Sport modality affects bradycardia level and its mechanisms of control in professional athletes.

We investigated the influence of sport modalities in resting bradycardia and its mechanisms of control in highly trained athletes. In addition, the relationships between bradycardia mechanisms and cardiac structural adaptations were tested. Professional male athletes (13 runners, 11 cyclists) were evaluated. Heart rate (HR) was recorded at rest on beat-to-beat basis (ECG). Selective pharmacological blockade was performed with atropine and esmolol. Vagal effect, intrinsic heart rate (IHR), parasympathetic (n) and sympathetic (m) modulations, autonomic influence (AI) and autonomic balance (Abal) were calculated. Plasmatic norepinephrine (high-pressure liquid chromatography) and cardiac structural adaptations (echocardiography) were evaluated. Runners presented lower resting HR, higher vagal effect, parasympathetic modulation (n), AI and IHR than cyclists (P<0.05). Abal, sympathetic modulation (m) and norepinephrine level were similar within athletes regardless of modality. The cardiac chambers were also similar between runners and cyclists (P=0.30). However, cyclists displayed higher septum and posterior wall thickness than runners (P=0.04). Further analysis showed a trend towards inverse correlation between IHR with septum wall thickness and posterior wall thickness (P=0.056). Type of sport influences the resting bradycardia level and its mechanisms of control in professional athletes. Resting bradycardia in runners is mainly dependent on an autonomic mechanism. In contrast, a cyclist's resting bradycardia relies on a non-autonomic mechanism probably associated with combined eccentric and concentric hypertrophy.

Accuracy of body mass index in diagnosing obesity in the adult general population.

BACKGROUND: Body mass index (BMI) is the most widely used measure to diagnose obesity. However, the accuracy of BMI in detecting excess body adiposity in the adult general population is largely unknown. METHODS: A cross-sectional design of 13 601 subjects (age 20-79.9 years; 49% men) from the Third National Health and Nutrition Examination Survey. Bioelectrical impedance analysis was used to estimate body fat percent (BF%). We assessed the diagnostic performance of BMI using the World Health Organization reference standard for obesity of BF%>25% in men and>35% in women. We tested the correlation between BMI and both BF% and lean mass by sex and age groups adjusted for race. RESULTS: BMI-defined obesity (> or =30 kg m(-2)) was present in 19.1% of men and 24.7% of women, while BF%-defined obesity was present in 43.9% of men and 52.3% of women. A BMI> or =30 had a high specificity (men=95%, 95% confidence interval (CI), 94-96 and women=99%, 95% CI, 98-100), but a poor sensitivity (men=36%, 95% CI, 35-37 and women=49%, 95% CI, 48-50) to detect BF%-defined obesity. The diagnostic performance of BMI diminished as age increased. In men, BMI had a better correlation with lean mass than with BF%, while in women BMI correlated better with BF% than with lean mass. However, in the intermediate range of BMI (25-29.9 kg m(-2)), BMI failed to discriminate between BF% and lean mass in both sexes. CONCLUSIONS: The accuracy of BMI in diagnosing obesity is limited, particularly for individuals in the intermediate BMI ranges, in men and in the elderly. A BMI cutoff of> or =30 kg m(-2) has good specificity but misses more than half of people with excess fat. These results may help to explain the unexpected better survival in overweight/mild obese patients.

Recognition, diagnosis and management of obesity after myocardial infarction.

OBJECTIVE: We investigated the documentation of obesity as a medical problem, and subsequent management recommendations, in patients after myocardial infarction (MI). DESIGN: We performed a cross-sectional analysis of a randomly selected sample of 627 patients discharged after an MI, from five US teaching hospitals between 1/1/01 and 12/31/02. Information was extracted from clinical notes using standardized definitions. RESULTS: Mean body mass index (BMI) was 31+/-13 kg/m2, which was documented in only 14% of patients and had to be calculated post hoc in the rest. Waist circumference and waist/hip ratio were not documented at all; 83% of patients were overweight, 55% obese, and 8% morbidly obese. In only 20% of patients with BMI> or =30 kg/m2 was the diagnosis of obesity documented either as a current medical problem, as part of past medical history or as a final diagnosis. A dietary counseling was carried out in 61% of patients with BMI> or =25 kg/m2 and in 61% of patients with BMI<25 kg/m2, P=0.96. Weight loss was described as part of the goals/plan at discharge in 7% of overweight and 9% of obese patients. There was no change in either the level of recognition of obesity (22 vs 19%, P=0.3) or in the proportion of obese patients for whom weight loss was described as part of the goals/plan at discharge (8 vs 10%, P=0.7) before (n=301) compared to after (n=326) the Call to Action in Obesity by the Surgeon General in December 2001. CONCLUSION: Obesity is underecognized, underdiagnosed and undertreated in persons with acute MI.

