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PubMedDate not supplied

Experience with partial cricoid resection and thyrotracheal anastomosis.

Since 1973, 28 patients have undergone tracheal and subglottic resection with reconstruction by primary laryngotracheal anastomosis. Nine patients had postintubation stricture, eight had blunt trauma with cricotracheal disruption, seven had a neoplasm, two had an inhalation burn, and two had idiopathic stenosis. In all cases, the anterior cricoid arch was completely resected and a submucosal segment of the posterior cricoid plate was partially resected. A posterior shell of cricoid plate was preserved in 21 patients with intact laryngeal nerve function. Postoperatively, a Montgomery T-tube was used to stent the anastomosis and subglottic area in ten patients, all of whom had residual injury or disease at or immediately below the level of the cords. The proximal arm of the T-tube was positioned above the vocal cords. The tube was removed within 1 month in eight patients and remained for 3 and 18 months in the other two. The extent of resection varied from 2.5 to 7 cm. Tension-relieving procedures were added in 13 cases. Fourteen patients have been followed longer than 5 years, and five patients for more than 10 years. A widely patent anastomosis was maintained in 26 patients. In two patients, a partial restenosis resulted in some limitations of exercise tolerance. Voice and exercise tolerance have not deteriorated with the passage of time. Recurrent laryngeal nerve function was completely preserved in 20 of the 21 patients whose nerve function was intact before operation.

Adolescent↗
PubMedDate not supplied

Changes in exercise capacity following cardiac rehabilitation in patients stratified according to age and gender. Results of the Massachusetts Association of Cardiovascular and Pulmonary Rehabilitation Multicenter Database.

BACKGROUND: Using information collected prospectively from a multicenter cardiac rehabilitation database, this study was designed to evaluate baseline exercise tolerance and subsequent change in functional capacity among consecutive patients enrolled in supervised cardiac rehabilitation stratified according to age and gender. In addition, the study evaluated change in functional capacity among those with the lowest initial exercise tolerance (<5 METS) and assessed patient factors that correlate to the highest relative improvements in functional capacity after training. METHODS: A total of 778 patients performed an initial exercise test upon entry into cardiac rehabilitation, during which peak heart rate, blood pressure, and estimated peak MET levels were derived, and ischemic responses were evaluated. After 10 +/- 2 weeks of supervised prescribed exercise, 500 patients who completed the program performed follow-up exercise testing. RESULTS: The subjects included 558 men (72%) and 220 women (28%) of whom 492 (63%) were <65 years, 241 (31%) were 65 to 75 years, and 45 (6%) were >75 years. At baseline, the peak initial MET level for men was 8.6 +/- 3.4 METS and for women was 6.0 +/- 2.6 METs. The peak initial MET level declined with age: age <65 = 8.9 +/- 3.4 METS; age 65 to 75 = 6.6 +/- 2.6 METS; and age >75 = 5.7 +/- 2.9 METS. When stratified according to age and gender, the baseline exercise tolerance for men significantly (P <.0001) declined with age and was higher than that of women <65 and 65 to 75 years of age. After training, the relative improvement in exercise tolerance for each age and/or gender subgroup was: age <65: men 36%, women 41%; age 65 to 75: men 36%, women 50%; and age >75: men 36%, women 32%. Among 163 patients with an initial peak MET level <5, exercise tolerance rose from 4.1 +/- 0.7 to 8.3 +/- 3.5 METS (P <.0001). Multivariate analysis demonstrated that the greatest change in exercise tolerance with training was associated with those compliant patients with initial peak METS <5. No significant net change in the occurrence of exercise-induced ischemia was observed. CONCLUSIONS: Among consecutive patients enrolled in cardiac rehabilitation, baseline exercise tolerance differs relative to age and gender, with male gender and younger age demonstrating the highest functional capacity. Exercise training yielded significant improvements in exercise tolerance among men and women of every age group including those older than 75 years, and particularly among those with an initial peak MET level <5. Thus, referral to cardiac rehabilitation programs should be advocated for both men and women, and should not be limited by age.

Adult↗
PubMed1987

[Activity-initiated rate-adapted pacemaker therapy. Clinical results].

