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PubMed2002

[Long-term effects of rehabilitation of an outpatient "heart group". A case control study].

The effects of an outhospital cardiac rehabilitation program in "heart groups" (HG) are studied in a case-control design. The control group (KG) was collected by match-pairing from 12,560 cases of a rehabilitation clinic fitting in the relevant criteria to those of members of the HG. Patients of both groups (n = 75/group) after myocardial infarction and CABG were followed up over 7.5 years. There was no significant difference in risk factor modification. Exercise tolerance improved significantly in the HG by increasing maximum work capacity by 50% in spite of a mean age of 60 years at the beginning. Members of HG had significantly lesser cardiac complaints and lower need for cardiac medication. Cardiac morbidity was reduced by 54% and costs for medical care were lowered by 47% in HG. Although effects of secondary prevention on reducing risk factors were still insufficient, exercise tolerance in higher age and quality of life were improved, reduction in medication and in the morbidity saved costs for the health system.

Case-Control Studies↗

PubMed2001

Doppler myocardial imaging in patients with heart failure receiving biventricular pacing treatment.

BACKGROUND: In patients with heart failure, biventricular pacing (BIV) improves left ventricular (LV) performance by counteracting LV unsynchronized contraction caused by the presence of left bundle branch block (LBBB). However, no data are yet available on regional long-axis function in patients with LBBB or on BIV effectiveness in improving such a function in patients with heart failure and LBBB. METHODS AND RESULTS: We studied with standard 2D echocardiography and tissue Doppler imaging (TDI) 21 nonischemic patients in New York Heart Association (NYHA) class III-IV, with LBBB and QRS >/=120 ms, receiving BIV. To assess long-axis function, TDI qualitative analysis at the basal level of each LV wall was performed in M-mode color and pulsed wave Doppler modalities before and after BIV. By analysis of the interventricular septum, the inferior, posterior, lateral, and anterior walls, of 105 basal segments, the following electromechanical patterns were identified: normal (pattern I), mildly unsynchronized (pattern IIA), severely unsynchronized (pattern IIB), reversed early in systole (pattern IIIA), reversed late in systole (pattern IIIB), and reversed throughout all the systole (pattern IV). After BIV, (1) 49 (46.7%) of 105 segments showed unsynchronized contraction of the same degree as before; (2) 36 (34.3%) of 105 and 20 (19%) of 105 showed unsynchronized contraction of lesser and greater degree, respectively, than before; and (3) a preexcitation pattern was found in 11 (10.5%) of 105, but no segment with pattern IV was observed. According to TDI analysis, patients were divided into group 1 (10 of 21), with less severe LV asynchrony than before BIV, and group 2 (11 of 21), with no change or more severe LV asynchrony than before BIV. In group 1, (1) the LV ejection fraction increased significantly (P =.01); (2) the exercise tolerance, expressed as time and work capacity on the bicycle stress testing, increased significantly (P =.01, P =.003, respectively); (3) the 6-minute walked distance increased significantly (P =.01); and (4) the NYHA class decreased significantly (P =.003). In group 2, no significant differences were found either in LV ejection fraction, in NYHA class, or in exercise tolerance data (P = not significant for all). Conversely, the QRS narrowing was significant in both groups (P =.003 in group 1 and P =.01 in group 2). CONCLUSIONS: TDI is useful in assessing the severity of LV asynchrony in patients with LBBB with heart failure as well as in evaluating the pacing effects on long-axis function in these patients. BIV reduced unsynchronized and/or dyskinetic contraction in at least one third of the LV basal segments, whereas it induced preexcitation in approximately 10%. Such changes were responsible for better LV synchrony in approximately one half of patients. After BIV, LV performance improved significantly in patients with better LV synchrony evaluated by TDI, whereas the QRS narrowing was not predictive of this functional improvement.

Bundle-Branch Block↗

PubMed1982

Drug-induced conditioning in congestive heart failure.

