Maximal Treadmill Stress Test Research Articles

Euterpe oleracea Mart. (Açai) seed extract improves physical performance in old rats by restoring vascular function and oxidative status and activating mitochondrial muscle biogenesis.

Alterations in cardiovascular and skeletal muscle function are hallmarks of ageing that lead to exercise intolerance. We aimed to examine whether the treatment with Euterpe oleracea Mart. seed extract (ASE) associated with exercise training improves aerobic exercise performance by promoting healthy ageing in the elderly. Male Wistar rats were divided into five groups: Young (3 months), Old (18 months), Old+ASE (ASE 200 mg/kg/day), Old+Training (exercise training 30 min/day; 5 days/week) and Old+Training+ASE, for 4 weeks. ASE treatment increased the exercise time and the running distance concerning the initial maximal treadmill stress test (MTST) in the Old+Training+ASE group. Exercise training or ASE treatment restored the aorta oxidative damage and antioxidant defence. It reduced the acetylcholine (ACh)-induced vasodilation in the aorta of old animals to the same values as the young and improved hypertension. Only the association of both strategies restored the ACh-induced vasodilation in mesentery arteries. Remarkably, exercise training associated with ASE increased the antioxidant defence, nitrite levels and expression of the mitochondrial SIRT-1, PGC1α in soleus muscle homogenates. ASE treatment associated with exercise training contributes to better exercise performance and tolerance in ageing by improving vascular function, oxidative stress and activating the muscle SIRT-1/PGC-1α pathway.

Exercise increases arterial stiffness independent of blood pressure in older Veterans.

Exercise-induced changes in arterial function could contribute to a hypertensive response to exercise (HRE) in older individuals. We performed the present analysis to define the acute arterial stiffness response to exercise in ambulatory older adults. Thirty-nine Veterans (>60 years old), without known cardiovascular disease, participated in this study, including 19 Veterans who were hypertensive (70.8 ± 6.8 years, 53% women) and 20 Veterans who were normotensive (72.0 ± 9.3 years, 40% women). Arterial stiffness parameters were measured locally with carotid artery ultrasound and regionally with carotid-femoral pulse wave velocity (cfPWV) before and during the 10 min after participants performed a Balke maximal exercise treadmill stress test. The arterial stiffness response to exercise was similar for control and hypertensive participants. At 6 min postexercise, cfPWV was significantly increased (Δ1.5 ± 1.9 m/s, P = 0.004) despite mean blood pressure (BP) having returned to its baseline value (Δ1 ± 8 mmHg, P = 0.79). Arterial mechanics modeling also showed BP-independent increases in arterial stiffness with exercise ( P < 0.05). Postexercise cfPWV was correlated with postexercise SBP ( r = 0.50, P = 0.004) while baseline cfPWV ( r = 0.13, P = 1.00), and postexercise total peripheral resistance ( r = -0.18, P = 1.00) were not. In older Veterans, exercise increases arterial stiffness independently of BP and the arterial stiffness increase with exercise is associated with increased postexercise SBP. BP-independent increases in arterial stiffness with exercise could contribute to a HRE in older adults.

Açaí (Euterpe oleracea Mart.) seed extract improves aerobic exercise performance in rats

The purpose of this study was to examine whether the supplementation with an açai (Euterpe oleracea Mart.) seed extract (ASE) would affect the aerobic exercise performance in rats and correlate with the vascular function, muscle oxidative stress and mitochondrial biogenesis. Male Wistar rats were divided into five groups: Sedentary, Sedentary with chronic supplementation of ASE, Training, Training with chronic (200 mg/Kg/day intragastric gavage for 5 weeks) or acute (30 min before the maximal treadmill stress test (MST) supplementation with ASE. The exercise training was performed on a treadmill (30 min/day; 5 days/week) for 4 weeks. The chronic supplementation with ASE increased the exercise time (58%) and the running distance (129%) in relation to the MST, while the Training group increased 40% and 78% and the Training with acute ASE group increased 30% and 63%, respectively. The training-induced increase of ACh vasodilation was not changed by ASE, but the norepinephrine-induced vasoconstriction was reduced by chronic and acute supplementation with ASE. The increased levels of malondialdehyde in soleus muscle homogenates from the Training group was reduced only by chronic supplementation with ASE. The muscle antioxidant defense, NO2 levels, and expression of the mitochondrial biogenesis-related proteins (PGC1α, SIRT-1, p-AMPK/AMPK, Nrf-2) were not different between Training and Sedentary groups, but all these parameters were increased in the Training with Chronic ASE compared with the Sedentary groups. In conclusion, chronic supplementation with ASE improves aerobic physical performance by increasing the vascular function, reducing the oxidative stress, and up-regulating the mitochondrial biogenesis key proteins.

