Mechanisms of exercise training in patients with heart failure

Background The reduction of exercise capacity because of fatigue and dyspnea in patients with heart failure can be improved with exercise training. We sought to examine the mechanisms of exercise training, as an adjunctive treatment strategy for patients with heart failure. Methods a reviewed the published data on the possible mechanisms of effect of exercise training in heart failure. Results Symptoms of heart failure may be explained on the basis of abnormal skeletal muscle perfusion and structure and endothelial function. Exercise training has been shown to engender changes in muscle structure and biochemistry and vascular function, although effects on cardiac function have not been detected uniformly and may require longer training periods. Conclusions A suitable, long-term program of exercise training may reverse unfavorable interactions among the heart, vessels, and skeletal muscles. These improvements may be preserved with an ongoing maintenance program.

Relationship of ventricular longitudinal function to contractile reserve in patients with mitral regurgitation

Background Latent left ventricular (LV) dysfunction in patients with valvular or myocardial disease may be identified by loss of contractile reserve (CR) at exercise echocardiography. Contraction in the LV longitudinal axis may be more sensitive than radial contraction to minor disturbances of LV function. We sought to determine whether tissue Doppler measurement of longitudinal function could be used to identify CR. Methods Exercise echocardiography was performed in 86 patients (20 women, age 53 +/- 18 years), 72 with asymptomatic or minimally symptomatic mitral regurgitation, and 14 normal controls. Pulsed-wave tissue Doppler imaging (DTI) was used to measure maximum annular systolic velocity at rest and stress. Inducible ischemia was excluded by analysis of wall motion by an experienced observer. CR was defined by greater than or equal to5% improvement of stress compared with rest ejection fraction (EF). Exercise capacity was assessed from expired gas analysis. Results CR was present in 34 patients with mitral regurgitation (47%); peak EF in patients with and without CR was 74% +/- 11% versus 54% +/- 15% (P

Usefulness of myocardial tissue Doppler echocardiography to evaluate left ventricular dyssynchrony before and after biventricular pacing in patients with idiopathic dilated cardiomyopathy

Tissue Doppler imaging allows assessment of left ventricular dyssynchrony and resynchronization after biventricular pacing.

Antibiotic desensitization in adults with cystic fibrosis

Objective: Allergic reactions to antibiotics occur in up to 30% of patients with cystic fibrosis (CF). Repeated antibiotic exposure and immune hyper-responsiveness increase the risk of allergic reactions and may limit antibiotic choice. Desensitization may allow the successful administration of an antibiotic despite previous allergy. We aimed to determine the success of antibiotic desensitization in patients with CF in an adult CF unit over a 7-year period. Methodology: A retrospective medical record review was performed on the 19 patients who had undergone antibiotic desensitization procedures. Data collected included drug allergy and intolerance profiles, nature of allergies, and the outcome of desensitization procedures. Desensitization procedures were performed in a ward setting according to published methods. Results: Nineteen patients (13 females) reported 62 drug allergies with a mean of 3.3 per patient. Of the 71 desensitization procedures undergone by this group, 54 (76%) were successful. Fifteen of the 19 patients were allergic to two or more beta-lactam antibiotics. Over half of the patients were desensitized to more than one antibiotic. Nine different antibiotics were used in 31 different patient/drug combinations. A successful outcome was achieved in 18/31 (58%) combinations, with three requiring treatment for mild allergic reactions. Allergic reactions caused drug cessation in a total of 19 patient/drug combinations (three after initial successful desensitization and full courses of antibiotics). Over 50% of these reactions occurred on day 1. Desensitization failures were more common in patients with well-documented allergic reactions to a specific drug. Conclusion: This study demonstrates that multiple antibiotic allergies are common in adults with CE Cross-reactivity between beta-lactam antibiotics may limit antibiotic choice for the treatment of pulmonary exacerbations. Antibiotic desensitization allows safe and successful treatment in the ward setting of many patients with previous allergies to an antibiotic. In many patients symptoms of allergy still occur and result in cessation of the antibiotics. Use of corticosteroids and antihistamines may improve the success rate of desensitization procedures.

The basal ganglia and semantic engagement: Potential insights from semantic priming in individuals with subcortical vascular lesions, Parkinson's disease, and cortical lesions

The impact of basal ganglia dysfunction on semantic processing was investigated by comparing the performance of individuals with nonthalamic subcortical (NS) vascular lesions, Parkinson's disease (PD), cortical lesions, and matched controls on a semantic priming task. Unequibiased lexical ambiguity primes were used in auditory prime-target pairs comprising 4 critical conditions; dominant related (e.g., bank-money), subordinate related (e.g., bank-river), dominant unrelated (e.g.,foot-money) and subordinate unrelated (e.g., bat-river). Participants made speeded lexical decisions (word/nonword) on targets using a go-no-go response. When a short prime-target interstimulus interval (ISI) of 200 ins was employed, all groups demonstrated priming for dominant and subordinate conditions, indicating nonselective meaning facilitation and intact automatic lexical processing. Differences emerged at the long ISI (1250 ms), where control and cortical lesion participants evidenced selective facilitation of the dominant meaning, whereas NS and PD groups demonstrated a protracted period of nonselective meaning facilitation. This finding suggests a circumscribed deficit in the selective attentional engagement of the semantic network on the basis of meaning frequency, possibly implicating a disturbance of frontal-subcortical systems influencing inhibitory semantic mechanisms.