In a prospective study of 23 patients the clinical effects of rate-adapted activity-sensed (by mechanical resonance oscillations) pacing (Activitrax system) were tested over a mean period of 8.1 +/- 3.8 months. This form of pacemaker treatment was used when, after exercise and on long-term ECG monitoring, the spontaneous heart rate had not exceeded 85 beats per min and there had been symptoms of decreased exercise tolerance. Lasting improvement in physical exercise tolerance was achieved in 11 of 17 patients after changing from fixed-rate to rate-adapted pacing. Treadmill ergometry, randomised in the fixed-rate or rate-adapted mode, brought about a significant rise in exercise tolerance (P greater than 0.01). Contrary to results after external influences, insufficient rate increases in five patients in the course of static stress was of clinical significance and thus narrow the indications for this type of pacing.

Adult↗
PubMed1991

Prediction of the exercise-heat tolerance of soldiers wearing protective overgarments.

The purpose of this investigation was to see whether subject characteristics and physiologic measurements predicted exercise-heat tolerance (EHT) and voluntary tolerance time in young soldiers. A total of 18 unacclimatized males attempted six 50-min periods of treadmill walking (4.0 km.h-1, 0% grade, 33 degrees C db, 20% rh) while wearing protective overgarments. Two post hoc groups of soldiers were defined: high EHT (H) and low EHT (L), having mean (+/- S.E.) tolerance times of 360 +/- 0 and 222 +/- 12 min, respectively. Significant (p less than 0.05) H vs. L differences were observed in pretrial body mass, percent fat, and mass-to-surface area ratio (M/SA), as well as 170 min HR, Tsk and heat storage. The first three of these factors indicated that preexercise anthropomorphic characteristics may be used to distinguish H from L. The HR and Tsk differences were interpreted to mean that L experienced greater cardiovascular strain in protective overgarments because of a higher Tsk, which resulted in increased pooling of blood in cutaneous vessels, decreased cardiac filling pressure, and increased fatigue. Because HR variables were the strongest correlates of exercise tolerance time (r2 = 0.60 for HR at 170 min, r2 = 0.83 for time to reach HR of 160 beats.min-1) a novel HR monitoring technique was proposed which uses a wrist-mounted cardiotachometer to predict tolerance time.

Adult↗
PubMed1983

Influence of time of day on reactions to cycling at a fixed high intensity.

The circadian cycle in all-out competitive performance may be due to changes in motivational drive to tolerate strenuous exercise rather than to rhythms in maximal physiological functions. This experiment explored the hypothesis that a fixed relative loading of high intensity aerobic effort could be sustained for longer in the evening compared with the morning. Eight females cycled to exhaustion at 95% VO2 max at 06.30 h. and at 22.00 h. after a 5 min, moderate load of 40% VO2 max. Oral temperature was 0.4 degrees C higher at 22.00 h. compared with the earlier time. Perceived exertion showed no significant effect of time of day at either work load but exercise tolerance time, total work done and peak lactate production were significantly greater at 22.00 h. (p = 0.05). Perceived exertion at the high load was significantly related to endurance time (r = -0.77) and to the rating at the low work level (r = 0.75). Peak lactate was not significantly correlated with the time to exhaustion (p less than 0.05). It was concluded that superior exercise performance in the evening may be attributed to a greater tolerance for high intensity exercise which is closely associated with the acrophase in body temperature.

Adult↗
PubMed1995

Role of skeletal muscle metabolism in exercise capacity of patients with myocardial infarction studied by phosphorus-31 nuclear magnetic resonance.

Patients with congestive heart failure reportedly show a poor correlation between cardiac function and exercise tolerance. Recent studies have demonstrated that skeletal muscle is the main factor that limits exercise tolerance. However, the relationship between high-energy phosphate metabolism in skeletal muscle and exercise tolerance has not been well defined. Exercise capacity was assessed in 35 subjects with myocardial infarction in terms of peak oxygen consumption (peak VO2) during treadmill exercise with an analysis of expired gases. On the same day, changes in high-energy phosphates in finger flexor muscle during handgrip exercise were measured by magnetic resonance spectrometry. Phosphocreatine (PCr) utilization and the decrease in pH during handgrip exercise were significantly greater in patients with a poor exercise capacity and their time constant of recovery of PCr was prolonged. The ratios of PCr/Pi (Pi: inorganic phosphate) and PCr/HMPA (HMPA: hexamethylphosphoramide) during exercise and the time constant of recovery of PCr were significantly correlated with peak VO2. These results suggest that skeletal muscle metabolism governs exercise tolerance.

