Effects of 16 weeks of resistance training on left ventricular morphology and systolic function in healthy men >60 years of age

Resistance training (RT) has gained popularity as an effective form of exercise for older adults. However, the effects of RT on left ventricular (LV) morphology and systolic function in older persons is not well known. The purpose of this study was to assess the effects of 16 weeks of RT on LV morphology and systolic function in healthy older men. Subjects were randomly assigned into a RT group (n = 10; mean+/- SD age, 68 +/- 3 years) or a nonexercise control group (n = 10; age 68 +/- 4 years). RT was performed 3 times per week for 16 weeks at a mean intensity between 60% and 80% of 1 repetition maximum. Leg and bench press 1 repetition maximum and 2-dimensional echocardiography were performed at baseline and after 4, 8, 12, and 16 weeks of training in the RT group. Sixteen weeks of RT was associated with an increase in leg press maximal strength (baseline, 285 +/- 48 kg; after 16 weeks, 367 +/- 47 kg; p <0.05) and bench press maximal strength (baseline, 59 +/- 11 kg; after 16 weeks, 69 +/- 11 kg; p <0.05). No change in leg press maximal strength (baseline, 291 +/- 59 kg; after 16 weeks, 290 +/- 53 kg; p >0.05) or bench press maximal strength (baseline, 60 +/- 9 kg; after 16 weeks, 61 +/- 13 kg; p > .05) was found in control subjects during the same time. RT was not associated with changes in LV cavity size, wall thickness, mass, or systolic function after 4, 8, 12, and 16 weeks of exercise. Thus, 16 weeks of RT was sufficient to increase leg press and bench press maximal strength but did not alter the size or systolic function of the senescent left ventricle.

Acute Myocardial Infarction in Canada: New Epidemiologic Insights on Incidence, Therapy, and Risk

Objective: To define the changing incidence, risk, and therapy of acute myocardial infarction (A311). Data sources: Review of contemporary AMI data from the University of Alberta Hospitals, six other sites of the Clinical Quality Improvement Network (CQIN), and other Canadian and international centers. Data synthesis: Ischemic heart disease is age-related and the Canadian population is rapidly aging. At the University of Alberta Hospitals, the incidence of Q wave AMI (per 100,000 population) in 1985 was 113 and has remained unchanged (NS) since that time (129 in 1994). In contrast, the combined incidence of non.Q-wave AMI and unstable angina has increased markedly, from 74 in 1985 to 226 in 1994 (p < 0.05). The use of proven efficacious therapies for AMI has greatly increased in recent years, with thrombolytic drugs being given to approximately 35;percnt; of all patients by 1993; and beta-blockers and aspirin to 75;percnt; and 98;percnt; of patients, respectively. However, females and patients older than 70 years' despite their greater risk, received significantly less efficacious medication than males and younger AMI patients. The use of calcium antagonists decreased from a peak utilization rate of 60;percnt; for all AMI patients in 1989 to less than 10;percnt; by 1993. In-hospital AMI mortality risk has also decreased in the last several years, particularly among higher risk older patients (35;percnt;, 1987 vs. 19;percnt;,1993). In a population of 3896 consecutive AMI patients, recruited largely in 1992 and 1993 from seven CQIN sites, logistic regression analyses revealed aspirin was associated with the greatest relative risk reduction (61%); beta-blocker and thrombolytic therapy were related to risk reductions of 55;percnt; and 16;percnt;, respectively. Incremental age was the most important factor associated with increased relative risk in AMI, overall and in both sexes; sex was not an independent risk predictor. Qualitatively very similar AMI incidence, risk, and treatment data have also been recently observed in other centers in Canada, the United States, and elsewhere. Conclusions: Although widespread primary or secondary prevention is possibly contributory, the recent static incidence of Q-wave AMI and the marked increase in unstable angina and non-Q-wave AMI are more likely due to enhanced health awareness and diagnosis-seeking behavior in the population at risk. The decline in AMI mortality, at least for high-risk acute care patients, is compatible with a clinically relevant secondary prevention effect. There are still, however, windows of opportunity to further improve AMI outcomes by increasing the utilization of proven efficacious therapy, especially among women and older patients. Another particularly attractive epidemiologic benefit in the immediate future would accrue from the further development and effective use of efficacious therapies directed against unstable angina and n-Q-wave AMI.

The Canadian Study of Cardiac Transplantation. Atherosclerosis. Investigators of the CASCADE Study

OBJECTIVES

To describe risk factors associated with the development of transplantation coronary artery disease (TCAD).