Continuous 72-hour infusions of dobutamine reportedly effect sustained clinical improvement in patients with congestive heart failure. This study was designed to determine if shorter, more frequent infusions, delivered in an outpatient setting, elicit a similar response. Twenty-six patients with moderately severe congestive heart failure were randomized, 11 into a control group and 15 into a dobutamine treatment group. Baseline data were collected for 4 weeks in each group. Thereafter, the dobutamine treatment group received 4-hour infusions of dobutamine weekly for 24 weeks. Systolic time intervals, echocardiography, cardiac index and treadmill exercise tolerance were used to follow the progress of the control and dobutamine treatment groups. The ratio of preejection period to left ventricular ejection time and the cardiac index did not change significantly in either group. The velocity of circumferential fiber shortening and the percent change in the minor axis of the left ventricle during systole improved modestly (p less than 0.05) above baseline in the dobutamine group after 14 weeks of treatment and above the corresponding control values (p less than 0.05) after 22 weeks. Exercise tolerance (duration) improved 25--51% (all p less than 0.05) above baseline in the dobutamine group compared with 10--17% (all p greater than 0.05 vs baseline) in the control group. Heart rate at maximal exercise did not change significantly from baseline for either group and did not differ significantly between the two groups. Functional classification improved in 12 of 15 dobutamine treatment patients and in only two of 11 control patients (p less than 0.05). In our patients with congestive heart failure, weekly 4-hour dobutamine infusions did not elicit a major change in resting left ventricular function; however, exercise performance and clinical status improved considerably.

Adult↗

PubMed1988

Social fate and long-term survival of patients with a recent myocardial infarction, after cardiac rehabilitation.

The aim of this study was to assess the social fate (work resumption) and long-term (four years) survival in 141 patients who completed a cardiac rehabilitation programme after a recent myocardial infarction. Out of the 100 patients who had been working up to recently before the myocardial infarction, 58 resumed their work. Of the predischarge evaluation (clinical data, resting radionuclide ventriculography, bicycle ergometry and 24-h ambulatory ECG monitoring) and bicycle ergometry after the rehabilitation, the only significant predictor of work resumption was a better exercise tolerance at discharge (P less than 0.02). Work was resumed by 68% of white-collar workers and by 52% of blue-collar workers. The four-year cardiac mortality in patients who completed the rehabilitation was 8.5% (N = 12). Four patients died during the first year. Clinical, ventriculographic and ergometric variables collected at hospital discharge, which were related to left ventricular dysfunction, were predictive of survival, while ventricular arrhythmias and markers of myocardial ischaemia were less predictive. The exercise testing performed after the rehabilitation programme was not useful for risk assessment. It is concluded that markers of left-ventricular dysfunction are predictive of a poor outcome; however, due to the low risk of patients who were referred to our rehabilitation unit and completed the rehabilitation programme, it seems reasonable for return to work to be based primarily on clinical information, exercise tolerance, and on psychological and social grounds. An additional extensive cardiological evaluation should be individually tailored for patients with specific symptoms.

Adult↗

PubMedDate not supplied

Gender differences in psychosocial profile at entry into cardiac rehabilitation.

PURPOSE: To find out in a sample of coronary patients at entry into a cardiac rehabilitation program, whether women report a lower level of physical functioning and a higher degree of psychosocial impairment than men. METHODS: One hundred and nine male and 122 female patients matched for age with a diagnosis of myocardial infarction, coronary artery bypass grafting, or coronary angioplasty were assessed at entry into a multidisciplinary outpatient rehabilitation program. Information was retrieved from hospital records, a semistructured interview, and several psychological questionnaires. Variables of physical functioning included perceived exercise tolerance, functional complaints, psychosomatic complaints, and sleeping disturbances. Variables of psychosocial impairment included anxiety, depression, vital exhaustion, well-being, feelings of being disabled, displeasure, and social inhibition. RESULTS: At program entry, there were no significant differences in age, coronary risk factors, coronary incident, or medication between genders. However, women reported significantly lower perceived exercise tolerance and significantly more functional and psychosomatic complaints. Moreover, women were significantly more anxious and scored significantly higher on social inhibition and vital exhaustion than men. CONCLUSIONS: At entry into rehabilitation, women in this sample report a higher degree of psychosocial impairment and a lower level of physical functioning than men. Women's significantly higher scores on social inhibition and vital exhaustion might partly explain their reported higher drop-out and lower adherence rates in cardiac rehabilitation.

Chi-Square Distribution↗

PubMed1992

[Amiodarone in heart insufficiency].