Pulmonary function in patients with reduced left ventricular function: influence of smoking and cardiac surgery.

STUDY OBJECTIVE: The impact of stable, chronic heart failure on baseline pulmonary function remains controversial. Confounding influences include previous coronary artery bypass or valve surgery (CABG), history of obesity, stability of disease, and smoking history. DESIGN: To control for some of the variables affecting pulmonary function in patients with chronic heart failure, we analyzed data in four patient groups, all with left ventricular (LV) dysfunction (LV ejection fraction [LVEF] < or =35%): (1) chronic heart failure, nonsmokers, no CABG (n = 78); (2) chronic heart failure, nonsmokers, CABG (n = 46); (3) chronic heart failure, smokers, no CABG (n = 40); and (4) chronic heart failure, smokers, CABG (n = 48). Comparisons were made with age- and gender-matched patients with a history of coronary disease but no LV dysfunction or smoking history (control subjects, n = 112) and to age-predicted norms. RESULTS: Relative to control subjects and percent-predicted values, all groups with chronic heart failure had reduced lung volumes (total lung capacity [TLC] and vital capacity [VC]) and expiratory flows (p < 0.05). CABG had no influence on lung volumes and expiratory flows in smokers, but resulted in a tendency toward a reduced TLC and VC in nonsmokers. Smokers with chronic heart failure had reduced expiratory flows compared to nonsmokers (p < 0.05), indicating an additive effect of smoking. Diffusion capacity of the lung for carbon monoxide (DLCO) was reduced in smokers and in subjects who underwent CABG, but not in patients with chronic heart failure alone. There was no relationship between LV size and pulmonary function in this population, although LV function (cardiac index and stroke volume) was weakly associated with lung volumes and DLCO. CONCLUSIONS: We conclude that patients with chronic heart failure have primarily restrictive lung changes with smoking causing a further reduction in expiratory flows.

Vitamin E supplementation in the prevention of coronary heart disease.

Vitamin E consists of a number of compounds, tocopherols and tocotrienols, that function as lipid-soluble antioxidants. A hypothesis is that vitamin E may slow the progression of atherosclerosis by blocking the oxidative modification of low-density lipoprotein cholesterol and thus decrease its uptake into the arterial lumen. Basic science and animal studies have generally supported this hypothesis. Observational studies have primarily assessed patients with no established coronary heart disease (CHD), and results have generally supported a protective role of vitamin E in CHD. Early primary and secondary prevention clinical trials (Alpha-Tocopherol, Beta-Carotene Cancer Protection study and Cambridge Heart Antioxidant Study) showed mixed results. Despite years of encouraging evidence from basic science and observational studies, 3 large randomized clinical trials (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico, Heart Outcomes Prevention Evaluation, and Primary Prevention Project) with a combined total of more than 25,000 patients failed to show a significant benefit with vitamin E taken as a dietary supplement for the prevention of CHD. Four large randomized primary prevention trials currently under way should add to our knowledge. The American Heart Association has recommended consumption of a balanced diet with emphasis on antioxidant-rich fruits and vegetables but has made no recommendations regarding vitamin E supplementation for the general population. Although vitamin E supplementation seems to be safe for most people, recommendations from health care professionals should reflect the uncertainty of established benefit as demonstrated in clinical trials.

Management of coronary risk factors by registered nurses versus usual care in patients with unstable angina pectoris (a chest pain evaluation in the emergency room [CHEER] substudy).