DESIGN

A retrospective study of the Canadian experience.

PATIENTS

Seven hundred and nineteen patients with follow-up of at least 12 months following transplantation and a minimum of one coronary angiogram were analyzed.

RESULTS

Two hundred and fourteen patients (30%) developed angiographic evidence of TCAD during an average follow-up of 50+/-25 months. Actuarial freedom rate from TCAD averaged 60%, and survival averaged 85% five years following transplantation. Abnormal coronary angiograms increased from 11% to 40% between the first and the fifth year following transplantation. The Cox multivariate final model showed that recipients of donor hearts of 50 years and older (RR 4.35, 95% CI 2.32 to 8.15), patients with two or more episodes of acute rejection (RR 1.56, 95% CI 1.11 to 2.21) and patients with a diagnosis of ischemic cardiomyopathy before transplantation (RR 1.38, 95% CI 1.03 to 1.84) were at higher risk of TCAD. The same risk factors also had a significant effect on survival, although patients who were administered a hepatic hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor during follow-up had a higher survival rate (95% versus 85%, P=0.01) five years following heart transplantation.

CONCLUSIONS

Recipients of hearts from older donors, patients with an ischemic heart disease before transplantation and those with several episodes of acute rejection are at increased risk for TCAD. Patients who are administered an HMG-CoA reductase inhibitor during follow-up have a higher survival rate five years following transplantation.

The promise and practice of cardiovascular risk reduction: a disease management perspective. Clinical Quality Improvement Network (CQIN) Investigators

OBJECTIVE

Interpretive analysis of epidemiological, clinical trials and practice pattern data for cardiovascular risk reduction in the contemporary setting of unprecedented demographic changes.

DATA SOURCES

Literature review and audit results of the Clinical Quality Improvement Network (CQIN).

DATA SYNTHESIS

Coronary artery disease (CAD) is the largest single cause of death in Canada. CAD is age-related and the population is rapidly ageing, a combination that threatens an epidemic of future CAD events. Epidemiological data demonstrate a direct relation of CAD risk and serum cholesterol levels and no threshold cholesterol level below which there is no CAD risk. The epidemiological data also suggest CAD risk can be reduced by lowering serum cholesterol and this hypothesis has now been incontrovertibly confirmed by repeated randomized clinical trials. Most recently, reduction of all-cause mortality with cholesterol-lowering therapy in high risk subjects has also been confirmed. Despite the overwhelming trials and epidemiological evidence, CQIN effectiveness analyses reveal far from optimal risk assessment and management practices among high risk patients.

CONCLUSIONS

Serum cholesterol is directly related to CAD risk. Reduction of cholesterol reduces CAD, and all-cause, mortality in high risk patients. There is a large window of opportunity to improve lipid-lowering practices, and patient outcomes, for the most deadly diseases in our society.

Homologues of murine Vh11 gene are conserved during evolution

Since the murine Vh11 gene family shows 75% homology with group III VH gene families and is preferentially expressed in B-1 lymphocytes, we have analyzed if corresponding Vh11 genes existed across phylogenetically distant mammalian lineages. In a Southern blot, homologues of the murine Vh11 gene were detected in the genomic DNA from rats, pigs, sheep, cattle, horses, dogs and man. These observations suggest conservation of corresponding sequences of the Vh11 gene family during evolution, similar to group III VH genes, either because of strong selection pressures essential for species fitness and survival or molecular drive leading to these consequences.

Assessing appropriateness of treatment: a case study of transplantation in older patients with congestive heart failure

OBJECTIVE

To evaluate the appropriateness of transplantation therapy for older patients with congestive heart failure (CHF).

DATA SOURCES

Comparative review of contemporary survival and quality of life data of CHF patients treated medically versus by transplantation.

DATA SYNTHESIS

Approximately 300,000 Canadians have CHF and the incidence is increasing as the population ages; suitable donor allografts are found for about 300 CHF patients each year. Overall survival among cardiac allograft recipients, with a mean age of 48 years, is approximately 80% at two years. However, risk from all causes appears higher, and survival lower (range 40 to 78%), for transplant patients 55 years of age and older. Among medically treated patients, with mean age over 60 years, survival is inversely related to level of functional disability, averaging more than 90% at two years for patients with mild limitation and decreasing to 75% and 40% for patients with moderate and severe symptoms, respectively. Perceived quality of life is low in all CHF patients, but is significantly improved by intense out-patient care and education, irrespective of medical or transplant allocation.