Adult↗
PubMed1994

[Comparison of nisoldipine and diltiazem in the treatment of effort angina pectoris].

BACKGROUND: In order to evaluate the benefits of a calcium-antagonist medium-term treatment, 20 patients with effort stable angina pectoris were treated with nisoldipine in comparison to diltiazem. METHODS: Twenty patients with stable effort angina completed a double-blind, placebo controlled trial, comparing 10 twice daily nisoldipine per os and diltiazem 120 three times daily per os for 28 days. After wash-out, placebo and drug period, ergometer stress tests were performed. Exercise tolerance, angina frequency, nitrate consumption and side effects were evaluated. RESULTS: Our results showed that both drugs significantly increased exercise tolerance. Exercise duration was 330 +/- 107 sec after placebo, 397 +/- 106 sec after nisoldipine (p < 0.05) and 378 +/- 99 sec after diltiazem (p < 0.05). Effort angina episodes decreased from 20 after placebo to 8 after nisoldipine and diltiazem. Both drugs reduced rate-pressure product at submaximal exercise in comparison to placebo. There were no differences at peak exercise between placebo or drug periods. Both drugs similarly reduced nitrate consumption and weekly effort angina attacks. No patients referred serious side-effects. CONCLUSIONS: nisoldipine, like diltiazem, is an effective drug in the treatment of stable effort angina. Moreover, the therapeutic effects of nisoldipine during medium-term treatment are probably related to decrease in oxygen consumption.

Administration, Oral↗
PubMed1999

Higher systemic arterial compliance is associated with greater exercise time and lower blood pressure in a young older population.

OBJECTIVES: Arterial compliance is an important therapeutic target in older individuals in whom stiffening of the proximal arterial circulation is thought to underlie systolic hypertension and increased cardiac work. We have shown previously that arterial compliance is related to aerobic fitness and that it is increased in young (20 to 35 years old), previously sedentary individuals by a 4-week period of moderate aerobic training. The extent to which compliance relates to exercise performance in a random selection of young older patients has not been reported previously. Therefore, we examined the interrelationship between systemic arterial compliance (SAC) and time to cessation of exercise during a standard treadmill exercise test in an older population. DESIGN: A cross-sectional survey. METHODS: SAC was estimated at rest using simultaneous recordings of ascending aortic flow and carotid applanation tonometry in 43 subjects aged 67 +/- 7 years (mean +/- SD; 24 men and 19 women). Treadmill exercise testing was performed using a modified Bruce protocol. Aerobic capacity was assessed as Heart Rate-Blood Pressure product and exercise tolerance as total treadmill time. RESULTS: SAC and exercise tolerance were related to gender, with men exhibiting greater exercise reserve and higher SAC than women. There was a significant positive correlation between SAC and time to cessation of exercise (r = .34; P = .03), with a negative correlation between SAC and resting heart rate-blood pressure product (r = -.66; P < .001). SAC was correlated with height and blood pressure. Exercise tolerance was related to height (P < .02). CONCLUSIONS: These data indicate a positive association between SAC and fitness level in healthy older people and an inverse association between SAC and systolic blood pressure. Our findings are consistent with either (1) acquisition of a more compliant circulation and lower blood pressure through more physical activity or (2) that a more compliant arterial circulation and lower blood pressure permit greater athletic performance.

Aged↗
PubMed1998

Improved oxygen utilization during mild exercise in heart failure.