This study examined whether nurses could manage coronary risk factors in patients with unstable angina more effectively than physicians practicing usual care. Three hundred twenty-six patients were randomized in the emergency room to a 6-month program of risk factor management by a registered nurse versus participation in usual care. The nurse intervention consisted of a 30-minute counseling visit at 6 to 10 days after the chest pain episode and a second 30-minute session 1 month later. Multiple risk factors were assessed and addressed: smoking, blood lipids, blood pressure, blood glucose, physical inactivity, weight, psychological stress, and social isolation. Compared with usual care, nurse intervention patients significantly reduced both triglycerides (-29 +/- 8 vs 5 +/- 6 mg/dl; p <0.0004) and weight (-0.9 +/- 3.3 vs +0.1 +/- 2.1 kg; p = 0.0071), and had corresponding improvements in self-reported diet compliance and exercise (+34 +/- 106 vs +9 +/- 98 minutes, p = 0.0491). No significant differences between groups were observed in terms of 6-month changes in total, high-density lipoprotein, or low-density lipoprotein cholesterol, blood pressure, fasting blood glucose, percent body fat or waist-hip ratio, or psychological distress scores. The 6-month rate of recurrent events (cardiac death, out-of-hospital cardiac arrest, myocardial infarction) and/or revascularizations (coronary artery bypass surgery or coronary angioplasty) was lower in the nurse intervention group (1% vs 9%; p = 0.002). We conclude that a nurse-delivered risk factor intervention program for patients with chest pain is feasible and more effective than usual care in terms of fostering lifestyle changes that may lower coronary risk.

Ventilatory constraints during exercise in patients with chronic heart failure.

We examined the degree of ventilatory constraint in patients with a history of chronic heart failure (CHF; n = 11; mean +/- SE age, 62 +/- 4 years; cardiac index [CI], 2.0 +/- 0.1; and ejection fraction [EF], 24 +/- 2%) and in control subjects (CTLS; n = 8; age, 61 +/- 5 years; CI, 2.6 +/- 0.3) by plotting the tidal flow-volume responses to graded exercise in relationship to the maximal flow-volume envelope (MFVL). Inspiratory capacity (IC) maneuvers were performed to follow changes in end-expiratory lung volume (EELV) during exercise, and the degree of expiratory flow limitation was assessed as the percent of the tidal volume (VT) that met or exceeded the expiratory boundary of the MFVL. CHF patients had significantly (p < 0.05) reduced baseline pulmonary function (FVC, 76 +/- 4%; FEV(1), 78 +/- 4% predicted) relative to CTLS (FVC, 99 +/- 4%; FEV(1), 102 +/- 4% predicted). At peak exercise, oxygen consumption (VO(2)) and minute ventilation (V(E)) were lower in CHF patients than in CTLS (VO(2), 17 +/- 2 vs 32 +/- 2 mL/kg/min; VE, 56 +/- 4 vs 82 +/- 6 L/min, respectively), whereas VE/carbon dioxide output was higher (42 +/- 4 vs 29 +/- 5). In CTLS, EELV initially decreased with light exercise, but increased as VE and expiratory flow limitation increased. In contrast, the EELV in patients with CHF remained near residual volume (RV) throughout exercise, despite increasing flow limitation. At peak exercise, IC averaged 91 +/- 3% and 79 +/- 4% (p < 0.05) of the FVC in CHF patients and CTLS, respectively, and flow limitation was present over > 45% of the VT in CHF patients vs < 25% in CTLS (despite the higher VE in CTLS). The least fit and most symptomatic CHF patients demonstrated the lowest EELV, the greatest degree of flow limitation, and a limited response to increased inspired carbon dioxide during exercise, all consistent with VE constraint. We conclude that patients with CHF commonly breathe near RV during exertion and experience expiratory flow limitation. This results in VE constraint and may contribute to exertional intolerance.

Is rest or exercise hypertension a cause of a false-positive exercise test?