The purpose of this study was to analyse the effects of amiodarone on the treatment of cardiac failure. The effects of 200 mg/day of amiodarone were assessed in 18 patients with a history of cardiac failure. Functional class, heart rate, blood pressure, left ventricular ejection fraction, heart size, treadmill exercise tolerance and electrocardiogram were assessed before and eight weeks after the use of amiodarone, and the side effects were monitored. In 18 patients receiving amiodarone, the functional class and heart rate decreased significantly (p < 0.05) from 2.7 +/- 0.4 to 1.2 +/- 0.4 and 103 +/- 15 to 69 +/- 8.5 beats/min respectively. The ejection fraction and the exercise tolerance increased significantly (p < 0.05) from 29.2 +/- 5.5% to 41.5% and from 379.8 +/- 271 sec to 897.8 +/- 350.8 sec respectively. The incidence of atrial and ventricular arrhythmias decreased significantly and no side effects were observed. Amiodarone appears to produce benefits in patients with cardiac failure with atrial and ventricular arrhythmias.

Amiodarone↗

PubMed2005

Exercise training and inspiratory muscle training in patients with bronchiectasis.

BACKGROUND: Bronchiectasis is a chronic suppurative lung disease often characterised by airflow obstruction and hyperinflation, and leading to decreased exercise tolerance and reduced health status. The role of pulmonary rehabilitation (PR) and inspiratory muscle training (IMT) has not been investigated in this group of patients. METHODS: Thirty two patients with idiopathic bronchiectasis were randomly allocated to one of three groups: PR plus sham IMT (PR-SHAM), PR plus targeted IMT (PR-IMT), or control. All patients (except the control group) underwent an 8 week training programme of either PR or PR plus targeted IMT. Exercise training during PR was performed three times weekly at 80% of the peak heart rate. IMT was performed at home for 15 minutes twice daily over the 8 week period. RESULTS: PR-SHAM and PR-IMT resulted in significant increases in the incremental shuttle walking test of 96.7 metres (95% confidence interval (CI) 59.6 to 133.7) and 124.5 metres (95% CI 63.2 to 185.9), respectively, and in endurance exercise capacity of 174.9% (95% CI 34.7 to 426.1) and 205.7% (95% CI 31.6 to 310.6). There were no statistically significant differences in the improvements in exercise between the two groups. Significant improvements in inspiratory muscle strength were also observed both in the PR-IMT group (21.4 cm H2O increase, 95% CI 9.3 to 33.4; p = 0.008) and the PR-SHAM group (12.0 cm H2O increase, 95% CI 1.1 to 22.9; p = 0.04), the magnitude of which were also similar (p = 0.220). Improvements in exercise capacity were maintained in the PR-IMT group 3 months after training, but not in the PR-SHAM group. CONCLUSION: PR is effective in improving exercise tolerance in bronchiectasis but there is no additional advantage of simultaneous IMT. IMT may, however, be important in the longevity of the training effects.

Breathing Exercises↗

PubMed1993

[Amiodarone in cardiac failure].

PURPOSE: To analyse the effects of amiodarone on the treatment of cardiac failure. METHODS: The effects of 200 mg/day of amiodarone were assessed in 18 patients with a history of cardiac failure. Functional class, heart rate, blood pressure, left ventricular ejection fraction, heart size, treadmill exercise tolerance and electrocardiogram were assessed before and eight weeks after the use of amiodarone, and the side effects were monitored. RESULTS: In 18 patients receiving amiodarone, the functional class and heart rate decreased significantly (p < 0.05) from 2.7 +/- 0.4 to 1.2 +/- 0.4 and 103 +/- 15 to 69 +/- 8.5 bpm respectively. The ejection fraction and the exercise tolerance increased significantly (p < 0.05) from 29.2 +/- 5.5% to 41.5% and from 379.8 +/- 271 sec to 897.8 +/- 350.8 sec, respectively. The incidence of atrial and ventricular arrhythmias decreased significantly and no side effects were observed. CONCLUSION: Amiodarone appears to produce benefits in patients with cardiac failure with atrial and ventricular arrhythmias.

Amiodarone↗

PubMed1999

Long-term effects of carvedilol in idiopathic dilated cardiomyopathy with persistent left ventricular dysfunction despite chronic metoprolol. The Heart-Muscle Disease Study Group.