In heart failure with low cardiac output, exercise tolerance is reduced despite modulated regional blood distribution and oxygen extraction. However, low cardiac output does not necessarily lead to reduced exercise tolerance especially during mild exercise. In the present study, in order to understand the mechanisms regulating exercise tolerance in heart failure, we measured oxygen consumption (VO2) and cardiac output (CO) during both mild and intense exercise. Patients with heart failure were divided into 2 groups; group L (n = 8) consists of patients with low anaerobic threshold (AT) < 13 ml/min per kg and group H (n = 7) consisting of patients with AT > 13 ml/min per kg. At rest, VO2 was similar between groups L and H, whereas CO was lower in group L than in group H (3.5 + 0.3 vs 4.8 + 1.4 ml/min, p < 0.01). Increase in VO2 during warm-up exercise was not significant between the 2 groups (7.4 +/- 0.5 (group L) vs 6.2 +/- 0.3 ml/min per kg (group H), ns), but increase in CO was lower in group L than in group H (2.5 +/- 0.6 vs 3.4 +/- 0.4 ml/min, p < 0.01). After warm-up to the AT point, however, the increase in not only VO2 but also CO was markedly reduced in group L than in group H (VO2: 0.5 +/- 0.4 vs 3.7 +/- 0.8 ml/min per kg, p < 0.01, CO: 0.2 +/- 0.3 vs 1.1 +/- 0.3 L/min, p < 0.01). Based on these measurements, we calculated the arteriovenous oxygen difference (c(A-V)O2 difference) during exercise in individual patients using Fick's equation. The c(A-V)O2 difference was markedly increased in severe heart failure during the warm-up stage, but between the end of warm-up and the AT point, it remained at the same level as that of group H. These results suggest the presence of a unique mechanism regulating the c(A-V)O2 difference in severe heart failure patients, activation of which may, at least during mild exercise, contribute to efficient oxygen delivery to the peripheral tissues thus compensating for the jeopardized exercise tolerance in those patients.

Aged↗
PubMed2004

Minimally supervised home rehabilitation improves exercise capacity and health status in patients with COPD.

OBJECTIVE: The purpose of this study was to investigate the effects on exercise tolerance and quality of life of an outpatient rehabilitation program implemented at home without a physiotherapist's direct supervision in patients with chronic obstructive lung disease. DESIGN: Patients with moderate chronic obstructive pulmonary disease were studied. The rehabilitation program included lower limb exercise on a stationary bicycle and upper limb exercise and stretching, together with education, and it lasted for 12 wks. Every 2 wks, a physiotherapist contacted patients by phone to evaluate their compliance with the rehabilitation program and any adverse effects. The main measures of outcome were the Health Status Index, cycle ergometer test, forced expiratory volume in 1 sec, and forced vital capacity. Patients were evaluated at the baseline and at 12 wks. RESULTS: A total of 32 patients were recruited and 28 (mean age, 70.4 yrs) completed the trial. After pulmonary rehabilitation, a significant improvement was found in seven of the nine Health Status Index quality-of-life subscales. Exercise tolerance also improved significantly, whereas no variation was observed in pulmonary function tests. There was no correlation between the improvement in quality of life and the improvement in exercise tolerance. The improvements in the Health Status Index physical function and general health subscales correlated negatively with forced expiratory volume in 1 sec (percentage of predicted value) and positively with residual volume/total lung capacity ratio. The improvement in exercise tolerance (expressed in watts or as maximum oxygen uptake), but not in quality-of-life indexes, was associated negatively with age and positively with weight, cognitive function, and forced expiratory volume in 1 sec/forced vital capacity ratio. CONCLUSIONS: We conclude that an inexpensive home rehabilitation program can improve quality of life and exercise tolerance in patients with moderate chronic obstructive pulmonary disease. Furthermore, our results indicate that exercise tolerance evaluated by cycloergometry and quality of life evaluated by the mean of the Health Status Index questionnaire are independent outcome measures of pulmonary rehabilitation.

Aged↗
PubMed1995

Exercise intolerance in chronic heart failure is not associated with impaired recovery of muscle function or submaximal exercise performance.