STUDY OBJECTIVES: To determine if a history of hypertension or an exaggerated rise in exercise systolic BP is associated with a false-positive exercise ECG. DESIGN, SETTING, AND PATIENTS: Retrospective analysis of the associations between exercise-induced ST-segment depression and a history of hypertension, exercise systolic BP, and several other clinical and exercise test variables. Among 20,097 patients referred for exercise tomographic thallium imaging in a nuclear cardiology laboratory at a tertiary care center, 1,873 patients met inclusion criteria for this study, which included no history of myocardial infarction or coronary artery revascularization, a normal resting ECG, and normal exercise thallium images. RESULTS: False-positive ST-segment depression occurred in 20% of the population. A history of hypertension was actually associated with a lower likelihood of ST-segment depression (odds ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.89; p = 0. 004). A higher peak exercise systolic BP was associated with a higher likelihood of ST-segment depression (odds ratio, 1.08 for each 10-mm Hg increase in systolic BP; 95% CI, 1.03 to 1.14; p < 0. 001). However, the association between peak exercise systolic BP and ST-segment depression was so weak that this measurement could not be predictive in the individual patient (R(2) = 0.2%). For every 20-mm Hg increase in peak exercise systolic BP, the percentage of patients with ST-segment depression increased by only 3%. CONCLUSIONS: In patients with normal resting ECGs, we conclude the following: (1) a history of hypertension is not a cause of a false-positive exercise test, and (2) higher exercise systolic BP is a significant but weak predictor of ST-segment depression.

Non-physician supervision of cardiopulmonary exercise testing in chronic heart failure: safety and results of a preliminary investigation.

PURPOSE: In the current era of efficient use of personnel and cost containment, the use of non-physicians in selected roles previously occupied exclusively by physicians has become increasingly prevalent. Traditionally, physicians have directly supervised graded exercise testing of patients with chronic heart failure. The purpose of this prospective pilot investigation was to determine the safety and results of non-physician supervised exercise testing of these high-risk patients. METHODS: Two hundred eighty-nine consecutive outpatients (211 men, 78 women) with left ventricular ejection fractions of < or = 35% were referred for cardiopulmonary exercise testing. Symptom-limited treadmill graded exercise tests were supervised by paramedical personnel with a physician immediately available, but not present in the lab. RESULTS: Nonsustained ventricular tachycardia was present during exercise in approximately 20% of patients. Test-limiting hypotension was documented in 5% of subjects. Only one serious event occurred during the 289 exercise tests, an episode of ventricular fibrillation with a successful resuscitation outcome. Peak exercise respiratory exchange ratio averaged 1.10 +/- 0.14, consistent with a near-maximal patient effort. Peak oxygen uptake was 18 +/- 5 ml/kg/min. CONCLUSIONS: Supervision of cardiopulmonary graded exercise testing in properly screened patients with severe systolic left ventricular dysfunction by experienced non-physicians appears to be reasonably safe and the results are suitable for clinical decision making. Such a practice is an attractive cost-containment strategy and deserves further investigation.

Achieving National Cholesterol Education Program goals for low-density lipoprotein cholesterol in cardiac patients: importance of diet, exercise, weight control, and drug therapy.

OBJECTIVE: To determine how frequently the National Cholesterol Education Program (NCEP) goal of a low-density lipoprotein (LDL) cholesterol level of 100 mg/dL or less is achieved in clinical practice in patients with coronary artery disease and what fraction of patients can achieve this goal without drug therapy. DESIGN: We examined the results of lipid management in 152 consecutive patients who had completed cardiac rehabilitation after an acute coronary event. Patients were randomized to follow-up by specially trained nurses or by preventive cardiologists, and they were not receiving lipid-lowering drugs at the start of the study. MATERIAL AND METHODS: Patients were given aggressive diet and exercise recommendations and lipid-lowering drugs in accordance with NCEP guidelines. Follow-up was continued for a mean of 526 days after the first lipid assessment subsequent to the coronary event. Multiple logistic regression analysis was used to identify independent predictors of a final LDL cholesterol level of 100 mg/dL or less. RESULTS: Of the study group, 39% achieved the NCEP goal LDL cholesterol level of 100 mg/dL or less. Characteristics of the patients with LDL cholesterol levels of 100 mg/dL or less in comparison with those with LDL cholesterol levels of more than 100 mg/dL included a greater frequency of drug therapy (65% versus 38%), more rigorous dietary compliance, longer follow-up (586 +/- 317 days versus 493 +/- 264 days), more favorable weight change (-0.3 +/- 4.9 kg versus +1.7 +/- 5.0 kg), and more extensive weekly exercise (183 +/- 118 minutes versus 127 +/- 107 minutes). CONCLUSION: The registered nurses managed the lipids of these patients as effectively as did the preventive cardiologists. Appropriate drug therapy was the most important factor in achieving an LDL cholesterol level of 100 mg/dL or less, but 35% of patients attaining this NCEP goal were not receiving drug therapy. Exercise, dietary compliance, and weight loss were also important factors.