Effects of clipping endoscopic thoracal sympathectomy at Th4 on cardiopulmonary functions, quality of life and psychosocial functions

In this study, we evaluated the cardiopulmonary and psychosocial effects of endoscopic thoracal sympathectomy (ETS) by clipping procedure at the level of Th4 and effects of ETS on quality of life of patients with hyperhidrosis. We performed a prospective study in 52 patients complaining of local sweating who applied to our clinic. Cardiac maximal treadmill stress test (CMTST), pulmonary function tests, Beck anxiety-depression inventory, Liebowitz social anxiety scale and SF-36 quality of life questionnaires were administered at preoperative period and postoperative 6th month. In the pulmonary function test, we found a minimal decrease in FEV1, and FEV1/FVC. There were no significant change in 'resting pulse rate', 'resting systolic and diastolic blood pressures' during CMTST between before and after operation. There was a significant difference in peak heart rate before CMTST, post-exercise diastolic blood pressure, and age-predictive maximal heart rate between before and after clipping procedure. In the SF-36 questionnaire, all parameters were improved. In the Beck depression-anxiety inventory and the Liebowitz social anxiety scale significant improvement was achieved in all parameters. ETS by clipping procedure at the Th4 level is advised to be a safe and effective method for management of hyperhidrosis patients.

Caffeine prevents exercise-induced hypoglycemia in trained runners

The objective of this study was to analyze the physiological, biochemical, and perceptive effects of caffeine intake in marathon runners after a maximal treadmill stress test. The sample comprised randomly selected 12 male athletes of long distance races (42,125 km). The participants performed the maximal stress test twice, after ingesting a placebo and caffeine (dose de 6 mg.kg-1) capsules, using double-blind methodology. Anthropometric parameters, heart rate (HR), blood pressure (BP), and subjective perception of effort (SPE) were evaluated before, during, and after the test. Blood samples for analyses of glucose, lactate (LAC), and triglyceride (TG) levels were also collected at the same time. The maximal stress test was performed on a treadmill, and parameters such as VO2 max and subjective perception of effort (SPE) were analyzed. Before the trial and caffeine/placebo ingestion, capillary blood was collected by finger puncture for subsequent analyses. Subsequently, the maximal treadmill stress test was initiated with a 3-minute low intensity warm-up phase. The trial continued with the maximal treadmill stress test protocol, followed by a cool-down period (walk) until HR normalization. The athletes remained seated for 10 minutes, and during this period, HR and BP were measured, and blood samples were collected. HR values presented no difference between groups. However, glucose, TG, and LAC levels different after caffeine intake. The results of the present study demonstrated that caffeine ingestion modifies glucose, TG, and LAC availability during exercise in trained runners.

Exercise Capacity and the Obesity Paradox in Heart Failure: The FIT (Henry Ford Exercise Testing) Project

ObjectivesTo assess the influence of exercise capacity and body mass index (BMI) on 10-year mortality in patients with heart failure (HF) and to synthesize these results with those of previous studies. Patients and MethodsThis large biracial sample included 774 men and women (mean age, 60±13 years; 372 [48%] black) with a baseline diagnosis of HF from the Henry Ford Exercise Testing (FIT) Project. All patients completed a symptom-limited maximal treadmill stress test from January 1, 1991, through May 31, 2009. Patients were grouped by World Health Organization BMI categories for Kaplan-Meier survival analyses and stratified by exercise capacity (<4 and ≥4 metabolic equivalents [METs] of task). Associations of BMI and exercise capacity with all-cause mortality were assessed using multivariable-adjusted Cox proportional hazards models. ResultsDuring a mean follow-up of 10.1±4.6 years, 380 patients (49%) died. Kaplan-Meier survival plots revealed a significant positive association between BMI category and survival for exercise capacity less than 4 METs (log-rank, P=.05), but not greater than or equal to 4 METs (P=.76). In the multivariable-adjusted models, exercise capacity (per 1 MET) was inversely associated, but BMI was not associated, with all-cause mortality (hazard ratio, 0.89; 95% CI, 0.85-0.94; P<.001 and hazard ratio, 0.99; 95% CI, 0.97-1.01; P=.16, respectively). ConclusionMaximal exercise capacity modified the relationship between BMI and long-term survival in patients with HF, upholding the presence of an exercise capacity-obesity paradox dichotomy as observed over the short-term in previous studies.

