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PubMed1981

Effects of breathing retraining in patients with chronic obstructive pulmonary disease.

Subjects with severe chronic obstructive pulmonary disease (COPD) were studied to evaluate the effects of breathing retraining (BRT) on exercise tolerance. Twenty-two subjects exercised on a treadmill three times weekly for six weeks. Twelve of the subjects (controls) then exercised for three more weeks; the other ten subjects received three more weeks of exercise reconditioning plus BRT. Results of routine pulmonary function and exercise tests were similar in both groups at the beginning of the study and after six weeks of exercise. However, in the last three weeks of the study, increments in exercise performance were significantly greater in the BRT subjects than in controls (P less than .002). Following BRT, respiratory rate during exercise decreased (P less than .005) and tidal volume and PaO2 during exercise increased (P less than .05). Thus, these data suggest that BRT increases exercise performance in subjects with severe COPD.

Breathing Exercises↗

PubMed1990

Prolonged hypoxemia after 10 min walking exercise in aged patients with chronic obstructive pulmonary disease.

Although the behavior and factors of exercise tolerance have been studied during exercise in patients with chronic obstructive pulmonary disease (COPD), little attention has been paid to the after-effects of such activity. Arterial oxygen saturation (SaO2) was monitored during and after a 10 min walking exercise in aged patients with COPD. Neither baseline SaO2 nor mean SaO2 during exercise correlated to the 10 min walking distance. However, the recovery time of SaO2 to the baseline value shows significant correlation to the 10 min walking distance. Careful attention should be paid to prolonged hypoxemia after exercise in severe cases of COPD.

Aged↗

PubMed2002

The role of dobutamine stress echocardiography in idiopathic dilated cardiomyopathy.

In patients with chronic heart failure, myocardial contractile responsiveness to dobutamine is diminished as a result of beta-receptor desensitization due to chronic adrenergic activation. Changes in beta-receptor effector mechanisms are more marked in idiopathic dilated cardiomyopathy (IDCM) than in ischemic dilated cardiomyopathy. As the magnitude of the dobutamine effect is proportional to the severity of left ventricular systolic dysfunction, the heterogeneous cardiotonic effects of dobutamine in IDCM may represent different evolutive stages of a progressive disease process. On the basis of this pathophysiologic background, some studies were undertaken to investigate the prognostic and functional implications of dobutamine stress echocardiography (DSE) in IDCM. Prognostic studies consistently suggest that myocardial response to dobutamine is related to the clinical outcome. However, the limited number of patients and events in the individual studies are important limitations. Moreover, the impact of beta-blockers on the potential ability of DSE to predict the prognosis needs to be assessed. A few studies also suggest that changes in left ventricular systolic function parameters following dobutamine infusion are related to exercise tolerance, as assessed by peak exercise oxygen consumption and functional recovery of the failing myocardium. The data suggest that DSE is a promising method, which may improve the risk stratification process in patients with IDCM and provide further insights into the pathophysiologic mechanisms underlying progressive systolic pump dysfunction and exercise intolerance. Further studies are however needed to define the role of DSE in IDCM.

Cardiomyopathy, Dilated↗

PubMed1987

The role of exercise testing in pulmonary diagnosis.

Exercise stresses the body's functional reserves that allow for the increased metabolic work and gas transport necessary for the efficient production of energy with physical activity or stress. Disease that reduces reserve in the gas transport organs will produce exertional symptoms not present at rest. Exercise testing has been well established in the evaluation of healthy persons and cardiac patients who are limited by cardiac or peripheral muscle function. For patients with lung disease, however, whose exercise performance is limited by reduced ventilatory capacity and disordered gas exchange, principles of exercise testing (and training) are different. In the evaluation of pulmonary patients, exercise testing can be used to measure exercise tolerance, assess the limitation to exercise in patients with unexplained dyspnea, evaluate patients for respiratory disability, assess blood gas changes with exercise, and detect exercise-induced asthma. Nevertheless, our understanding of the role of exercise in pulmonary diagnosis is at an early stage of development and much needs to be learned about the practical applications of exercise testing in the diagnosis, staging, and serial evaluation of pulmonary diseases.