OBJECTIVES: The purpose of this study was to analyze whether long-term treatment with the nonselective beta-adrenergic blocking agent carvedilol may have beneficial effects in patients with dilated cardiomyopathy (DCM), who are poor responders in terms of left ventricular (LV) function and exercise tolerance to chronic treatment with the selective beta-blocker metoprolol. BACKGROUND: Although metoprolol has been proven to be beneficial in the majority of patients with heart failure, a subset of the remaining patients shows long-term survival without satisfactory clinical improvement. METHODS: Thirty consecutive DCM patients with persistent LV dysfunction (ejection fraction < or =40%) and reduced exercise tolerance (peak oxygen consumption <25 ml/kg/min) despite chronic (>1 year) tailored treatment with metoprolol and angiotensin-converting enzyme inhibitors were enrolled in a 12-month, open-label, parallel trial and were randomized either to continue on metoprolol (n = 16, mean dosage 142+/-44 mg/day) or to cross over to maximum tolerated dosage of carvedilol (n = 14, mean dosage 74+/-23 mg/day). RESULTS: At 12 months, patients on carvedilol, compared with those continuing on metoprolol, showed a decrease in LV dimensions (end-diastolic volume -8+/-7 vs. +7+/-6 ml/m2, p = 0.053; end-systolic volume -7+/-5 vs. +6+/-4 ml/m2, p = 0.047), an improvement in LV ejection fraction (+7+/-3% vs. -1+/-2%, p = 0.045), a reduction in ventricular ectopic beats (-12+/-9 vs. +62+/-50 n/h, p = 0.05) and couplets (-0.5+/-0.4 vs. +1.5+/-0.6 n/h, p = 0.048), no significant benefit on symptoms and quality of life and a negative effect on peak oxygen consumption (-0.6+/-0.6 vs. +1.3+/-0.5 ml/kg/min, p = 0.03). CONCLUSIONS: In DCM patients who were poor responders to chronic metoprolol, carvedilol treatment was associated with favorable effects on LV systolic function and remodeling as well as on ventricular arrhythmias, whereas it had a negative effect on peak oxygen consumption.

Adrenergic beta-Antagonists↗

PubMed1995

Clinical comparison of acute single to dual chamber pacing in chronotropically incompetent patients with left ventricular dysfunction.

Dual chamber, rate responsive (DDDR) pacing is felt to be superior to ventricular, rate responsive (VVIR) pacing since it more closely mimics the normal electrical and hemodynamic activity of the heart. This reasoning has been used to justify the higher initial costs and increased complexity of dual chamber system. This study was designed to determine if objective criteria could be identified during acute testing justify implanting a dual chamber instead of a single chamber system in patients with left ventricular dysfunction. Eight patients with DDDR pacemakers (implanted for chronotropic incompetence) and left ventricular dysfunction underwent exercise radionuclide angiography and graded exercise treadmill testing. Each patient performed the tests in the single (VVIR) and dual (DDDR) chamber modes in a randomized, blinded fashion. We found that objective parameters such as ejection fraction (31% +/- 13% vs 31% +/- 10%), exercise tolerance (6.1 +/- 2.7 min vs 6.3 +/- 2.9 min), oxygen consumption (VO2) (941 +/- 286 mL/min vs 994 +/- 314 mL/min), carbon dioxide production (VCO2) (995 +/- 332 mL/min vs 1054 +/- 356 mL/min), and maximum attainable workload (43 +/- 24 W vs 46 +/- 22 W) did not differ between the single and dual chamber pacing modes. These findings suggest that in the acute setting, the additional cost and complexity of dual chamber, rate responsive pacing cannot be justified by objective improvements in exercise tolerance in patients with underlying left ventricular dysfunction.

Aged↗

PubMed1995

Can an echocardiographic score predict who will benefit clinically from balloon dilation of the mitral valve?