EFEITO DO ESFORÇO FÍSICO NO DESEMPENHO DE TIRO DE POLICIAIS MILITARES DO BATALHÃO DE CHOQUE

RESUMO Introdução: O uso de arma de fogo por policiais militares normalmente é precedido por perseguição a pé, e as alterações fisiológicas produzidas pelo esforço físico podem afetar o desempenho do tiro. Objetivo: Verificar o efeito do esforço físico sobre o desempenho de tiro em policiais militares. Métodos: A amostra foi constituída por 15 homens (34,1 ± 5,4 anos; 81,4 ± 8,8 kg; 171,3 ± 5,6 cm; 27,7 ± 2,3 kg/m²; 44,9 ± 4,0 ml.kg-1.min-1) do batalhão de choque da polícia militar. Na primeira sessão, os participantes realizaram um teste de esforço máximo em esteira no qual se mediu o consumo pico de oxigênio (VO2pico). Na segunda sessão, foi avaliado o desempenho (pontuação) e tempo de tiro pré e pós-esforço físico e o tempo gasto no circuito de corrida com obstáculos (297 m). O índice de eficiência de tiro foi calculado pela razão entre a pontuação total e tempo de execução de tiro. O teste de Shapiro-Wilk confirmou a normalidade da distribuição dos dados. Utilizou-se o teste t pareado para comparação das variáveis desfecho pré e pós-esforço e o coeficiente de correlação de Pearson. Resultados: O tempo para completar o percurso de corrida foi 75,3 ± 4,4 s. O desempenho (20,4 ± 11,4 vs. 17,6 ± 9,3 pontos), tempo (4,48 ± 1,1 vs. 4,23 ± 0,9 s) e eficiência de tiro (4,69 ± 2,7 vs. 4,35 ± 2,7 pts./s) não apresentaram diferenças significativas (P &gt; 0,2). Além disso, detectou-se uma correlação entre o VO2pico e o tempo de execução da corrida (r = -0,64; P = 0,01), mas não com o desempenho de tiro (P &gt; 0,05). Conclusão: O esforço físico não afeta o desempenho de tiro de policiais militares. Apesar de o nível de aptidão aeróbica não ser associado ao desempenho de tiro, foi associado ao desempenho físico realizado previamente aos disparos.

Fitness, Fatness, and Mortality: The FIT (Henry Ford Exercise Testing) Project

BackgroundThe combined influence of fitness and fatness on mortality risk in diverse populations has not been adequately explored. Our aim was to assess the relative impact of exercise capacity and body mass index (BMI) on all-cause mortality. MethodsWe included 29,257 men and women (mean age 53 years; 27% African American) from The Henry Ford Exercise Testing (FIT) Project without cardiovascular disease and diabetes mellitus at baseline. All patients completed a symptom-limited maximal treadmill stress test between 1991 and 2009. Patients were grouped for analysis by exercise capacity (≥10 metabolic equivalents of task [METs] and <10 METs) and obesity status (≥30 kg/m2 and <30 kg/m2), forming 4 subgroups. Independent and joint associations of BMI and exercise capacity with all-cause mortality were assessed using Cox proportional hazard models. ResultsDuring a mean follow-up of 10.8 years, 1898 patients (6.5%) died. We observed a strong inverse association between exercise capacity (per 1 MET unit) and all-cause mortality (hazard ratio [95% confidence interval], 0.86 [0.85-0.88]). Body mass index (per 1 BMI unit) was inversely related to mortality (hazard ratio [95% confidence interval], 0.98 [0.97-0.99]). In joint analysis, the highest mortality risk was in the <10 METs/<30 kg/m2 subgroup. ConclusionsReduced exercise capacity was a strong independent risk factor for all-cause mortality in this racially diverse population. Given the comparatively limited impact of BMI, more emphasis should be placed on measuring exercise capacity and developing strategies for its improvement in cardiovascular disease prevention programs.