Asthma, Exercise-Induced↗

PubMed1984

Left ventricular ejection times during exercise testing with scintigraphy. Their use in the detection of ischemic heart disease.

Left ventricular ejection times ( LVETs ) were obtained in a group of 20 control subjects (group 1) during maximal treadmill exercise testing, using a Bruce protocol, and in conjunction with myocardial scintigraphy. Heart rates (HRs) and LVETs were recorded during standing rest, each minute of exercise, and for eight minutes in the postexercise period. A linear regression equation was constructed and separate correction factors of 1.04 X HR + observed LVET (correlation coefficient, -.86) for the exercise period and 0.73 X HR + LVET (correlation coefficient, -.71) for the postexercise period were derived. The LVETs were also recorded in 31 subjects with positive ECGs and defects on myocardial scanning with thallous chloride TL201 (group 2) during a similar exercise protocol. Comparison of groups 1 and 2 disclosed that the former had a higher HR and shorter LVET than the latter at peak effort (consonant with the significantly longer duration of exercise achieved by the control subjects). The LVETs in group 1 remained significantly shorter than that of group 2 through the fifth minute postexercise. In the postexercise period, the LVET indexes were significantly shorter in group 1 than group 2 at 1, 3, and 5 minutes. Subjects with presumptive coronary disease (positive ECG and defects on thallium 201 scanning) not only have a decreased exercise tolerance and HR, but after exercise, their ejection times are substantially longer than in normal subjects. This may be attributed to a slower rate of ejection in patients with coronary disease when venous pooling on quiet standing after exercise delivers a smaller volume to the heart. In normal subjects, the lesser volume may be ejected more rapidly.

Adult↗

PubMed1980

Strenuous physical activity, treadmill exercise test performance and plasma high-density lipoprotein cholesterol. The Lipid Research Clinics Program Prevalence Study.

During the Lipid Research Clinics North American Prevalence Study, plasma lipoprotien determinations and treadmill exercise testing were performed on 2319 white men and 2067 white women ages 20 years or older randomly selected from population surveys by nine clinics in the U.S. and Canada. Before exercise testing, participants were asked if they performed any strenuous physical activity on a regular basis. Data were analyzed to determine the relationship of plasma high-density lipoprotein (HDL) cholesterol to treadmill exercise test performance and a self-report of strenuous activity. Neither treadmill exercise test duration nor heart rate response to submaximal exercise was significantly related to HDL cholesterol levels for either men or women. However, participants who reported some strenuous physical activity generally had higher HDL cholesterol levels than those who reported none, and the more active men ages 30-49 years and active women ages 20-39 had significantly higher values (p < 0.05). When HDL cholesterol was adjusted for age, body mass index, alcohol use, cigarette smoking and interclinic population variation, more active men (47.1 vs 45.2 mg/dl; p = 0.0001) and more active women (59.6 vs 57.7 mg/dl; p = 0.02) had higher HDL cholesterol levels than their sedentary counterparts. Thus, the association between HDL cholesterol and reported physical activity was, at least in part, independent of other factors that influence HDL cholesterol concentration, but was not associated with exercise tolerance as determined by treadmill exercise testing.

Adult↗

PubMed1994

[Should all cases of aortic valve stenosis be surgically treated?].

