of 66 individuals (16%) had positive ECGs and 55 (14%) had positive 201Tl scans. Concordant positive results in both tests were seen in 23 subjects (6%), with a 7-fold increase in prevalence from ages 40-59 years to greater than 80 years. Over a mean follow-up of 4.6 years, cardiac events (angina pectoris, myocardial infarction, or cardiac death) occurred in 40 of 407 volunteers (9.8%). Analysis revealed a 48% incidence of cardiac events in the subset with concordant abnormal ECG and 201Tl test results versus an event rate of 3-12% for the other 3 groups (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl scan were independent predictors of future coronary events. A concordant abnormal ECG and 201Tl response imparted a 3.6-fold relative event risk. Although not practical for screening the general population, combined exercise ECG and 201Tl scintigraphy warrants further investigation as a diagnostic strategy in high-risk subsets with additional coronary risk factors.

Cholesterol as a risk factor for coronary heart disease in elderly men. The Baltimore Longitudinal Study of Aging

In order to explore the relationship of cholesterol to coronary heart disease (CHD), defined as angina pectoris, myocardial infarction, and sudden coronary death, in older men, a group of 1052 men, participants in the Baltimore Longitudinal Study on Aging, were examined. Subjects were stratified into three age groups, 28 to 64, 65 to 74, and 75 to 97 years old. In all three age groups, cholesterol was a significant risk factor for CHD. In the oldest age group (n = 250), the relationship between cholesterol and risk was linear (P = .003) as opposed to younger age groups where the relationship was exponential. This study extends the age range in which hypercholesterolemia has been shown to be associated with CHD to include the 75- to 97-year range.

Effect of age of entry to a longitudinal study on cross-sectional determination of cardiovascular disease

Cross-sectional analysis from longitudinal studies for a specific age can include subjects who entered the study at different ages (i.e. younger individuals followed to the age of interest, and those who entered at the age of interest). This represents a potential source of bias, since the state of health at a given age may vary based on age at entry. We investigated such bias as it affected the prevalence of cardiovascular diagnoses in men from the Baltimore Longitudinal Study of Aging. Subjects who entered the study in either their 60's, 70's or 80's (New subjects) were compared to individuals who entered the study at an age at least 10 years younger and were followed into these same age decades (Continuing subjects). No differences were found between New and Continuing subjects for coronary heart or cerebrovascular diseases, but were present for hypertension. The greater prevalence of hypertension in Continuing subjects appeared to be of minor clinical importance because other diagnostic differences were absent. The study found evidence for potential selection bias based on age at entry, but the consequence of the bias appeared to be slight.

Frequency and importance of postprandial blood pressure reduction in elderly nursing-home patients

OBJECTIVE

To determine the frequency and importance of postprandial reductions in systolic blood pressure in debilitated, elderly patients receiving nursing home care.

DESIGN

Cohort study.

SETTING

Community-based, university-affiliated, teaching nursing home.

PATIENTS

A total of 113 volunteer nursing-home residents with a mean (+/- SD) age of 78 +/- 9 years; seven residents who refused the test meal served as controls.

INTERVENTION

Participants had sequential blood pressure measurements for 90 minutes after the administration of a standardized meal.

MEASUREMENTS AND MAIN RESULTS

Of 113 patients, 109 (96%) showed a postprandial reduction in systolic blood pressure (mean reduction, 17.9 +/- 15.5 mm Hg) within 75 minutes; 41 patients (36%) had a reduction in systolic blood pressure of more than 20 mm Hg. Twelve patients (11%) had a reduction in systolic blood pressure to less than 100 mm Hg (mean systolic blood pressure, 88 +/- 6.4 mm Hg); two of these patients became acutely symptomatic. Multiple regression analysis showed that higher premeal systolic blood pressure, a history of syncope, treatment with vasodilators, and dependent posture of the lower extremities during the postprandial period were all associated with a more severe postprandial decline in systolic blood pressure. Systolic blood pressure in noneating control subjects did not change during the same observation period. No significant differences in the mean systolic blood pressure nadir were found between the 14 patients who died during the follow-up period (mean follow-up, 6.1 +/- 3.8 months) and those who survived.

CONCLUSION

Postprandial reductions in systolic blood pressure among elderly nursing-home patients are common, often large, and potentially symptomatic, but they do not generally presage subsequent intermediate-term mortality.