CONCLUSIONS

Among adults with CHF, the greatest benefit of transplantation is enhanced survival in younger severely disabled patients. However, noncardiac risks are substantial, particularly for older recipients. The great discrepancy between donor and candidate availability prohibits transplantation from being a life expanding therapy for the whole CHF population. When physicians are, simultaneously, patients' and society's advocates a utilitarian decision model using the totality of efficacy data, including degree of efficacy and population effectiveness, may assist determination of the most appropriate therapy.

Patterns of practice in emergency department management of chest pain of suspected cardiac origin: clinical utility of single stat creatine kinase (CK)

The patterns of practice and the clinical utility of a single stat creatine kinase (CK) level in the emergency department management of chest pain of suspected cardiac origin were examined by a prospective observational study using a two-part questionnaire, completed by physicians before and after availability of CK results. The results showed that of the 776 patients in the study, 135 were admitted to hospital with acute myocardial infarction (AMI), 285 were admitted for reasons other than AMI, 343 were discharged, and 13 died or were transferred to another hospital. Although initial and final diagnoses in the emergency department did not differ in 597 patients (77%), initial decisions to admit or discharge were made in only 244 (31%) patients without waiting for CK results, and in 401 (52%) cases, decisions on patient disposition were deferred. Of 218 patients who had elevated CK levels, 193 (89%) were admitted, 121 for AMI. Only five (< 1%) patients who would otherwise have been discharged were admitted because of elevated CK levels. Of the 343 discharges, 245 (71%) occurred after the physicians knew the CK results. It is concluded that emergency department physicians routinely make changes in their diagnostic and management decisions based on current information and as it becomes updated. This study also suggests that there appears to be a heavy reliance on a single CK assay, although the relative importance of this diagnostic test compared to other factors is not known. Further studies are necessary.

Can practice patterns and outcomes be successfully altered? Examples from cardiovascular medicine. The Clinical Quality Improvement Network (CQIN) Investigators

OBJECTIVE

To offer an attributive opinion of recent improvements in acute myocardial infarction (AMI) practice patterns and patient outcomes in the culture of an active health care research program.

DATA SOURCES

Review of original clinical data from five sequential, consecutively enrolled, AMI patient cohorts at the University of Alberta Hospitals from 1987-93.

DATA SYNTHESIS

Early cohorts had low use of trial-proven efficacious therapies for AMI, particularly among high risk older and female patients. Over time, there were continuous and marked increases in the use of efficacious therapies and decreased use of nonefficacious therapies, with a parallel decrease in mortality among high risk patients.

CONCLUSIONS

In a large tertiary care hospital between 1987 and 1993 the use of evidence-based AMI therapy and survival in high risk patients significantly increased. The continuity and large size of these improvements in AMI practice patterns, compared with similar populations reported in the contemporary literature, suggest it is unlikely they were due to chance. Rather, intercurrent repeated measurement and reporting of key health care performance indicators, and initiation of explicit critical path AMI practice guidelines provide a more likely explanation. Future studies by a network of community and university investigators will test whether these findings are true for a broad AMI population and whether similar practice definition and improvement tools are effective for other cardiac problems, including the management of congestive heart failure.

Enhanced glucose oxidation in exercise-induced myocardial ischemia

BACKGROUND

In animal models, dichloroacetate (DCA) facilitates recovery from severe myocardial ischemia by stimulating glucose oxidation.

OBJECTIVE

To evaluate the acute efficacy of DCA as a metabolic anti-ischemic intervention in patients with coronary artery disease (CAD) and exercise-induced myocardial ischemia in a clinical trial.

METHODS

Double-blind, randomized, crossover comparison of single dose (50 mg/kg intravenously) DCA versus placebo on clinical and electrocardiographic variables in seven patients with single vessel CAD and 34 patients with multiple vessel CAD during standard dynamic exercise testing.

RESULTS

Blood pressure did not differ with placebo or DCA but mean heart rate was higher with DCA at rest (62 versus 59, P < 0.004) and at 5 mins of recovery (78 versus 75, P < 0.02). Exercise duration averaged 538 s with DCA and 534 s with placebo (not significant). Chest pain occurred in 14 patients in both tests, clinical ST depression occurred, in 34 placebo tests and 37 DCA tests (not significant). Body surface potential maps (BSPM) of the decrease in the area under the ST curve from rest to peak exercise averaged -5096 microV's with DCA and -5159 microV's with placebo (not significant). BSPM at 1 and 5 mins postexercise also showed no differences in rate of ST integral recovery.