OBJECTIVES: This study investigated whether recovery of skeletal muscle function is impaired in patients with heart failure and whether impaired recovery is associated with abnormal submaximal systemic exercise tolerance during repeated testing. BACKGROUND: Patients with heart failure experience fatigue during daily activities. Because abnormalities of skeletal muscle play a role in their exercise intolerance, these symptoms may reflect a delay in muscle recovery and a resulting limitation in submaximal exercise tolerance. METHODS: Two protocols were used. In protocol 1, knee extensor strength and endurance, and their recovery after fatiguing exercise, were evaluated in 11 patients (mean [+/- SEM] age 62 +/- 5 years, New York Heart Association functional class 2.3 +/- 0.2, ejection fraction 24 +/- 5%) and in 10 age-matched sedentary control subjects. Protocol 2 examined the recovery of knee extensor endurance and submaximal exercise tolerance, as quantified on a self-powered treadmill, over 24 h in 18 patients (mean age 65 +/- 3 years, functional class 2.4 +/- 0.2, ejection fraction 23 +/- 3%) and in 10 control subjects. RESULTS: Peak oxygen consumption was reduced in both heart failure groups (15.4 +/- 1.4 and 15.6 +/- 1.0 ml/kg per min) compared with that in the respective control groups (23.1 +/- 2.9 and 25.6 +/- 1.0 ml/kg per min, both p < 0.05), as was muscle endurance but not muscle strength. In protocol 1, knee extensor endurance recovered more slowly in the patients than in control subjects (to 62 +/- 4% and 87 +/- 7% of the baseline value after 5 min, respectively, p < 0.05). In protocol 2, submaximal exercise tolerance was lower in the patients with heart failure than in control subjects (1,075 +/- 116 vs. 1,390 +/- 110 m), but knee extensor endurance and walking distance recovered fully by 10 and 30 min, respectively. CONCLUSIONS: Although these findings confirm earlier studies that demonstrated impaired muscle endurance in patients with heart failure, the results provide no evidence that recovery of either muscle function or submaximal exercise tolerance is delayed beyond the initial 5 to 10 min after exercise.

Aged↗
PubMed2004

Cholinergic stimulation with pyridostigmine protects against exercise induced myocardial ischaemia.

OBJECTIVE: To determine the acute effects of pyridostigmine bromide, a reversible cholinesterase inhibitor, during exercise in patients with coronary artery disease. DESIGN: Double blind, randomised, placebo controlled, crossover study. SETTING: Outpatients evaluated in an exercise test laboratory. PATIENTS: 15 patients with exercise induced myocardial ischaemia. INTERVENTIONS: Maximal cardiopulmonary exercise test on a treadmill according to an individualised ramp protocol on three days. The first day was used for adaptation to the equipment and to determine exercise tolerance and the presence of exercise induced ischaemia. On the other two days, the cardiopulmonary exercise test was performed two hours after oral administration of pyridostigmine (45 mg) or placebo. All patients were taking their usual medication during the experiments. MAIN OUTCOME MEASURES: Rate-pressure product and oxygen uptake during exercise. RESULTS: Pyridostigmine inhibited the submaximum chronotropic response (p = 0.001), delaying the onset of myocardial ischaemia, which occurred at a similar rate-pressure product (mean (SE) placebo 20.55 (1.08) mm Hg x beats/min 10(3); pyridostigmine 19.75 (1.28) mm Hg x beats/min 10(3); p = 0.27) but at a higher exercise intensity (oxygen consumption: placebo 18.6 (1.7) ml/kg/min; pyridostigmine 19.6 (1.8) ml/kg/min; p = 0.03). Also, pyridostigmine increased peak oxygen consumption (placebo 23.6 (2) ml/kg/min; pyridostigmine 24.8 (2) ml/kg/min; p = 0.01) and peak oxygen pulse (placebo 12.9 (1) ml/beat; pyridostigmine 13.6 (1) ml/beat; p = 0.02). CONCLUSIONS: Pyridostigmine improved peak exercise tolerance and inhibited the chronotropic response to submaximum exercise, increasing the intensity at which myocardial ischaemia occurred. These results suggest that pyridostigmine can protect against exercise induced myocardial ischaemia.

Aged↗
PubMed2004

Risk factors for nursing home placement following major nonemergent surgery.