Deciding whether a patient with sub-optimal mitral valve anatomy will benefit from percutaneous mitral valvotomy remains a demanding clinical problem. We assessed the ability of an established echo score applied to transoesophageal images to predict absolute increases in mitral valve area and improvement in exercise capacity. Twenty five consecutive patients undergoing routine percutaneous mitral valvotomy were studied. Changes in exercise tolerance were measured by serial cardiorespiratory treadmill exercise testing. Before the procedure, exercise duration was directly related to mitral valve area (rs = 0.44, P < 0.05). Following percutaneous mitral valvotomy there was an increase in valve area (0.9 +/- 0.2 to 1.4 +/- 0.3 cm2, P < 0.0001) and repeat exercise testing demonstrated increases in exercise duration (470 +/- 220 to 610 +/- 240 s, P < 0.001) and peak VO2 (12.6 +/- 4.2 to 15.1 +/- 4.5 ml/kg/min, P < 0.01). There was an inverse correlation between the echo score and the increase in valve area (rs = -0.52, P < 0.05) but no relationship between the echo score and the increase in exercise duration or peak minute oxygen consumption (VO2). These data demonstrate that a score applied to transoesophageal images echocardiographic images can predict changes in mitral valve area but that the score fails to predict functional improvement for an individual patient. This suggests, therefore, that patients without contraindications to valvotomy whose valves have a high echo score should still be considered for valvotomy as they may benefit considerably from the procedure.

Adult↗

PubMed1995

Physical training in patients with stable chronic heart failure: effects on cardiorespiratory fitness and ultrastructural abnormalities of leg muscles.

OBJECTIVES: The present study was designed to evaluate the effect of an ambulatory training program on ultrastructural morphology and the oxidative capacity of skeletal muscle and its relation to central and peripheral hemodynamic variables in patients with chronic heart failure. BACKGROUND: Clinical evidence supports the hypothesis that exercise intolerance in patients with chronic heart failure is not only a consequence of low cardiac output, but is also a result of alterations in oxidative metabolism of skeletal muscle. METHODS: Twenty-two patients were prospectively randomized either to a training group (mean [+/-SD] ejection fraction 26 +/- 9%, n = 12) participating in an ambulatory training program or to a physically inactive control group (ejection fraction 27 +/- 10%, n = 10). At baseline and after 6 months, patients underwent symptom-limited bicycle exercise testing, and central and peripheral hemodynamic variables were measured. Percutaneous needle biopsy samples of the vastus lateralis muscle were obtained at baseline and after 6 months. The ultrastructure of skeletal muscle was analyzed by ultrastructural morphometry. RESULTS: After 6 months, patients in the training group achieved an increase in oxygen uptake at the ventilatory threshold of 23% (from 0.86 +/- 0.2 to 1.07 +/- 0.2 liters/min, p < 0.01 vs. control group) and at peak exercise of 31% (from 1.49 +/- 0.4 to 1.95 +/- 0.4 liters/min, p < 0.01 vs. control group). There was no significant change in oxygen uptake at the ventilatory threshold and at peak exercise in the control group. The total volume density of mitochondria and volume density of cytochrome c oxidase-positive mitochondria increased significantly by 19% (from 4.7 +/- 1.5 to 5.6 +/- 1.5 vol%, p < 0.05 vs. control group) and by 41% (from 2.2 +/- 1.0 to 3.1 +/- 1.0 vol%, p < 0.05 vs. control group) after 6 months of regular physical exercise. Cardiac output at rest and at submaximal exercise remained unchanged but increased during maximal symptom-limited exercise from 11.9 +/- 4.0 to 14.1 +/- 3.3 liters/min in the training group (p < 0.05 vs. baseline; p = NS vs. control group). Peak leg oxygen consumption increased significantly by 45% (from 510 +/- 172 to 740 +/- 254 ml/min, p < 0.01 vs. control group). Changes in cytochrome c oxidase-positive mitochondria were significantly related to changes in oxygen uptake at the ventilatory threshold (r = 0.82, p < 0.0001) and at peak exercise (r = 0.87, p < 0.0001). CONCLUSIONS: Regular physical training increases maximal exercise tolerance and delays anaerobic metabolism during submaximal exercise in patients with stable chronic heart failure. Improved functional capacity is closely linked to an exercise-induced increase in the oxidative capacity of skeletal muscle.

Biopsy↗

PubMed1996

Metabolic causes of equine exercise intolerance.

Metabolic causes of exercise intolerance can be subtle and difficult to document in horses. Because of increased metabolic rate in exercising muscle, most metabolic causes of exercise intolerance are clinically manifested by muscle abnormalities such as ER. Newer causes of ER are being documented by current research and are summarized in the article on muscular causes of equine exercise intolerance. Endocrine causes of exercise intolerance have been poorly documented, but recent work has shown the detrimental effects of hypothyroidism on exercise tolerance in horses. Many metabolic manifestations of exercise intolerance are cumulative in heat exhaustion; prevention by veterinary monitoring is the best treatment, followed by cold water bathing and oral or intravenous fluid and electrolyte replacement. Several ergogenic aids have been proposed and marketed for use in horses, but each has its own problems and few have been shown clearly to have positive effects on performance.