CONCLUSIONS

In the transient regional model of human myocardial ischemia induced by dynamic exercise, the acute administration of the pyruvate dehydrogenase agonist DCA was not associated with clinical or electrocardiographic moderation of, nor accelerated recovery from, ischemia. Whether DCA or metabolically similar agents that enhance oxidative metabolism are beneficial in other ischemic settings, such as the no-flow states of acute ST elevation myocardial infarction or angioplasty, requires further systematic evaluation.

Prevention and regression of coronary atherosclerosis. Is it safe and efficacious therapy?

OBJECTIVE

Atherosclerotic coronary heart disease (CHD) continues to be the dominant disease in Western society. A large body of evidence directly linking serum cholesterol levels and CHD risk has stimulated population treatment strategies designed to reduce cholesterol and CHD risk. Data indicating a relation between low cholesterol and non-CHD risk have, however, suggested that cholesterol reduction may not always be desirable. The primary goal of this evaluative review of the available evidence was to answer the following question: Is prevention/regression therapy for CHD safe and effective?

DATA SOURCES

Three lines of evidence were reviewed: epidemiologic studies; primary and secondary prevention trials with clinical end points; and secondary prevention trials with quantitative coronary angiography as a surrogate end point for clinical CHD.

STUDY SELECTION

Original studies and meta-analyses were reviewed. The principal selection criteria for the epidemiologic studies were large size and prolonged follow-up; for the trials, randomization and viable clinical (CHD events, CHD mortality, total mortality) or angiographic end points.

DATA EXTRACTION

The data were initially extracted by a single reviewer using common qualitative guidelines. The data were then evaluated by all authors acting as a data interpretation team.

DATA SYNTHESIS

Overall, the epidemiologic data revealed excess risk of fatal and nonfatal CHD events was directly related to total cholesterol and low-density lipoprotein (LDL) cholesterol levels, for both men and women and for both younger (< 65 years) and older (> or = 65 years) patients, over a wide range of serum cholesterol levels. The predictive value was higher in younger men than older men and women, although part of this quantitative interaction may be due to fewer studies, with fewer end points, in the older and female populations. The CHD events and CHD mortality, but not total mortality, were consistently reduced in trials of cholesterol-lowering therapy. The regression trials, predominantly in CHD patients with high cholesterol values (mean 7.1 mmol/L), demonstrated improvement in angiographic atherosclerosis in every study. The evidence for elevated risk of non-CHD death at very low levels of cholesterol is uncertain and controversial. The most likely possibilities for this apparent relationship are unknown confounding variables and the play of chance.

CONCLUSIONS

Serum cholesterol levels are directly associated with CHD risk, and there is no threshold level below which there is no risk. Reduction of high serum cholesterol levels reduces CHD risk. Whether lipid-lowering and adjunctive antiatherosclerotic therapies are effective and safe in the majority of CHD patients who have desirable or borderline cholesterol levels remains undetermined.

Skeletal muscle metabolism in the chronic fatigue syndrome. In vivo assessment by 31P nuclear magnetic resonance spectroscopy

BACKGROUND

Previous study of patients with chronic fatigue syndrome (CFS) has demonstrated a markedly reduced dynamic exercise capacity, not limited by cardiac performance and in the absence of clinical neuromuscular dysfunction, suggesting the possibility of a subclinical defect of skeletal muscle.

METHODS

The in vivo metabolism of the gastrocnemius muscles of 22 CFS patients and 21 normal control subjects was compared during rest, graded dynamic exercise to exhaustion and recovery, using 31P nuclear magnetic resonance (NMR) spectroscopy to reflect minute-to-minute intracellular high-energy phosphate metabolism.

RESULTS

Duration of exercise was markedly shorter in the CFS patients (8.1 +/- 2.8 min) compared with the normal subjects (11.3 +/- 4.3 min) (p = 0.005). There were large changes in phosphocreatine (PCr), inorganic phosphate (Pi), and pH from rest to clinical fatigue in all subjects, reflecting the high intensity of the exercise. The temporal metabolic patterns were qualitatively similar in the CFS patients and normal subjects. There were early and continuous changes in PCr and Pi that peaked at the point of fatigue and rapidly reversed after exercise. In contrast, pH was relatively static in early exercise, not declining noticeably until 50 percent of total exercise duration was achieved, and reaching a nadir at 2 min postexercise, before rapidly reversing. There were no differences in pH at rest (7.08 +/- 0.04 vs 7.10 +/- 0.04), exhaustion (6.85 +/- 0.17 vs 6.76 +/- 0.17) or early (6.64 +/- 0.25 vs 6.56 +/- 0.24) or late recovery (7.09 +/- 0.04 vs 7.10 +/- 0.05), CFS patients vs normal subjects, respectively (NS). Neither were there intergroup differences (NS) in PCr or Pi. Although, quantitatively, the changes in PCr, Pi, and pH were marked and similar in both groups from rest to exhaustion, the changes all occurred much more rapidly in the CFS patients. Moreover, adenosine triphosphate (ATP) was significantly (p = 0.007) less at exhaustion in the CFS group.