Prognostic significance of exercise-induced systemic hypertension in healthy subjects.

Exercise hypertension has been suggested to predict future resting hypertension, but its significance in terms of cardiovascular risk has not been defined. To assess the prognostic significance of exercise hypertension, 150 healthy, asymptomatic subjects with normal resting blood pressures and exercise systolic blood pressures > or =214 mm Hg (i.e., >90th percentile) on Bruce treadmill tests were identified retrospectively and age- and gender-matched with subjects with exercise systolic blood pressures of 170 to 192 mm Hg (40th to 70th percentiles). Subjects were contacted by survey a mean of 7.7+/-2.9 years after the index treadmill test. The survey response rate was 93%. There were 12 deaths, including 8 in the exercise hypertension group. A major cardiovascular event, defined as cardiovascular death, myocardial infarction, stroke, coronary angioplasty, or coronary bypass graft surgery occurred in 5 controls and 10 subjects with exercise hypertension. At follow-up, 13 controls and 37 subjects with exercise hypertension were now diagnosed as having resting hypertension. In multivariate analysis, exercise hypertension was not a significant predictor for death or any individual cardiovascular event, but was for total cardiovascular events and new resting hypertension. The multivariate risk ratio for exercise hypertension was 3.62 (p = 0.03) in predicting a major cardiovascular event. Other significant predictors included body mass index and age. For predicting new resting hypertension, the multivariate odds ratio for exercise hypertension was 2.41 (p = 0.02). These data suggest that exercise hypertension carries a small but significant risk for major cardiovascular events in healthy, asymptomatic persons with normal resting blood pressures.

A clinical trial of a chest-pain observation unit for patients with unstable angina. Chest Pain Evaluation in the Emergency Room (CHEER) Investigators.

BACKGROUND: Nearly half of patients hospitalized with unstable angina eventually receive a non-cardiac-related diagnosis, yet 5 percent of patients with myocardial infarction are inappropriately discharged from the emergency department. We evaluated the safety, efficacy, and cost of admission to a chest-pain observation unit (CPU) located in the emergency department for such patients. METHODS: We performed a community-based, prospective, randomized trial of the safety, efficacy, and cost of admission to a CPU as compared with those of regular hospital admission for patients with unstable angina who were considered to be at intermediate risk for cardiovascular events in the short term. A total of 424 eligible patients were randomly assigned to routine hospital admission (a monitored bed under the care of the cardiology service) or admission to the CPU (where patients were cared for according to a strict protocol including aspirin, heparin, continuous ST-segment monitoring, determination of creatine kinase isoenzyme levels, six hours of observation, and a study of cardiac function). The CPU was managed by the emergency department staff. Patients whose test results were negative were discharged, and the others were hospitalized. Primary outcomes (nonfatal myocardial infarction, death, acute congestive heart failure, stroke, or out-of-hospital cardiac arrest) and use of resources were compared between the two groups. RESULTS: The 212 patients in the hospital-admission group had 15 primary events (13 myocardial infarctions and 2 cases of congestive heart failure), and the 212 patients in the CPU group had 7 events (5 myocardial infarctions, 1 death from cardiovascular causes, and 1 case of congestive heart failure). There was no significant difference in the rate of cardiac events between the two groups (odds ratio for the CPU group as compared with the hospital-admission group, 0.50; 95 percent confidence interval, 0.20 to 1.24). No primary events occurred among the 97 patients who were assigned to the CPU and discharged. Resource use during the first six months was greater among patients assigned to hospital admission than among those assigned to the CPU (P<0.01 by the rank-sum test). CONCLUSIONS: A CPU located in the emergency department can be a safe, effective, and cost-saving means of ensuring that patients with unstable angina who are considered to be at intermediate risk of cardiovascular events receive appropriate care.

Interaction of CCK and 8-OH-DPAT in the satiation of alcohol intake.