Aortic stenosis is a condition in which progression accelerates with the onset of warning symptoms such as angina pectoris, syncope and heart failure. Surgery must be scheduled as quickly as possible in all such symptomatic patients, even in the presence of concomitant coronary disease, or of left ventricular failure. Aortic valve surgery is possible in the elderly, with a higher operative risk, but with the benefit of a symptomatic improvement identical to that seen in younger individuals, and a prolongation of life expectancy. Surgery is often considered in asymptomatic patients because of the fear of sudden death. In actual fact, sudden death not preceded by other symptoms is rare and the aim of surveillance must be to identify high-risk patients to whom surgery may be offered: poor exercise tolerance in a cautiously administered exercise test, abnormal ventricular function by echocardiography, or the existence of arrhythmias, which are also a severity factor, whether atrial or ventricular. The number of completely asymptomatic cases among patients with tight aortic stenosis is relatively slight, having been evaluated at 5%. It is in these asymptomatic patients, when they are young, that it is possible to delay surgery until the onset of a first symptom.

Age Factors↗

PubMedDate not supplied

Cardiovascular disease in women: implications of hormone replacement therapy.

Arterial dysfunction and disease affect a majority of women during their life time. Ovarian hormones inhibit the development of atherosclerosis and play an integral role in the maintenance of normal arterial function. Estrogens act in the liver to improve and maintain lipid profiles and also act in the walls of arteries and in cardiac myocytes to maintain function and prevent disease. Death from cardiovascular disease is reduced in women receiving estrogen replacement therapy (ERT). Ten-year follow-up studies of women with advanced coronary artery disease (CAD) show a marked reduction in fatalities among the women receiving estrogens compared with untreated women. Sublingual estradiol-17 beta compared with placebo results in improved exercise tolerance and reduced ischemia during exercise in women with CAD. Estradiol-17 beta infused into the coronary arteries in women with CAD leads to improved arterial function. Estrogen deficiency has been reported in women with angina pectoris who have normal coronary arteries, and these women respond to estrogen treatment. HRT implies the use of ERT with the addition of a progestin. Progestins oppose the actions of estrogens. Counter-effects of lipid metabolism appear to be minimal with progestins currently in use. Oppositional effects of progestins on hemodynamic actions of estrogens may be significant, as progestins appear to induce vasoconstriction of estrogenized vessels.

Arteriosclerosis↗

PubMed1996

[ST segment depression during recovery after treadmill exercise test in stable patients with previous myocardial infarction].

BACKGROUND: The significance of exercise-induced ST segment depression is well known while limited data are available on the clinical/prognostic power of ST depression occurring only during recovery. Aim of the study was to clarify the clinical/prognostic value of "recovery only" ST depression in stable patients late from myocardial infarction (AMI) and to determine whether the addition of recovery data to exercise parameters improves the interpretation of exercise test. METHODS: From a population of 766 consecutive patients (mean age: 57.2 +/- 8.6 yrs.; male: 89%) who underwent a Bruce Treadmill test at least 1 year after a Q wave AMI and whose exercise data were prospectively entered in the database of our Institution, 4 different Groups were identified: 1) 99 patients with a negative exercise test; 2) 53 patients with "exercise only" ST depression; 3) 140 patients with "exercise and recovery" ST depression; 4) 31 patients with "recovery only" ST depression. The main clinical and exercise data and a cardiac follow-up (average mean length: 1530 +/- 600 day) were evaluated by one-way analysis of variance, Bonferroni T-test, chi-square, relative risk (RR) with 95% confidence intervals (CI), Kaplan-Meler method and log-rank. RESULTS: Baseline clinical parameters were similar in the 4 Groups except for older age in Group 3 compared to Group 2 (< 0.05) and higher prevalence of anterior AMI in Group 4 compared to others (= 0.004). Patients with exercise and recovery ST depression or with "recovery only" ST depression had significantly less exercise tolerance than patients with negative exercise test or "exercise only" ST depression [exercise duration (< 0.05, Group 1 vs. 3, vs. 4; Group 2 vs. 3), peak rate pressure product (< 0.05), maximal heart rate (< 0.05; Group 1 vs. 2; vs. 3; vs. 4)]. Exercise-induced ST depression was higher and angina was significantly more frequent in patients with exercise and recovery ST depression as well as an high Mark's risk score (< 0.001). Only patients with exercise and recovery ST depression demonstrated significantly higher risk of overall mortality (RR: 1.35, CI: 1.04-1.74), unstable angina (RR: 1.34, CI: 1.09-1.65) or revascularisation procedures (RR: 1.51, CI: 1.25-1.83). Relative risk of patients with "recovery only" ST depression was similar to that of subjects with "exercise only" ST depression. CONCLUSIONS: In stable patients with old Q wave AMI, "recovery only" ST depression is rate, but does represent a true sign of ischemia. It could be associated with indirect indexes of worse ventricular function. The prognostical power of "recovery only" ST depression is mild, although similar to that of "exercise only" ST depression. Moreover the presence of ST depression not only during exercise but also during the recovery phase identifies patients with more severe prognosis. Therefore the inclusion of findings from the recovery phase in the analysis of the exercise test could increase the predictive power of the test itself.