Relation Between Self-Reported Physical Activity Level, Fitness, and Cardiometabolic Risk

Physical activity and cardiorespiratory fitness are associated with improved cardiovascular health and reduced all-cause mortality. The relation between self-reported physical activity, objective physical fitness, and the association of each with cardiometabolic risk has not been fully described. We studied 2,800 healthy Brazilian subjects referred for an employer-sponsored health screening. Physical activity level was determined as "low," "moderate," or "high" with the International Physical Activity Questionnaire: Short Form (IPAQ-SF). Fitness was measured as METs achieved on a maximal, symptom-limited, treadmill stress test. Using multivariate linear regression analysis, we calculated age, gender, and smoking-adjusted correlation coefficients among IPAQ-SF, fitness, and cardiometabolic risk factors. Mean age of study participants was 43 ± 9 years; 81% were men, and 43% were highly active. Mean METs achieved was 12 ± 2. IPAQ-SF category and fitness were moderately correlated (r = 0.377). Compared with IPAQ-SF category, fitness was better correlated with cardiometabolic risk factors including anthropomorphic measurements, blood pressure, fasting blood glucose, dyslipidemia, high-sensitivity C-reactive protein, and hepatic steatosis (all p <0.01). Among these, anthropomorphic measurements, blood pressure, high-sensitivity C-reactive protein, and hepatic steatosis had the largest discrepancies in correlation, whereas lipid factors had the least discrepant correlation. When IPAQ-SF and fitness were discordant, poor fitness drove associations with elevated cardiometabolic risk. In conclusion, self-reported physical activity level and directly measured fitness are moderately correlated, and the latter is more strongly associated with a protective cardiovascular risk profile.

Non-invasive coronary angiography for patients with acute atypical chest pain discharged after negative screening including maximal negative treadmill stress test. A prospective study

Among patients admitted in the emergency department for acute atypical chest pain those with an acute coronary syndrome (ACS) who are mistakenly discharged home have high mortality. A recent retrospective study has demonstrated that multislice computed tomography (MSCT) coronary angiography could improve triage of these patients. We aimed to prospectively confirm these data on patients with a negative screening including maximal treadmill stress. Patients 30 patients discharged from the emergency department after negative screening for an ACS were included. All patients underwent MSCT angiography of the coronary artery. Patients with coronary atheroma on MSCT had an invasive coronary angiography to confirm these findings. Results Seven patients (23%) had obstructive coronary artery disease on MSCT. Invasive coronary angiography (ICA) confirmed the diagnosis in all patients. Conclusion In patients with no previously known coronary artery disease admitted to the emergency department with atypical acute chest pain and discharged after negative screening, including maximal treadmill stress test, MSCT coronary angiography is useful for the diagnosis of obstructive coronary artery disease.

Metabolic Syndrome Status Changes with Fitness Level Change: A Retrospective Analysis

Cardiorespiratory fitness level is inversely related to the incidence of Metabolic Syndrome (MetS). This study examined the effects of changes in cardiorespiratory fitness level on MetS status. Male and female participants in a health enhancement program (n = 212) were clinically examined for changes in their MetS status and estimated aerobic capacity over a 3-year period. Two physical examinations, each including a maximal treadmill stress test, occurred within this time frame. Participants were divided into three groups: Group 1 (n = 103) was composed of individuals who presented with MetS at exam 1 and reversed their MetS disease status by exam 2; Group 2 (n = 75) members presented with MetS at both exams; and Group 3 (n = 34) individuals were MetS-free at exam 1 but acquired MetS by exam 2. The relationships between MetS clinical characteristics at exam 1 and exam 2 and changes in graded exercise test (GXT) duration were contrasted for the three groups. GXT duration, estimated aerobic capacity (VO(2) max), and MetS characteristics improved significantly in Group 1 (P < 0.01). Group 2 individuals also increased GXT duration (P < 0.05) but showed only nonsignificant improvements (P > 0.05) in clinical characteristics. Group 3 members declined in most MetS characteristics and in estimated VO(2) max (P < 0.05). Increases in GXT duration accompanied MetS reversal while declines in GXT duration occurred with MetS acquisition. On an individual basis, these changes in GXT duration may be an indicator of disease status.