CONCLUSIONS

Patients with CFS and normal control subjects have similar skeletal muscle metabolic patterns during dynamic exercise and reach similar clinical and metabolic end points. However, CFS patients reach exhaustion much more rapidly than normal subjects, at which point they also have relatively reduced intracellular concentrations of ATP. These data suggest a defect of oxidative metabolism with a resultant acceleration of glycolysis in the working skeletal muscles of CFS patients. This metabolic defect may contribute to the reduced physical endurance of CFS patients. Its etiology is unknown. Whether CFS patients' overwhelming tiredness at rest has a similar metabolic pathophysiology or etiology also remains unknown.

In vivo skeletal muscle metabolism during dynamic exercise and recovery: assessment by nuclear magnetic resonance spectroscopy

BACKGROUND

The purpose of this study was to define temporally phosphorus metabolism and pH in the gastrocnemius muscles of 21 normal adult subjects during rest, dynamic exercise to exhaustion, and early and late recovery.

METHODS

In vivo nuclear magnetic resonance spectroscopy.

RESULTS

At rest, the ratio of phosphocreatine to the alpha peak of ATP averaged 2.26 +/- 0.25, the inorganic phosphate to ATP ratio averaged 0.31 +/- 0.08 and pH averaged 7.10 +/- 0.04. The phosphorus metabolites exhibited immediate and progressive changes with exercise, reaching their minimum (phosphocreatine, 0.95 +/- 0.41) or maximum (inorganic phosphate, 1.95 +/- 0.75) values at exhaustion, after an average exercise of 11 +/- 4 mins. In contrast, pH changed slowly during early exercise, but fell abruptly thereafter and averaged 6.76 +/- 0.17 at exhaustion. Phosphocreatine and inorganic phosphate began to return rapidly towards preexercise values immediately on cessation of exercise. However, pH declined further in the period immediately following cessation of exercise, reaching a nadir of 6.56 +/- 0.24 an average of 2 mins into recovery. Exercise duration did not correlate highly with any metabolic variable.

CONCLUSIONS

The data support the concept that the metabolic physiology underlying physical exhaustion of dynamic exercising muscle is multifactorial. The post exercise drop in pH also suggests that normal subjects have a greater contribution to high energy phosphate production from glycolysis, as opposed to oxidative metabolism, in early recovery.

Acute myocardial infarction: contemporary risk and management in older versus younger patients

The in-hospital management and risk of death of 101 patients 70 years of age or older with acute myocardial infarction in 1987 (group 1) were compared with management and risk for 106 temporally matched patients less than 70 years old (group 2). In group 1, 49% had histories of previous myocardial infarction, compared to 25% in group 2 (P less than 0.001), and 23% of group 1 presented without cardiac pain, versus 7% of group 2 (P less than 0.001). Among the younger patients, other conventional risk factors were, in contrast, more common (Q wave infarction 84% in group 2 versus 70% in group 1; P less than 0.05) or higher (peak creatine kinase values 2222 iu/L in group 2 versus 1366 iu/L in group 1; P less than 0.001). Prior to infarction, all cardiac drugs were used more frequently in the older group 1 patients, whereas post infarction thrombolysis, beta-blockers and acetylsalicylic acid use were all more common (P less than 0.01 to P less than 0.001) in the younger group 2 patients. Post infarction exercise testing, left ventricular ejection fraction calculations and coronary angiography were all performed less frequently in group 1 (P less than 0.001). The in-hospital mortality was 35% for group 1 versus 7% for group 2 (P less than 0.001). Among all 207 study subjects, multiple logistic regression revealed thrombolysis, absence of cardiac pain, and age 70 years or older to be associated with the greatest relative mortality risk. Increased relative risk to a lesser degree was associated with previous infarction, male sex and post infarction use of antiarrhythmic medication.(ABSTRACT TRUNCATED AT 250 WORDS)