Aged↗

PubMed2006

Long term effects of bosentan treatment in adult patients with pulmonary arterial hypertension related to congenital heart disease (Eisenmenger physiology): safety, tolerability, clinical, and haemodynamic effect.

BACKGROUND: Oral bosentan is an established treatment for pulmonary arterial hypertension (PAH). OBJECTIVE: To evaluate safety, tolerability, and clinical and haemodynamic effects of bosentan in patients with PAH related to congenital heart disease (CHD). PATIENTS: 22 patients with CHD related PAH (8 men, 14 women, mean (SD) age 38 (10) years) were treated with oral bosentan (62.5 mg x 2/day for the first 4 weeks and then 125 mg x 2/day). MAIN OUTCOME MEASURES: Clinical status, liver enzymes, World Health Organisation (WHO) functional class, resting oxygen saturations and 6-min walk test (6MWT) were assessed at baseline and at 1, 3, 6, and 12 months. Haemodynamic evaluation with cardiac catheterisation was performed at baseline and at 12 month follow-up. RESULTS: 12 patients had ventricular septal defect, 5 atrioventricular canal, 4 single ventricle, and 1 atrial septal defect. All patients tolerated bosentan well. No major side effects were seen. After a year of treatment, an improvement was seen in WHO functional class (2.5 (0.7) v 3.1 (0.7); p<0.05), oxygen saturation at rest (87 (6%) v 81 (9); p<0.001), heart rate at rest (81 (10) v 87 (14) bpm; p<0.05), distance travelled in the 6MWT (394 (73) v 320 (108) m; p<0.001), oxygen saturation at the end of the 6MWT (71 (14) v 63 (17%); p<0.05), Borg index (5.3 (1.8) v 6.5 (1.3); p<0.001), pulmonary vascular resistances index (14 (9) v 22 (12) WU m(2); p<0.001), systemic vascular resistances index (23 (11) v 27 (10) WU.m(2); p<0.01), pulmonary vascular resistances index/systemic vascular resistances index (0.6 (0.5) v 0.9 (0.6); p<0.05); pulmonary (4.0 (1.3) v 2.8 (0.9) l/min/m2; p<0.001) and systemic cardiac output (4.2 (1.4) v 3.4 (1.1) l/min/m2; p<0.05). CONCLUSIONS: Bosentan was safe and well tolerated in adults with CHD related PAH during 12 months of treatment. Clinical status, exercise tolerance, and pulmonary haemodynamics improved considerably.

Administration, Oral↗

PubMed2001

Exercise intolerance in mitochondrial myopathy is not related to lactic acidosis.

In a double-blinded, placebo-controlled, crossover study in seven mitochondrial myopathy patients (MM), we investigated whether lowering of lactate with dichloroacetate (DCA) can improve exercise tolerance and oxidative capacity in MM. DCA lowered plasma lactate at rest and during exercise (from 10.5 +/- 2.0 to 5.0 +/- 1.6 mM; p = 0.005) but did not improve maximal work load or VO2 in cycle exercise or phosphorous magnetic resonance spectroscopy (31P-MRS)-assessed indices of muscle oxidative metabolism. This indicates that lactate acidosis is not the primary cause of exercise intolerance in MM.