Heart Rate and Blood Pressure Response in Adult Men and Women During Exercise and Sexual Activity

The purpose of this study was to assess the heart rate (HR) and blood pressure (BP) response of sexual activity compared with treadmill exercise in adult men and women. Nineteen men, 55 +/- 8 years, and 13 women, 51 +/- 7 years, underwent a maximal Bruce protocol treadmill stress test followed by home-monitored sexual activity using noninvasive HR and BP recording devices. The mean treadmill times were significantly shorter than the mean times of sexual activity for men and women (p <0.001 and p = 0.002, respectively). For the men, average maximum HR, systolic BP, and HR-BP product during sexual activity were 72%, 80%, and 57% of respective measurements during treadmill exercise. For the women, maximum HR, systolic BP, and HR-BP product during sexual activity were 64%, 75%, and 48% of respective measurements during treadmill exercise. Age correlated inversely with duration of treadmill exercise (a 9-second decrease in duration per increasing year of age; p = 0.036), and with the duration of sexual activity (a 1-minute decrease in duration per increasing year of age; p = 0.024). Treadmill exercise duration predicted sexual activity duration (a 2.3-minute increase in sexual activity duration per each minute treadmill duration; p = 0.026). In conclusion, sexual activity provides modest physical stress comparable with stage II of the standard multistage Bruce treadmill protocol for men and stage I for women.

Relation between C-reactive protein, treadmill exercise testing, and inducible myocardial ischemia

This study examined the relation between high-sensitivity C-reactive protein (CRP), exercise-induced myocardial ischemia, and exercise tolerance in 288 stable patients who underwent maximal treadmill stress testing. CRP was correlated with peak exercise workload, which was consistent with the long-term predictive value of peak workload and CRP for outcome events. There was no correlation of high-sensitivity CRP with stress-induced ischemia, which is consistent with a lack of correlation between CRP and the degree of chronic luminal coronary arterial narrowing.

Coagulation and fibrinolytic responses to manual versus automated snow removal.

The purpose of this study was to assess coagulation and fibrinolytic responses to snow removal. Thirteen healthy male subjects (age = 26 +/- 5 yr, height = 179.0 +/- 7.0 cm, weight = 78.7 +/- 16.1 kg, .VO2max = 54.7 +/- 8.9 mL.kg-1.min-1) underwent maximal treadmill stress testing (TM), 10 min of snow shoveling (SS), and 10 min of snow removal using an automated snow thrower (ST). Blood was collected immediately before and after each test and analyzed for von Willebrand Factor antigen (vWF:ag), tissue plasminogen activator (tPA) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a two-factor repeated-measures analysis of variance. vWF:ag significantly increased during TM (84.7 +/- 21.7% normal preexercise, 149.0 +/- 45.6% normal postexercise) but not SS or ST. TM resulted in significant increases in tPA antigen (6.54 +/- 2.76 ng.mL-1 preexercise, 21.39 +/- 10.56 ng.mL-1 postexercise) and both SS and TM caused significant reductions in PAI-1 activity (SS = 15.1 +/- 3.8 AU.mL-1 preexercise, 13.2 +/- 4.3 AU.mL-1 postexercise; TM = 15.3 +/- 3.6 AU.mL-1 preexercise, 10.5 +/- 5.3 AU.mL-1 postexercise). Postexercise PAI-1 activity was significantly lower for TM versus SS. tPA antigen was unchanged after SS and ST, and PAI-1 activity was unchanged after ST. vWF:ag is unchanged after self-paced snow shoveling and automated snow removal in young, healthy males. Snow shoveling acutely increases fibrinolytic potential in this population, although not to the degree observed after maximal treadmill exercise.

Effect of acute exhausting exercise on cytokine gene expression in men.

Because of recent interest in the effects of physical exercise on immunologic function, we decided to use state-of-the-art methods to evaluate cytokines in the peripheral blood leukocytes (PBLs) of 7 men before and after a maximal treadmill stress test. Change in cytokine gene expression was quantified from PBLs using a reverse transcriptase polymerase chain reaction assay (RT-PCR). In contrast to reports on serum levels or using in vitro testing, direct gene expression of TNF-alpha decreased after the stress test (p < 0.008). However, the 47% decrease was relatively small and of questionable biological significance. Levels of IL-1a, IL-1b, IL-2, IL-4, IL-6, IL-10, and INF-gamma did not change.