Effect of postural stress on left ventricular performance using the continuous-wave Doppler technique

To evaluate the effect of postural shifts on continuous-wave Doppler indices of left ventricular performance in normal man, we recorded Doppler signals suprasternally in 69 healthy volunteers, ranging in age from 20 to 86 years, in the supine position and 2 min after assumption of sitting and standing postures. All indices decreased progressively with increasing orthostasis: peak acceleration (PKA): 15.6 +/- 4.5 m/s2 to 14.0 +/- 4.0 m/s2 to 13.6 +/- 4.6 m/s2; peak velocity (PKV): 0.64 +/- 0.18 m/s to 0.58 +/- 0.17 m/s to 0.56 +/- 0.17 m/s; stroke distance (SD): 11.4 +/- 3.7 cm to 9.8 +/- 3.4 cm to 8.0 +/- 2.8 cm; SD x heart rate (VIH): 717 +/- 272 cm to 655 +/- 268 cm to 572 +/- 217 cm, from supine to sitting to standing, respectively (p less than 0.001). In contrast heart rate increased modestly from 62.4 +/- 10.0 bpm supine, to 66.9 +/- 12.4 bpm sitting, to 71.3 +/- 9.9 bpm standing (p less than .001). Similar postural changes in Doppler variables were seen in all three age groups (20 to 44 years; 45 to 64 years; and 65 to 86 years). Thus, orthostasis in normal subjects is accompanied by a reduction in all continuous-wave Doppler indices of left ventricular performance, regardless of age.

Effect of maintenance digoxin therapy on aerobic performance and exercise left ventricular function in mild to moderate heart failure due to coronary artery disease: a randomized, placebo-controlled, crossover trial

Despite 200 years of use, the ability of digitalis glycosides to improve exercise capacity in patients with congestive heart failure remains controversial, partly because of imprecise end points and suboptimal study design. Therefore, this question was examined in 10 ambulatory patients (8 men and 2 women) aged 46 to 70 years (mean 57.8) in sinus rhythm with mild to moderate chronic stable congestive heart failure due to coronary artery disease and systolic left ventricular dysfunction (ejection fraction 32 +/- 12). All underwent maximal treadmill exercise with respiratory gas analysis and upright cycle ergometry with gated radionuclide angiography after 4 weeks of digoxin or placebo therapy, administered in a randomized double-blind crossover protocol. Neither treadmill exercise duration (7.7 +/- 2.3 versus 7.3 +/- 2.7 min) nor peak oxygen consumption (18.7 +/- 3.7 versus 18.4 +/- 5.4 ml/kg per min) differed between digoxin and placebo regimens. However, the change in peak oxygen consumption induced by digoxin was inversely related to the peak oxygen consumption during placebo therapy (r = -0.64, p less than 0.05). At maximal treadmill effort, heart rate (138 +/- 16 versus 141 +/- 21 beats/min), oxygen pulse (10.3 +/- 2.1 versus 9.9 +/- 2.2 ml/beat), ventilation (40.3 +/- 10.6 versus 42.0 +/- 10.8 liters/min) and ventilatory equivalent (29.4 +/- 4.8 versus 31.5 +/- 6.8) did not differ between digoxin and placebo treatment, although systolic blood pressure was higher during digoxin therapy (163.0 +/- 23.1 versus 153.2 +/- 25.3 mm Hg, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina pectoris in the elderly

Although the ability to document angina pectoris in the elderly patient may be compromised by atypical symptoms, limited activity levels, and blunted recall, anginal symptoms convey a similar adverse prognosis regardless of age. In general, the therapeutic approach to the older anginal patient should be dictated more by achievement of symptomatic relief than by considerations of long-term survival. No randomized trial exists to guide the decision of medical versus coronary artery bypass surgery versus angioplasty in the older patient with coronary artery disease; symptomatic relief, however, appears greater after revascularization procedures.