Acidosis, Lactic↗

PubMed2005

Aging and heart failure--similar syndromes of exercise intolerance? Implications for exercise-based interventions.

A classic hallmark of chronic heart failure (CHF) is exercise intolerance; however, the extent of exercise limitation is not correlated with the degree of left ventricular dysfunction. Over the past 2 decades it has become more and more evident that peripheral factors, such as skeletal muscle dysfunction, ventilatory abnormalities, and endothelial dysfunction, contribute the greater part to the limitation of exercise capacity. The molecular and pathophysiological changes observed in these organ systems are not always specific to the underlying CHF but rather represent a common pathway that is activated in several chronic disease processes, including severe chronic obstructive pulmonary disease, cancer, and in the normal aging process. A major contributing factor for skeletal muscle catabolism (i.e. elevated cytokine expression in the skeletal muscle) can be found in both normal healthy aging and in heart failure patients. It is reasonable to assume that the overlap of aging and CHF-associated changes in the skeletal muscle partially explains the disabling consequences of the CHF syndrome among elderly patients (nearly 80% of all patients hospitalized for CHF are >65 years old). Peripheral alterations in CHF are often not adequately treated in routine clinical care since standard pharmacological therapy is still focused on the cardiac function and neurohormonal alteration. Exercise training is a guideline-oriented adjuvant therapy with well-documented beneficial effects on exercise tolerance, skeletal muscle function, endothelial function, and respiration. In this review, the effects of exercise in aging and in CHF are compared and the parallel mechanisms are explored.

Aged↗

PubMed2006

L-carnitine as an ergogenic aid for patients with chronic obstructive pulmonary disease submitted to whole-body and respiratory muscle training programs.

The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease (COPD) patients. Sixteen COPD patients (66 +/- 7 years) were randomly assigned to L-carnitine (CG) or placebo group (PG) that received either L-carnitine or saline solution (2 g/day, orally) for 6 weeks (forced expiratory volume on first second was 38 +/- 16 and 36 +/- 12%, respectively). Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions, with 3 sets of 10 loaded inspirations (40%) at maximal inspiratory pressure. Nutritional status, exercise tolerance on a treadmill and six-minute walking test, blood lactate, heart rate, blood pressure, and respiratory muscle strength were determined as baseline and on day 42. Maximal capacity in the incremental exercise test was significantly improved in both groups (P < 0.05). Blood lactate, blood pressure, oxygen saturation, and heart rate at identical exercise levels were lower in CG after training (P < 0.05). Inspiratory muscle strength and walking test tolerance were significantly improved in both groups, but the gains of CG were significantly higher than those of PG (40 +/- 14 vs 14 +/- 5 cmH2O, and 87 +/- 30 vs 34 +/- 29 m, respectively; P < 0.05). Blood lactate concentration was significantly lower in CG than in PG (1.6 +/- 0.7 vs 2.3 +/- 0.7 mM, P < 0.05). The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients, as well as reduce lactate production.

Aged↗

PubMed1995

Coenzyme Q10 as an adjunctive in the treatment of chronic congestive heart failure. The Q10 Study Group.

Seventy-nine patients with stable chronic congestive heart failure were randomized into a double-blind, crossover placebo controlled study with 3-month treatment periods, where either 100 mg coenzyme Q10 (CoQ10) or placebo was added to conventional therapy. Mean patient age was 61 +/- 10 years, ejection fraction at rest was 22% +/- 10%, and maximal exercise tolerance was 91 +/- 30 W. The follow-up examinations included ejection fraction (primary objective), exercise test, and quality of life questions. Ejection fraction at rest, during a slight volume load, and during a submaximal supine exercise increased slightly compared with placebo: 24% +/- 12% versus 23% +/- 12% (NS), 25% +/- 13% versus 23% +/- 12% (P < .05), and 23% +/- 11% versus 22% +/- 11% (NS). Maximal exercise capacity increased from 94 +/- 31 W during the placebo period to 100 +/- 34 W during the CoQ10 period (P < .05). Total score for the quality of life assessment increased significantly from 107 +/- 23 during the placebo period to 113 +/- 22 during the CoQ10 period (P < .05). The results indicate that oral long-term treatment with 100 mg CoQ10 in patients with congestive heart failure only slightly improves maximal exercise capacity and the quality of life and that the clinical importance of this needs to be further evaluated.