Exercise technetium-99m sestamibi tomography for cardiac risk stratification of patients with stable chest pain.

This study was designed to evaluate the prognostic value of symptom-limited maximal exercise treadmill testing with tomographic technetium-99m sestamibi (MIBI) myocardial imaging in patients referred for evaluation of stable angina. Exercise stress thallium-201 myocardial imaging provides prognostic information in coronary artery disease subsets including patients with stable chest pain. The prognostic value of exercise technetium-99m MIBI myocardial tomography has not been established. Of 548 consecutive patients with stable angina pectoris who underwent maximal exercise treadmill stress testing in combination with a same-day "rest-stress" tomographic technetium-99m MIBI myocardial imaging protocol, 521 patients were followed for 13 +/- 5 months to determine the univariate and multivariate variables associated with cardiac events and to define their cardiac event-free survival. Ten patients were lost to follow-up (98% complete), and 17 who had coronary revascularization within 6 months of testing were excluded. Major cardiac events occurred in 24 patients (9%)--nonfatal myocardial infarction in 11 and cardiac death in 13. Univariate Cox survival analysis demonstrated significant relative risk (RR) and 95% confidence intervals (CI) for exercise ST segment depression (RR = 2.3; 95% CI, 1.0 to 5.3), an abnormal MIBI scan (RR = 13.8; 95% CI, 1.9 to 102.3), and a reversible MIBI perfusion defect (RR = 3.2; 95% CI, 1.4 to 7.5). Multivariate models demonstrated that both exercise MIBI perfusion abnormalities (RR = 11.9; 95% CI, 1.6 to 89.4) and reversible MIBI perfusion defects (RR = 2.9; 95% CI, 1.2 to 7.0) had independent predictive value. During 1 year of follow-up, cardiac events occurred in only 0.5% of patients with normal MIBI scans compared with 7% of those with abnormal MIBI scans (P < .001). One-year, cardiac event-free survival was 92% in patients with reversible MIBI perfusion defects (P < .01 versus normal), 96% in patients with fixed defects (P < .01), and 93% in patients with combined reversible and fixed MIBI myocardial perfusion abnormalities (P < .02). As with exercise thallium-201 myocardial imaging, exercise stress technetium-99m MIBI myocardial tomography provides significant independent information concerning the subsequent risk of serious cardiac events (death, myocardial infarction) in patients with stable angina pectoris. The identification of MIBI perfusion abnormalities, in particular, the presence of reversible MIBI defects, was associated with reduced 1-year, event-free survival. The recognized imaging and radiotracer biokinetic differences between thallium-201 and MIBI do not appear to modulate the prognostic value associated with scintigraphic evidence of ischemic myocardial jeopardy in the stable angina population.

An Analysis of the Validity of the Three-Mile Run as a Field Test of Aerobic Capacity in College Males

The purpose of the present investigation was to examine the concurrent and construct validity of the three-mile (4.83 km) run as a field test of aerobic capacity. Subjects included 109 college-aged males whose three-mile run time (M = 1310.31 +/- 184.48 s) was measured. Fifty of the subjects were given a maximal treadmill stress test, and their peak oxygen consumption (VO2peak) (M = 54.23 +/- 7.08 ml.kg-1.min-1) was measured. The three-mile run was conducted on an outdoor 0.25 mile (0.425 km) track, and split times were recorded each 110 yds (100.32 m) for the first and last laps and total time was recorded for laps 2 through 11. The correlation coefficient between the run time and VO2peak was -.58, indicating only moderate concurrent validity for the run as a field test for aerobic capacity. A factor analysis conducted on the split time data revealed a three-factor structure of a stable pace phase, an initial sprint, and a final sprint with the stable pace factor accounting for most of the common factor variance (69%). The three-mile run time was used to discriminate successfully between two known groups of subjects in aerobic capacity. These data provide a degree of support for the construct validity of the three-mile run as a field test of aerobic capacity.