Acid-Base Equilibrium↗

PubMed1999

A controlled trial of exercise rehabilitation after heart transplantation.

BACKGROUND: In patients who have received a cardiac transplant, the denervated donor heart responds abnormally to exercise and exercise tolerance is reduced. The role of physical exercise in the treatment of patients who have undergone cardiac transplantation has not been determined. We assessed the effects of training on the capacity for exercise early after cardiac transplantation. METHODS: Twenty-seven patients who were discharged within two weeks after receiving a heart transplant were randomly assigned to participate in a six-month structured cardiac-rehabilitation program (exercise group, 14 patients) or to undergo unstructured therapy at home (control group, 13 patients). Each patient in the exercise group underwent an individualized program of muscular-strength and aerobic training under the guidance of a physical therapist, whereas control patients received no formal exercise training. Cardiopulmonary stress testing was performed at base line (within one month after heart transplantation) and six months later. RESULTS: As compared with the control group, the exercise group had significantly greater increases in peak oxygen consumption (mean increase, 4.4 ml per kilogram of body weight per minute [49 percent] vs. 1.9 ml per kilogram per minute [18 percent]; P=0.01) and workload (mean increase, 35 W [59 percent] vs. 12 W [18 percent]; P=0.01) and a greater reduction in the ventilatory equivalent for carbon dioxide (mean decrease, 13 [20 percent] vs. 6 [11 percent]; P=0.02). The mean dose of prednisone, the number of patients taking antihypertensive medications, the average number of episodes of rejection and of infection during the study period, and weight gain did not differ significantly between the groups. CONCLUSIONS: When initiated early after cardiac transplantation, exercise training increases the capacity for physical work.

Blood Pressure↗

PubMed1996

Permutation distribution estimation applied to the comparison of the profile of the activity of two antianginal drugs.

The comparison of the anti-ischemic activity of trimetazidine and propranolol was evaluated by multiple end points (clinical, exercise test, and ambulatory electrocardiogram [ECG] monitoring criteria) in 149 male patients with effort angina who received either trimetazidine 20 mg tid or propranolol 40 mg tid during a period of 3 months. The distribution of the standardized differences between the two treatments for each variable was obtained by a permutation method. The medians (estimation of the actual difference between the two treatments) and the 5, 25, 75 and 95% quantiles were represented on the same diagram for all end points. The pattern of the standardized distribution of the differences showed a similar activity of both drugs on symptoms and nitrates consumption, on exercise tolerance and increase in ischemic threshold at exercise, and on ischemia recorded at ambulatory ECG monitoring. Conversely, only propranolol decreased heart rate and rate pressure product at rest as well as at exercise, underlining the difference in the mode of action of the two drugs. This descriptive technique is an attractive method to evaluate the differences between drugs considering multiple criteria favouring the estimation of these differences together with their variability.

Angina Pectoris↗

PubMed2001

The cardiac response to exercise in cirrhosis.

BACKGROUND: Impaired exercise capacity and oxygen consumption are common in cirrhosis. AIM: To explore the relationship between possible myocardial dysfunction and exercise tolerance in cirrhosis. METHODS: Cardiac responses to exercise, using radionuclide angiography and graded upright cycle ergometry with oxygen consumption, were assessed before and after exercise in 39 cirrhotics patients and compared with 12 age and sex matched healthy volunteers. Baseline cardiac chamber dimensions and wall thickness, ejection fraction, and diastolic function were measured using two dimensional echocardiography is all subjects. RESULTS: Baseline diastolic dysfunction with prolonged isovolumic relaxation times (p=0.02), left atrial enlargement, and left ventricular wall thickening were present in all cirrhotics (p=0.02), despite increased mean ejection fraction. With graded exercise, cirrhotics achieved 71 (4)% (p=0.03) (pre-ascitics) and 46 (3)% (p<0.001) (ascitics) of predicted work loads, respectively, without significant increases in ejection fraction. The smaller absolute and percentage increases in cardiac output (p=0.003) in the cirrhotics were associated with significantly reduced oxygen consumption (p=0.003) and anaerobic threshold (p<0.001), and correlated significantly with work and metabolic parameters. CONCLUSIONS: Impaired exercise capacity in cirrhosis is associated with myocardial thickening and ventricular stiffness leading to decreased diastolic function, inotropic and chronotropic incompetence under conditions of stress, with metabolic consequences. This picture is compatible with the condition now known as cirrhotic cardiomyopathy.