Aged↗

PubMed1999

Compassionate use of continuous prostacyclin in the management of secondary pulmonary hypertension: a case series.

BACKGROUND: Treatment of patients with secondary pulmonary hypertension has been unsatisfactory. OBJECTIVE: To describe exercise capacity, functional class, and hemodynamic variables after long-term intravenous infusion of prostacyclin in patients with secondary pulmonary hypertension. DESIGN: Case series. SETTING: Academic referral center. PATIENTS: 33 patients with secondary, precapillary pulmonary hypertension (New York Heart Association class III or IV). INTERVENTION: Continuous intravenous prostacyclin administered by portable infusion pump on a compassionate-use basis. MEASUREMENTS: Functional class, treadmill time, and hemodynamic variables. RESULTS: Patients were followed for an average of 12.7 +/- 5.6 months. Exercise tolerance and New York Heart Association class improved in each patient. The duration of treadmill exercise increased from 186 seconds to 491 seconds, an increase of 305 seconds (95% CI, 194 to 417 seconds; P < 0.001). Mean pulmonary artery pressure decreased from 60 mm Hg to 46 mm Hg, a decrease of 14 mm Hg (CI, 9 to 19 mm Hg; P < 0.001). Cardiac output increased from 3.90 L/min to 6.30 L/min, an increase of 2.40 L/min (CI, 1.56 to 3.25 L/min; P < 0.001). The pulmonary vascular resistance decreased from 1143 dynes x s/cm5 to 575 dynes x s/cm5, a decrease of 567 dynes x s/cm5 (CI, 407 to 727 dynes x s/cm5; P < 0.001). Patients with collagen vascular disease, congenital heart disease, and portopulmonary hypertension were analyzed with other patients and separately. All groups had a statistically significant reduction in mean pulmonary artery pressure and a statistically significant increase in cardiac output. CONCLUSION: Intravenous prostacyclin may be effective in the treatment of patients with certain types of secondary pulmonary hypertension.

Antihypertensive Agents↗

PubMedDate not supplied

Nocturnal mechanical ventilation improves exercise capacity in kyphoscoliotic patients with respiratory impairment.

BACKGROUND: Patients with severe kyphoscoliosis, with or without stable respiratory failure, frequently experience oxyhaemoglobin desaturation during sleep, exercise, or both. Nasal Intermittent Positive Pressure Ventilation (NIPPV) applied during sleep has been demonstrated to be able to control nocturnal desaturations and also improve diurnal respiratory failure, if this is present, in this group of patients. The aim of this study was to evaluate the effect of a seven-day treatment with nocturnal NIPPV on exercise tolerance in a group of 6 patients with severe kyphoscoliosis and significant nocturnal and exercise-induced oxyhaemoglobin desaturation. METHODS: NIPPV was applied each night for a week by means of a volume cycled pressure ventilator set in assisted/controlled mode. In each patient lung function, daytime arterial blood gas analysis, overnight non invasive recording of arterial saturation, and 6-minutes walking test were carried out initially and at the end of the NIPPV course. RESULTS: During nocturnal NIPPV, as compared to baseline, the percent of night time spent below 90% of oxyhaemoglobin saturation significantly fell from 20 +/- 12.8 to 2.3 +/- 1.9 (Student t-test: p = 0.017). The 6-minute walking distance significantly increased from 244.7 +/- 132.2 to 340 +/- 122.3 m (p = 0.0097). Spirometry, daytime arterial blood gas analysis, and exercise-induced oxyhaemoglobin desaturation were unaffected by treatment. CONCLUSION: A one-week course of treatment with nocturnal NIPPV improves exercise capacity in patients with severe kyphoscoliosis.