Age as independent determinant of glucose tolerance

It has been proposed that the decline in glucose tolerance with age is not a primary aging effect but is secondary to a combination of other age-associated characteristics, i.e., disease, medication, obesity, central and upper-body fat deposition, and inactivity. To test this hypothesis, we first eliminated from analysis the Baltimore Longitudinal Study of Aging participants with identifiable diseases or medications known to influence glucose tolerance. Seven hundred forty-three men and women, aged 17-92 yr, remained for analysis. As indices of fatness, body mass index and percent body fat were determined. As indices of body fat distribution, waist-hip ratio and subscapular triceps skin-fold ratio were calculated. As indices of fitness, physical activity level, determined by detailed questionnaire, and maximum 02 consumption were calculated. We tested whether the effect of age on glucose tolerance remains when data were adjusted for fatness, fitness, and fat distribution; 2-h glucose values were 6.61, 6.78, and 7.83 mM for young (17-39 yr), middle-aged (40-59 yr), and old (60-92 yr) men and 6.22, 6.22, and 7.28 mM for the three groups of women, respectively. The differences between the young and middle-aged groups were not significant, but the old groups had significantly higher values than young or middle-aged groups. Fatness, fitness, and fat distribution can account for the decline in glucose tolerance from the young adult to the middle-aged years. However, age remains a significant determinant of the further decline in glucose tolerance of healthy old subjects.

The age-associated decline in glomerular filtration in healthy normotensive volunteers. Lack of relationship to cardiovascular performance

Whether the well-documented age-associated decline in the glomerular filtration rate, manifest as a decline in creatinine clearance, is secondary to an age-related change in cardiovascular performance is at present unknown. To answer this question, we measured arterial blood pressure, 24-hour creatinine clearance, and cardiac output determined from gated cardiac blood pool scans in the sitting position in healthy normotensive men (n = 75) and women (n = 42) (ages 25 to 82 years), from the Baltimore Longitudinal Study on Aging. These subjects were selected for the absence of cardiovascular disease, renal disease, and confounding medications. By linear regression analysis, creatinine clearance, expressed in mL/min/m2, declined cross-sectionally with age (creatinine clearance = 90 -0.33[age], r = .31, P less than .001), whereas systolic blood pressure in mm Hg increased with age (systolic blood pressure = 111 + 0.27[age], r = .30, P less than .001); cardiac output in L/min/m2 did not vary with age (r = .03, P = .74). In stepwise multiple regression analysis with age, cardiac index, and systolic blood pressure as independent variables and creatinine clearance as the dependent variable, only age was a significant predictor of creatinine clearance. (F = 11.31, DF + 116, r = .30, P less than .001). Thus, the age-associated decline in creatinine clearance is not modulated by changes in cardiac index or systolic blood pressure in healthy normotensive subjects.

Plasma levels of estradiol, testosterone, and DHEAS do not predict risk of coronary artery disease in men

Prior studies have reported men with coronary artery disease (CAD) to have elevated plasma levels of estrogens and reduced concentrations of dehydroepiandrosterone (DHEA) or DHEA-sulfate (DHEAS). We investigated whether gonadal steroids or DHEAS are risk factors for CAD in men, using a prospective design, in a well characterized population studied at regular intervals. We studied 46 men (Cardiac group) who developed CAD and 124 men (Control group) who remained free of CAD (mean follow-up, 9.5 years). We measured testosterone (T), estradiol (E2), and DHEAS, as well as plasma binding of T and E2, in samples stored before the onset of CAD (Cardiac group) or at matched times (Control group). Body mass index, blood pressure, and total serum cholesterol were measured at each visit. Both systolic blood pressure (SBP; P less than 0.001) and cholesterol (P less than 0.001) were increased in the Cardiac group, but no significant differences were found in total or free T or E2, the ratio of E2/T, or DHEAS between the two groups. The difference in cholesterol was significant only in men less than or equal to 65 years old (P less than 0.001), and SBP only in men greater than 65 years old (P less than 0.005). Cholesterol (P less than 0.05) and E2 (P less than 0.001) appeared to decrease with age in the Cardiac, but not the Control, group. Moreover, total (P less than 0.01) and free E2 (P less than 0.05) were lower only in Cardiac men less than or equal to 55 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-associated changes in the components of atrioventricular conduction in apparently healthy volunteers

The mechanism for the prolongation of P-R interval associated with advancing age is undefined. Using a high-resolution ECG (Marquette MAC-1) to signal average 512 cardiac cycles, we examined 185 healthy volunteers aged 20-83 years from the Baltimore Longitudinal Study of Aging with normal rest and exercise ECGs and a resting P-R interval less than 210 ms. Among the 161 subjects with visible His bundle activity, P-R interval increased with age (p less than .001). This increase was due entirely to prolongation of the interval between the P wave onset and His bundle potential, i.e., the P-H interval, (p less than .001) with no age-associated change in the H-V interval, p = NS. The P-H interval prolongation with age was localized to the P-R segment proximal to His bundle activation (p less than .001). In a separate group of 7 asymptomatic older men (mean age = 71 yr), with first-degree atrioventricular (A-V) block on standard ECG (mean PR = 238 +/- 14 ms), the P-H interval (193 +/- 21, vs 136 +/- 18 ms, p less than .001) and proximal P-R segment (82 +/- 19) vs 33 +/- 15 ms, p less than .001) but not the H-V interval (45 +/- 11 vs 40 +/- 9 ms, p = NS) were longer than in 25 age-matched men without A-V block. Thus, the modest age-associated prolongation of the P-R interval is localized to the proximal P-R segment, probably reflecting delay within the atrioventricular junction. A similar but more striking delay in the proximal P-R segment is responsible for first degree A-V block in apparently healthy older men.

Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction between left ventricular end-diastolic and end-systolic volumes in normal humans

The extent to which the end-systolic volume (ESV) "follows" the end-diastolic volume (EDV) when the latter changes in response to various perturbations is a major determinant of the cardiac ejection fraction (EF) and has not been studied in humans. We measured EDV, ESV, and EF, determined by gated blood pool scans, during a change in posture from the supine to the upright seated position and during graded upright bicycle exercise. The experimental group consisted of 119 healthy individuals (79 males and 40 females) ranging in age from 21 to 81 yr and in physical-conditioning status (75-225 W maximum work load); rigorous screening excluded cardiac disease. Multiple regression analysis showed that the change in ESV (delta ESV) during a postural shift or during graded exercise was highly statistically correlated with the change in EDV (delta EDV) that occurred (r2 ranged from 0.34 to 0.49, correlation is positive) regardless of age, sex, or exercise work load. The correlation of delta ESV with delta EDV observed in this large sample, heterogeneous with respect to age, sex, and physical fitness, was also present in additional 31 subjects who exercised during beta-adrenergic blockade (propranolol 0.15 mg/kg). The delta EF with posture change and exercise in all subjects under all conditions was highly and inversely correlated with the delta ESV (r2 ranged from 0.38 to 0.81). Thus the delta ESV during the circulatory adaptive response to orthostatic and exercise stresses in humans is related to the delta EDV, and this relationship modulates the delta EF in response to these stresses.

Can serial exercise testing improve the prediction of coronary events in asymptomatic individuals?

An abnormal ST segment response to treadmill exercise has a low predictive value for future coronary events (angina pectoris, nonfatal myocardial infarction, or cardiac death) in apparently healthy individuals. To determine whether the conversion from a normal to an abnormal ST segment response might identify individuals at high risk for a future coronary event, we analyzed the results of serial exercise tests performed at 2-4-year intervals in 726 male and female volunteers, aged 22-84 years (mean, 55.1 years), from the Baltimore Longitudinal Study of Aging (BLSA). All subjects were free of cardiovascular disease at entry by history, physical examination, and resting 12-lead electrocardiogram. Over a mean overall follow-up of 7.4 years, coronary events occurred in 34 of 178 (19.1%) of those with an abnormal ST response to exercise versus 30 of 548 (5.5%) in those with a normal response (p = 0.001). Angina pectoris was the most common presenting coronary event regardless of ST segment exercise response. Among individuals with an abnormal ST segment response, the incidence of events was virtually identical between those with an initially abnormal response (group 1) and those who converted from a normal to an abnormal response (group 2), 19.8% versus 18.5%. After adjustment for standard coronary risk factors by proportional hazards regression analysis, the risk of a coronary event relative to subjects with persistently normal ST segment responses (group 3) remained nearly identical in the two groups, 2.72 in group 1 (p less than 0.003) and 2.80 in group 2 (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and long-term significance of exercise-induced frequent or repetitive ventricular ectopic beats in apparently healthy volunteers

Frequent or repetitive exercise-induced ventricular ectopic beats are often considered a marker for serious cardiac disease or sudden death, or both. However, the prognostic value of these arrhythmias in an unreferred asymptomatic community-dwelling population over a broad age range is unknown. Of 1,160 subjects aged 21 to 96 years who underwent maximal exercise treadmill testing an average of 2.4 times, 80 (6.9%) developed frequent (greater than or equal to 10% of beats in any 1 min) or repetitive (greater than or equal to 3 beats in a row) ventricular ectopic beats on at least one test. These 80 individuals were significantly older than the group without such arrhythmia (63.8 +/- 12.5 versus 50.0 +/- 16.1 years, p less than 0.0001). A striking age-related increase in the prevalence of frequent or repetitive exercise-induced ventricular ectopic beats was seen in men (p less than 0.0001) but not in women. The prevalence of electrocardiographic abnormalities at rest, exercise-induced ST segment depression and thallium perfusion defects, duration of treadmill exercise, maximal heart rate, systolic blood pressure and rate-pressure product did not differ between these 80 study subjects with frequent exercise-induced ventricular ectopic beats and a control group matched for age and gender. Furthermore, the incidence of cardiac events (angina pectoris, nonfatal myocardial infarction, cardiac syncope or cardiac death) (10% versus 12.5%) as well as noncardiac mortality (each 7.5%) was found to be similar for the study and control groups, respectively, over a mean follow-up period of 5.6 years. No study subjects required antiarrhythmic drugs over this time interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Physician utilization of laboratory procedures to monitor outpatients with congestive heart failure