Administration of the neuropeptide cholecystokinin (CCK) is known to reduce food and alcohol intake and preference. The food satiation effect of CCK is reportedly dependent on serotonergic neurotransmission. Administration of 8-OH-DPAT, a serotonin1A autoreceptor agonist, reduces the ability of CCK to inhibit feeding. We determined if CCK's alcohol satiation effect also depends on activity of serotonergic neurons by administering 8-OH-DPAT (120-240 microg/kg) to 23-h water-deprived female and male rats, followed 1 h later by i.p. injection of CCK (4 microg/kg) and 30-min access to 5% w/v ethanol. 8-OH-DPAT significantly (p < 0.05) interacted with CCK, and reduced CCK's ethanol satiation effect when given i.p. but increased CCK's effect when given s.c. Female rats showed this interaction of 8-OH-DPAT with CCK at a higher dose than males when given i.p., but females were more sensitive to s.c. 8-OH-DPAT's ability to reduce ethanol intake. Results are consistent with previous findings of dose-, sex-, and route-dependent biphasic effects of 8-OH-DPAT on feeding and ethanol intake. A partial dependence of CCK's alcohol satiation effect on serotonergic neurotransmission is revealed in this design.

Comparison of responses of men to immersion in circulating water at 40.0 and 41.5 degrees C.

BACKGROUND: The recommended maximum water temperature for public hot tubs has been set at 40.0 degrees C, but no research has been published on human immersion in hot water at higher temperatures. HYPOTHESIS: We hypothesized that thermoregulatory and cardiovascular responses at two water temperatures would be proportional to the water:blood temperature gradients. METHODS: Six healthy men were immersed for 21 min in circulating hot water at 40.0 and 41.5 degrees C in separate trials in random order 1-3 wk apart. Measurements included heart rate, systolic BP, esophageal, rectal, and non-immersed skin temperatures, sweat rate, and perceived comfort. RESULTS: The rise in all body temperatures, sweat rate, and heart rate were significantly greater in the 41.5 vs. 40.0 degrees C water. Peak esophageal temperatures were 38.3 +/- 0.2 degrees C vs. 37.8 +/- 0.03 degrees C, peak sweat rates were 0.48 +/- 0.05 vs. 0.32 +/- 0.03 kg x m(-2) x h(-1), and peak heart rates were 123 +/- 7 vs. 108 +/- 5 bpm, respectively. Systolic BPs followed different patterns of response in each trial, whereas diastolic pressures were not different between trials. Comfort at each level of immersion was reduced during the 41.5 degrees C trial compared with the 40.0 degrees C in excess of that predicted by difference in esophageal temperature between the trials. CONCLUSIONS: These results suggest that risks of hyperthermia or adverse cardiovascular effects in hot tubs may not be greater in water above 40.0 degrees C unless perceptual judgment is impaired. Hypotension when standing to exit the tub occurred in both trials and may represent a potential hazard to hot tub use.

Effect of intervention for psychological distress on rehospitalization rates in cardiac rehabilitation patients.

Psychosocial factors affect the development of coronary heart disease and morbidity and mortality of patients with known coronary heart disease. A prior study has shown that psychological distress in patients with known coronary heart disease increased medical and economic costs. This study examined the effects of commonly available psychological interventions offered to patients entering cardiac rehabilitation after hospitalization for angina, myocardial infarction, angioplasty, or coronary artery bypass grafting. A total of 380 patients were screened with the Symptom Checklist-90-Revised (SCL-90-R). Those with T-scores > or = 63 (> or = 91 percentile) on the General Severity Index (GSI) subscale were randomly assigned to usual care or special intervention. Special intervention included a psychiatric evaluation, plus one to seven sessions of behavioral therapy. The percentage of patients rehospitalized for cardiac symptoms within 12 months of psychological evaluation was 43% for special intervention and 40% for usual care (NS). A correction for crossover between the treatment groups resulted in a favorable trend toward intervention, with 35% of the psychologically treated patients rehospitalized vs. 48% of the untreated patients (NS). Although there was a nonsignificant reduction of the SCL-90-R's GSI T-score, the depression score was significantly reduced in the special intervention group.

Cardiovascular responses in a whirlpool bath at 40 degrees C versus user-controlled water temperatures.