Adult↗

PubMed1993

Transdermal nitroglycerin reduces the frequency of anginal attacks but fails to prevent silent ischemia.

OBJECTIVES: The aim of this study was to objectively evaluate the effects of intermittent administration of transdermal nitroglycerin on effort tolerance, frequency of anginal attacks and presence of silent ischemic events that occur during normal daily activities. BACKGROUND: Previous studies have shown that transdermal nitroglycerin patches reduce the incidence of anginal attacks and improve exercise capacity when given intermittently. However, no carefully controlled studies are available on the effects of these preparations (and their dosing schedule) on the occurrence of "silent" ischemic events during unrestricted daily activities. METHODS: Twelve men with chronic stable angina, a positive exercise test result and significant coronary artery disease completed a randomized, double-blind, placebo-controlled trial in which patches were worn either continuously or with overnight (8 h) removal. The effects of treatment were objectively assessed by both treadmill exercise testing and 24-h ambulatory electrocardiographic monitoring. RESULTS: Only the intermittent dosing schedule afforded a small but significant improvement in exercise tolerance and prolonged exercise duration and time to ST segment depression. The frequency of anginal attacks was also reduced by both the continuous and intermittent treatment, but the effects on symptoms were not paralleled by a concomitant reduction in ischemic episodes recorded during ambulatory monitoring. CONCLUSIONS: The results indicate that when used as monotherapy, intermittent transdermal nitroglycerin preparations lessen symptoms but are ineffective for the long-term prophylaxis of silent myocardial ischemia.

Administration, Cutaneous↗

PubMed2005

Left atrial volumetric remodeling is predictive of functional capacity in nonobstructive hypertrophic cardiomyopathy.

BACKGROUND: The left atrium is afterload sensitive, responding to immediate changes in left ventricular (LV) diastolic pressure, and left atrial volumetric remodeling has been reported in conditions associated with abnormal diastolic function. We examined the relationship between left atrial volumetric remodeling and objective measures of exercise capacity in patients with nonobstructive hypertrophic cardiomyopathy (HCM). METHODS: We compared LA volume indices, other 2-dimensional and Doppler echocardiographic parameters, invasive hemodynamic measures, and magnetic resonance imaging (MRI)-derived LV mass with exercise duration, maximal oxygen uptake (MV* O2), anaerobic threshold (AT), and ventilatory efficiency (VE/V* CO2 slope) in 43 patients with nonobstructive HCM. Patients underwent cardiac catheterization within 48 hours and metabolic stress testing within 1 week of their echocardiogram and MRI examinations. RESULTS: Left atrial volume at end-ventricular systole (LA max) and end-atrial emptying (LA min) correlated with MV* O2 (r = -0.39, P < .01 for both), AT (r = -0.42, r = -0.39, respectively, P < .01 for both), and VE/V* CO2 slope (r = 0.45, P = .003; r = 0.41, P = .008). Patients with an LA max > or =33 mL/m2 had significantly lower MV* O2 (P = .025) and AT levels (P = .017) and higher VE/V* CO2 slope levels (P = .004) as compared with patients with a smaller LA size. In multivariate analysis, MRI-determined LV mass, which was not a univariate correlate of exercise tolerance, provided additional effect when combined with LA volume index. CONCLUSIONS: Left atrial volumetric remodeling predicts exercise capacity in nonobstructive HCM and may reflect chronic LV diastolic burden. This simple noninvasive measure of LA size may provide a long-term indication of the effects of chronically elevated filling pressures in patients with HCM and further studies testing its prognostic value are necessary.

Adult↗