PURPOSE: To determine the association between self-reported exercise tolerance and the risk of unanticipated postoperative nursing home placement in adults undergoing major surgery. METHODS: Consecutive community-dwelling adults (N = 586) referred to a medical clinic for evaluation before undergoing major nonemergent surgery at a tertiary care academic medical center were prospectively followed between 1995 and 1997. The main outcome measure was unanticipated postoperative nursing home placement. RESULTS: Overall, 12% (40/324) of patients with poor preoperative exercise tolerance (inability to walk four blocks and climb two flights of stairs without symptomatic limitation) had unanticipated nursing home placement compared with 4% (10/262) of patients with good exercise tolerance. Patient and surgical characteristics associated with nursing home placement in univariate analyses included poor preoperative exercise tolerance, increasing age, living alone, history of heart failure, taking five or more preoperative medications, longer anesthesia duration, and orthopedic surgery. Patients who were married were at lower risk. After adjusting for all other patient and surgical factors, poor preoperative exercise tolerance (odds ratio [OR] = 2.8; 95% confidence interval [CI]: 1.3 to 6.2) and serious postoperative complications (OR = 4.7; 95% CI: 2.1 to 10.5) remained associated with postoperative nursing home placement. CONCLUSION: Poor preoperative exercise tolerance was an independent predictor of unanticipated nursing home placement following major nonemergent surgery.

Aged↗
PubMed1983

Functional limitation in aortic valve disease: superiority of bicycle test to symptom-rated appraisal?

The overall functional capacity in aortic valve disease was evaluated using the New York Heart Association criteria and symptom-limited bicycle ergometry in 80 patients who underwent cardiac catheterization. The correlations between exercise performance and resting cardiac haemodynamics and clinical class were poor. Similar exercise tolerance appeared to be associated with comparable resting left ventricular (LV) performance in each haemodynamic subgroup. Limitation in exercise tolerance in aortic stenosis (n = 25), as defined by peak work-load achieved and work-pulse index, together with an inability to raise systolic blood pressure during exercise, appeared to be associated not only with a more significant reduction in LV systolic pump function and compliance but also with greater LV dilatation. A lack of correlation between exercise performance and resting LV function was seen in patients with aortic regurgitation (n = 35); and, to large extent, in those with combined lesion (n = 20). The severity of the valvular lesion was not indicated by functional limitation in any of the subgroups, although greater systolic blood pressure during exercise appeared to reflect more significant valvular leakage in the combined lesion group. It is concluded that objective tests of exercise tolerance are to be preferred in monitoring the course of the disease and the therapy provided. Aortic regurgitation appears to cause as great a limitation in exercise tolerance as does aortic stenosis alone, but may not be associated with greater deterioration in LV function at a similar level of functional limitation. Pressure overload to the LV may explain the ability of impaired LV function to reflect the limitation in exercise tolerance in cases of aortic stenosis.

Adult↗
PubMedDate not supplied

Physical activity patterns and exercise performance in cardiac transplant recipients.

BACKGROUND: Cardiac transplantation (CTX) improves exercise tolerance, but CTX recipients still achieve only 50% to 70% of normal values for exercise capacity. Among the factors suggested to explain the reduced exercise tolerance in CTX recipients is deconditioning. Little is known about the relation between physical activity patterns and exercise test responses in CTX patients. METHODS: Forty-seven CTX patients (mean age 47 +/- 12 years; mean 4.8 +/- 3.0 years after CTX) underwent maximal exercise testing and assessment of current and past physical activity patterns using a questionnaire. Energy expenditure from recreational and occupational activities over the last year and for adulthood were expressed in kcal/week and correlated with peak oxygen consumption (VO(2)), VO(2) at the ventilatory threshold, and the percentage of age-predicted peak VO(2) achieved. RESULTS: The patients reported expending a mean of approximately 1100 kcal/week in recreational activity, suggesting a moderate level of physical activity is maintained after CTX. The mean peak VO(2) achieved for the group was 17.2 +/- 5.2 mL/kg/min, corresponding to 59% +/- 14% of age-predicted exercise capacity. Significant but modest associations were observed between recreational energy expenditure during the last year and percentage of age-predicted peak VO(2) achieved (r = 0.34, P <.01), and VO(2) at the ventilatory threshold (r = 0.45, P <.01). Energy expenditure from blocks walked and stairs climbed per week was modestly associated with peak VO(2) (r = 0.36, P <.05), percentage of predicted peak VO(2) achieved (r = 0.39, P <.01), and VO(2) at the ventilatory threshold (r = 0.42, P <.01). Exercise capacity was poorly related to occupational and recreational activities when expressed as average weekly energy expended throughout adulthood. CONCLUSION: Post-CTX patients maintain a moderately active lifestyle. Measures of exercise tolerance generally are related to recent daily recreational activities in CTX patients, but these associations are modest. The many physiologic factors unique to CTX recipients likely play a more important role than deconditioning in determining exercise tolerance in these patients.