Little is known about how different types of physicians use laboratory procedures in the management of outpatients with congestive heart failure. We therefore analyzed data from a national survey of randomly selected general practitioners, internists, and cardiologists to assess their management of outpatients with New York Heart Association class II congestive heart failure. Most of the 2704 respondents (90%) scheduled office visits between two and four months apart. Body weight, serum electrolytes, and chest roentgenograms were followed regularly by 98% or more of respondents, at median intervals of one to two months, three to five months, and 12 to 17 months, respectively. Serum digoxin levels in patients taking digoxin were followed by 90% of respondents at a median interval of 12 months. Echocardiography, radionuclide ventriculography, and exercise testing were used by fewer respondents (81%, 61%, and 61%, respectively), each at a median interval of 18 months or longer. Cardiologists were significantly more likely to follow patients using either echocardiography, radionuclide ventriculography, or exercise testing. The estimated yearly cost of following a class II congestive heart failure outpatient varied nearly fourfold from the lowest quartile of physicians ($303) to the highest ($1167). Cardiologists were disproportionately represented among the high-cost users. In addition, physicians who were younger or who practiced in an urban setting were significantly more likely to be high-cost users. Thus, simple laboratory tests were used most frequently to follow patients with heart failure, but differences in use of more expensive tests led to large differences in cost. Test use for similar patients is affected by characteristics of both the physician and practice setting.

Ventricular arrhythmias in the elderly: prevalence, mechanisms, and therapeutic implications

Aging is associated with an increase in both the prevalence and complexity of ventricular ectopic beats (VEB), whether detected by resting ECG, 24-hour ambulatory monitoring, or exercise testing. Frequent and/or multiform VEB, ventricular couplets, and short runs of ventricular tachycardia have been detected by these techniques in a sizeable percentage of apparently healthy subjects in the seventh decade and beyond. Although the mechanism for the increase in VEB with advancing age is uncertain, possibilities include latent coronary artery disease, left ventricular hypertrophy or dilatation, elevated plasma catecholamines, and a relative prolongation of the QT interval. Because the age-related increase in VEB does not appear to increase cardiac mortality in older subjects without demonstrable heart disease, and given the significant likelihood of adverse effects from antiarrhythmic drugs in their age group, these drugs should be reserved for elderly patients with organic heart disease and frequent or complex VEB.

Role of muscle loss in the age-associated reduction in VO2 max

A progressive decline in maximal O2 consumption (VO2max) expressed traditionally as per kilogram body weight generally occurs with advancing age. To investigate the extent to which this decline could be attributable to the age-associated loss of metabolically active tissue, i.e., muscle, we measured 24-h urinary creatinine excretion, an index of muscle mass, in 184 healthy nonobese volunteers, ages 22-87 yr, from the Baltimore Longitudinal Study of Aging who had achieved a true VO2max during graded treadmill exercise. A positive correlation was found between VO2max and creatinine excretion in both men (r = 0.64, P less than 0.001) and women (r = 0.47, P less than 0.001). As anticipated, VO2max showed a strong negative linear relationship with age in both men and women. Creatinine excretion also declined with age in men and women. When VO2max was normalized for creatinine excretion, the variance in the VO2max decline attributable to age declined from 60 to 14% in men and from 50 to 8% in women. Thus comparing the standard age regression of VO2max per kilogram body weight with that in which VO2max is normalized per milligram creatinine excretion, the decline in VO2max between a hypothetical 30 yr old and a 70 yr old was reduced from 39 to 18% in men and from 30 to 14% in women. We conclude that in both sexes, a large portion of the age-associated decline in VO2max in non-endurance-trained individuals is explicable by the loss of muscle mass, which is observed with advancing age.