Analysis of Variance↗

PubMed2005

Chronic heart failure, chronotropic incompetence, and the effects of beta blockade.

OBJECTIVE: To establish the prevalence of chronotropic incompetence in a cohort of patients with chronic heart failure (CHF) taking modern medications for heart failure, and whether this affected exercise capacity and predicted prognosis. METHODS: Heart rate response to exercise was examined in 237 patients with CHF in sinus rhythm, who were compared with 118 control volunteers. The percentage of maximum age predicted peak heart rate (%Max-PPHR) and percentage heart rate reserve (%HRR) were calculated, with a cut off of < 80% as the definition of chronotropic incompetence for both. Patients were followed up for an average (SD) of 2.8 (9) years. Mortality was related to peak oxygen consumption (pVo2), and the presence or absence of chronotropic incompetence. RESULTS: %Max-PPHR < 80% identified 103 (43%) and %HRR < 80% identified 170 patients (72%) as having chronotropic incompetence. Chronotropic incompetence was more common in patients taking beta blockers than in those not taking beta blockers as assessed by both methods (80 (49%) v 23 (32%) by %Max-PPHR and 123 (75%) v 47 (64%) by %HRR, respectively). Patients with chronotropic incompetence by either method had a lower pVo2 than those without. These differences remained significant for both patients taking and not taking a beta blocker. %HRR, Max-PPHR%, and HRR were related to New York Heart Association class and correlated with pVo2. There was no difference in the slopes relating heart rate to pVo2 between patients with and those without chronotropic incompetence (6.1 (1.7) v 5.1 (1.8), p = 0.34). During an average 2.8 year follow up 40 patients (17%) died. In Cox proportional hazard models, pVo2 was the most powerful predictor of survival and neither measure of chronotropic incompetence independently predicted outcome. CONCLUSIONS: pVo2 is a powerful marker of prognosis for patients with CHF whether they are taking beta blockers or not. A low heart rate response to exercise in patients with CHF correlates with worse exercise tolerance but is unlikely to contribute to exercise impairment.

Adrenergic beta-Antagonists↗

PubMed1998

A randomized comparison of exercise training in patients with normal vs reduced ventricular function.

BACKGROUND: Exercise training is recommended after myocardial infarction (MI) or bypass surgery in order to improve exercise tolerance. In some patients, the decrement in exercise capacity secondary to deconditioning and the left ventricular stunning associated with MI or coronary artery bypass graft (CABG) spontaneously improves after the event. However, the impact of the status of the left ventricle on these improvements is unknown. METHODS: Sixty-seven patients 1 month after MI or CABG were randomized to a training (n=34; age, 59+/-7 years) or a control group (n=33; age, 55+/-6 years). Forty-two patients had an ejection fraction >50% (22 in the training group and 20 in the control group), and 25 patients had an ejection fraction <40% (12 in the exercise group and 13 in the control group). After stabilization for approximately 1 month after the event, patients in the exercise group underwent 8 weeks of twice daily exercise at a residential rehabilitation center, while control patients received usual care. Initially and after 8 weeks, patients in both groups underwent maximal exercise testing with gas exchange and lactate analysis. RESULTS: Exercise training increased peak oxygen consumption (VO2) only in the reduced ejection fraction group (19.4+/-3.0 to 23.9+/-4.8 mL/kg/min; p<0.05); the exercise group with normal ventricular function did not change significantly. Changes in VO2 at the lactate threshold paralleled those of peak VO2 for both groups. Conversely, control patients with normal ventricular function increased peak VO2 spontaneously (20.8+/-3.9 to 24.8+/-3.5 mL/kg/min; p<0.01), whereas control patients with reduced ventricular function did not improve peak VO2. CONCLUSION: These data suggest that patients with depressed left ventricular function strongly benefit from rehabilitation, whereas most patients with preserved left ventricular function following MI or CABG tend to improve spontaneously 1 to 3 months after the event.

Coronary Artery Bypass↗