Age Factors↗
PubMed2005

Differential exercise performance on ventricular assist device support.

BACKGROUND: Ventricular assist devices (VADs) are approved for destination therapy because they improve survival in end-stage heart failure (HF). VADs are powered pneumatically or electrically. Pneumatic and electric left ventricular assist devices (LVADs) and biventricular assist devices (BiVADs) provide excellent hemodynamic support at rest, but differences in their effects on exercise tolerance are unclear. We sought to evaluate the effect of devices with varying operating parameters on exercise capacity. METHODS: Exercise physiology data obtained during maximal exercise with on-line gas-exchange analysis were collected for 38 consecutive VAD-implanted HF patients referred for exercise testing. RESULTS: Electric LVADs were implanted in 18 patients, and pneumatic LVADs in 10 patients. Percent of predicted peak exercise oxygen consumption (VO2%) was significantly greater in pneumatic LVAD patients (52.1 +/- 11.1% vs 38.2 +/- 11.3%, p < 0.05). The 10 patients implanted with a pneumatically powered LVAD were compared to 10 patients implanted with a pneumatically powered BiVAD. LVAD-supported patients had a higher VO2% (52.1 +/- 11.1% vs 36.5 +/- 17.7%, p < 0.05). CONCLUSIONS: HF patients supported with a pneumatic LVAD appear to have better exercise tolerance than those receiving an electric LVAD. Patients on LVAD support have better exercise tolerance than BiVAD-supported patients. This highlights the importance of right ventricular function to exercise tolerance in HF patients, and may have implications for future VAD design.

Adult↗
PubMed1993

Influence of angiotensin converting enzyme inhibition on exercise performance and clinical symptoms in chronic heart failure: a multicentre, double-blind, placebo-controlled trial.

One hundred and seven patients with chronic heart failure (NYHA class II to IV) stabilized on digitalis and/or diuretics, recruited from 11 centres were randomized into a double-blind, placebo-controlled study to assess the effect of 12 weeks of cilazapril therapy on exercise tolerance and clinical status. Thirty-five patients were randomized to placebo and 72 to cilazapril at a starting dose of 1 mg daily; titration to cilazapril 2.5 mg at week 4 and 5 mg at week 8 (or matching placebo) was carried out in patients who did not improve clinically. Demographic characteristics, including exercise test duration increased from 402 s (+/- 17 SEM) at baseline to 462 s (+/- 19 SEM) at week 12 for the cilazapril group (+15%) and from 405 s (+/- 23 SEM) at baseline to 408 s (+/- 30 SEM) at week 12 in patients on placebo (+1%) (P < 0.001). In the placebo group, patients able to exercise for more than 6 min at baseline showed an increase in exercise duration at week 12 while those able to exercise for up to 6 min at baseline showed a decrease (P = ns). In contrast, cilazapril-treated patients showed an increase in exercise tolerance regardless of baseline exercise test duration; patients with the most impaired exercise tolerance at baseline showed a greater improvement than patients with mildly impaired baseline exercise tolerance (P < 0.05 vs placebo). NYHA class improved by at least one grade in 51% of the cilazapril group vs 32% in the placebo group (P = ns). At the end of the trial, 15% of the patients were non-responders on cilazapril vs 41% on placebo (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