OBJECTIVE: To compare cardiovascular responses in a whirlpool bath at 40 degrees C versus user-controlled water temperature (UCT). MATERIAL AND METHODS: In an experimental study, six healthy men, 36 to 43 years of age, participated in two randomly assigned trials of whirlpool bath use for 25 minutes at 40 degrees C and UCT. Water temperature, esophageal temperature (Tes) heart rate (HR), systolic blood pressure (SBP), and perceived comfort were monitored before immersion and at 5-minute intervals during immersion. RESULTS: Although the mean water temperature during the UCT trial was slightly below 40 degrees C (39.4 +/- 2.0 degrees C), it varied considerably among subjects (from 36.5 +/- 2.1 degrees C to 42.5 +/- 1.7 degrees C). Peak Tes9 HR, and SBP were not significantly different between the two trials, although the UCT trial had greater variability. No adverse effects were observed. Mild or moderate overheating was reported by four subjects in the 40 degrees C trial and two subjects in the UCT trial, and mild chest pain, light-headedness, dyspnea, and nausea were reported by one subject during the UCT trial. A trend toward higher comfort ratings was noted in the UCT than in the 40 degrees C trial, especially during the final 10 minutes of immersion. CONCLUSION: These data show that cardiovascular responses to whirlpool bathing for 25 minutes at 40 degrees C are mild. In comparison with the 40 degrees C trial, peak Tes9, HR, and SBP under UCT conditions were not, on the average, significantly higher, although more variability existed among the subjects.

Comparison of peak exercise oxygen uptake in men versus women in chronic heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Results of exercise testing in 150 patients with chronic heart failure show that women were characterized by shorter exercise time, peak oxygen consumption, and lower peak oxygen pulse than men. There was a 4.1-ml/kg/min difference in peak oxygen uptake between genders after the adjustment of age, peak heart rate, respiratory exchange ratio, ejection fraction, and etiology of heart failure.

Dual-chamber pacing for hypertrophic cardiomyopathy: a randomized, double-blind, crossover trial.

OBJECTIVES: In a double-blind, randomized, crossover trial we sought to evaluate the effect of dual-chamber pacing in patients with severe symptoms of hypertrophic obstructive cardiomyopathy. BACKGROUND: Recently, several cohort trials showed that implantation of a dual-chamber pacemaker in patients with severely symptomatic hypertrophic obstructive cardiomyopathy can relieve symptoms and decrease the severity of the left ventricular outflow tract gradient. However, the outcome of dual-chamber pacing has not been compared with that of standard therapy in a randomized, double-blind trial. METHODS: Twenty-one patients with severely symptomatic hypertrophic obstructive cardiomyopathy were entered into this trial after baseline studies consisting of Minnesota quality-of-life assessment, two-dimensional and Doppler echocardiography and cardiopulmonary exercise tests. Nineteen patients completed the protocol and underwent double-blind randomization to either DDD pacing for 3 months followed by backup AAI pacing for 3 months, or the same study arms in reverse order. RESULTS: Left ventricular outflow tract gradient decreased significantly to 55 +/- 38 mm Hg after DDD pacing compared with the baseline gradient of 76 +/- 61 mm Hg (p < 0.05) and the gradient of 83 +/- 59 mm Hg after AAI pacing (p < 0.05). Quality-of-life score and exercise duration were significantly improved from the baseline state after the DDD arm but were not significantly different between the DDD arm and the backup AAI arm. Peak oxygen consumption did not significantly differ among the three periods. Overall, 63% of patients had symptomatic improvement during the DDD arm, but 42% also had symptomatic improvement during the AAI backup arm. In addition, 31% had no change and 5% had deterioration of symptoms during the DDD pacing arm. CONCLUSIONS: Dual-chamber pacing may relieve symptoms and decrease gradient in patients with hypertrophic obstructive cardiomyopathy. In some patients, however, symptoms do not change or even become worse with dual-chamber pacing. Subjective symptomatic improvement can also occur from implantation of the pacemaker without its hemodynamic benefit, suggesting the role of a placebo effect. Long-term follow-up of a large number of patients in randomized trials is necessary before dual-chamber pacing can be recommended for all patients with severely symptomatic hypertrophic obstructive cardiomyopathy.