Significance of blood taurine levels in patients with first time acute ischaemic cardiac pain

We studied blood taurine levels of 91 consecutive patients admitted with first time cardiac pain suggestive of myocardial ischaemia. Blood taurine levels of patients with coronary arterial disease, but without a recent myocardial infarction ( n = 36), at rest and after a maximal treadmill stress testing were also determined. The blood taurine level at the time of admission was significantly elevated ( P < 0.001) in patients with an acute myocardial infarction ( n = 63) (271 ± 98 μmol/l) and those with unstable angina ( n = 22) [214 ± 81 μmol/l] compared to that of normal subjects ( n = 75) at rest (140 ± 40 μmol/l). Patients with a myocardial infarction had a higher level than those with unstable angina ( P < 0.01) and non-ischaemic chest pain ( n = 6) [ P < 0.05]. The levels peaked after 12–48 hours only in patients with infarction [367 ± 140 μmol/l] ( P < 0.001) and unstable angina (273 ± 82 μmol/l) ( P < 0.02). The levels of creatine kinase within the serum at the time of admission did not correlate well with those of blood taurine, but the peak levels of the former did correlate with the latter ( P < 0.02). Patients with known coronary arterial disease had a higher resting [236 ± 69 μmol/l] level of blood taurine than normal subjects ( P < 0.001), which was further elevated [269 ± 80 μmol/l] following exercise ( P < 0.001). Thus, an elevated level of taurine in whole blood at the time of admission of patients with an acute cardiac pain suggested the diagnosis of either a myocardial infarction or unstable angina. The level of taurine may be utilised to differentiate the two conditions.

Does Exercise Training Alter Maximal Oxygen Uptake in Coronary Artery Disease During Long-Term Beta-Adrenergic Blockade?

The effects of long-term propranolol on the efficacy of exercise training on cardiovascular variables in patients with coronary artery disease were assessed in a community-based cardiac rehabilitation program. Eight men and one woman with significant coronary artery disease were randomly selected for this study. Each patient completed a maximal treadmill stress test (MTST) following the Bruce protocol while receiving propranolol 40–160 mg/d as a control study. Cardiorespiratory variables were measured at rest and at each stage of the treadmill test. These patients underwent an exercise training program for 12–16 weeks. Training sessions were for a minimum of 30–40 minutes, 3 times/wk, with training heart rates of 75% to 85% of the pretraining peak pulse rate. Training heart rate ranged from 98–128 beats/min. They were retested on a MTST afterward, on the same steady dose of propranolol. Cardiorespiratory variables, e.g., heart rate, blood pressure, maximum oxygen uptake (VO2max), carbon dioxide production (VCO2), gas exchange ratio (RER), ventilatory equivalents for oxygen and carbon dioxide (VE/VO2, VE/VCO2), oxygen pulse, etc., were measured every 30 seconds in relation to work increment. The mean values of VO2max, VO2max/kg, oxygen pulse, and total exercise time increased significantly after exercise training during propranolol intake. We conclude that the increase in VO2max due to increased stroke volume and peripheral O2 extraction, is a result of training with beta-adrenergic blockade.

Increased diastolic blood pressure response to exercise testing when coronary artery disease is suspected. An indication of severity.

One hundred and two consecutive patients with a history of chest pain or recent previous myocardial infarction underwent maximal treadmill stress testing and coronary angiography. The diastolic blood pressure response to exercise was evaluated independently of ST segment change and systolic blood pressure. In the presence of a normal systolic blood pressure response an increase in diastolic blood pressure of 15 mm Hg on at least two determinations during the same stage of exercise was considered abnormal. In 99 patients an accurate diastolic reading was possible. Of these, 61 had a normal diastolic blood pressure response; in 25 of these the ST segment was ischaemic and seven had three vessel coronary artery disease. Thirty eight patients had an abnormal diastolic blood pressure response and 27 of these had an ischaemic ST response. Of the 11 with a negative ST response for ischaemia one had left main stem disease, seven three vessel disease, and three two vessel disease. Patients with an abnormal diastolic response had greater ST depression with more angina at a reduced workload than those with a normal diastolic response. In patients with chest pain an abnormal increase in diastolic blood pressure on exercise reflects severe coronary artery disease. Although no false positives occurred in this study there was an appreciable number of false negatives (sensitivity 46%) in both patients with chest pain and those with infarction. An abnormal diastolic response therefore represents a useful additional diagnostic indicator of coronary artery disease when the ST segment response is normal or borderline. When the diastolic pressure becomes increased with or without ST changes the likelihood of severe coronary artery disease is increased.