Biomedical subjects

Thomas Crawford

Publications and source records attributed to Thomas Crawford.

6 recordsLinked to original sources

PubMed2006

Risk of thromboembolic events after percutaneous left atrial radiofrequency ablation of atrial fibrillation.

BACKGROUND: In patients with atrial fibrillation (AF), the risk of thromboembolic events (TEs) is variable and is influenced by the presence and number of comorbid conditions. The effect of percutaneous left atrial radiofrequency ablation (LARFA) of AF on the risk of TEs is unclear. METHODS AND RESULTS: LARFA was performed in 755 consecutive patients with paroxysmal (n = 490) or chronic (n = 265) AF. Four hundred eleven patients (56%) had > or = 1 risk factor for stroke. All patients were anticoagulated with warfarin for > or = 3 months after LARFA. A TE occurred in 7 patients (0.9%) within 2 weeks of LARFA. A late TE occurred 6 to 10 months after ablation in 2 patients (0.2%), 1 of whom still had AF, despite therapeutic anticoagulation in both. Among 522 patients who remained in sinus rhythm after LARFA, warfarin was discontinued in 79% of 256 patients without risk factors and in 68% of 266 patients with > or = 1 risk factor. Patients older than 65 years or with a history of stroke were more likely to remain anticoagulated despite a successful outcome from LARFA. None of the patients in whom anticoagulation was discontinued had a TE during 25 +/- 8 months of follow-up. CONCLUSIONS: The risk of a TE after LARFA is 1.1%, with most events occurring within 2 weeks after the procedure. Discontinuation of anticoagulant therapy appears to be safe after successful LARFA, both in patients without risk factors for stroke and in patients with risk factors other than age > 65 years and history of stroke. Sufficient safety data are as yet unavailable to support discontinuation of anticoagulation in patients older than 65 years or with a history of stroke.

Aged↗

PubMed2006

A tailored approach to catheter ablation of paroxysmal atrial fibrillation.

BACKGROUND: Because the genesis of atrial fibrillation (AF) is multifactorial and variable, an ablation strategy that involves pulmonary vein isolation and/or a particular set of ablation lines may not be equally effective or efficient in all patients with AF. A tailored strategy that targets initiators and drivers of AF is a possible alternative to a standardized lesion set. METHODS AND RESULTS: Catheter ablation was performed in 153 consecutive patients (mean age, 56+/-11 years) with symptomatic paroxysmal AF with the use of an 8-mm tip radiofrequency ablation catheter. The esophagus was visualized with barium. The pulmonary veins and left atrium were mapped during spontaneous or induced AF. Arrhythmogenic pulmonary veins were isolated or encircled. If AF was still present or inducible, complex electrograms in the left atrium, coronary sinus, and superior vena cava were targeted for ablation. The end point of ablation was absence of frequent atrial ectopy and spontaneous AF during isoproterenol infusion and noninducibility of AF. Routine energy applications near the esophagus were avoided. During follow-up, left atrial flutter developed in 19% of patients and was still present in 10% at >12 weeks of follow-up. A repeat ablation procedure was performed in 18% of patients. During a mean follow-up of 11+/-4 months, 77% of patients were free from AF and/or atrial flutter without antiarrhythmic drug therapy. Pericardial tamponade or transient neurological events occurred in 2% of procedures. CONCLUSIONS: A tailored ablation strategy that only targets triggers and drivers of AF is feasible and eliminates paroxysmal AF in approximately 80% of patients.

Aged↗

PubMed2006

Social role and birth cohort influences on gender-linked personality traits in women: a 20-year longitudinal analysis.

Growth curve modeling was used to examine the impact of social role experiences (e.g., marital support, occupational prestige) and birth cohort on mean-level differences and age-related changes in positive personality traits indicative of either femininity or masculinity in 758 mothers heterogeneous in age, assessed 4 times over 2 decades. Both femininity and masculinity increased significantly from mean ages 39 through 59; each was predictive of an age change in the other. Low masculinity was associated with a more rapid increase in femininity, whereas high occupational prestige decreased the magnitude of association between masculinity and femininity. Femininity increased with more marital support but decreased with unmarried status, more children at home, and working full or part time; among full-time workers, that effect was modified by marital support. Masculinity increased with full-time work and high occupational prestige. A trend for differing levels of femininity, and contrasting associations of masculinity with femininity and marital conflict in women born after 1944 compared with those born earlier, suggests shifting social norms and gender relations in the marital role.

Adult↗

PubMed2005

Peripheral pathways regulate motoneuron collateral dynamics.

Motor axons regenerating after repair of mixed nerve reinnervate pathways leading to muscle more often than those leading to skin [preferential motor reinnervation (PMR)]. Motoneurons that initially project collaterals to both muscle and skin prune incorrect projections to generate specificity. The number of motor axon collaterals maintained entirely within cutaneous or muscle pathways, however, is unknown. To overcome this shortcoming, dorsal root ganglion excision has been used to allow only motor axons to regenerate after a peripheral lesion. Motor axon number in reinnervated cutaneous and muscle pathways can then be correlated with the number of parent motoneurons determined by retrograde labeling. The number of collaterals per neuron can be calculated for each environment and the relative roles of pathway and end organ assessed by blocking the distal pathways to prevent target reinnervation. Without sensory competition, PMR develops in two stages: a limited response to muscle nerve and then a robust response to muscle that may involve retrograde signaling to the proximal pathway. Motoneurons maintain more collaterals in cutaneous nerve than in muscle nerve, even without muscle contact. This difference could result either from increased collateral formation in cutaneous nerve or from increased collateral pruning in muscle nerve. In either instance, these findings confirm that muscle and cutaneous pathways have functionally significant identities that can be recognized by motor axons and can regulate their arborization. Decreased arborization in muscle pathways could promote regeneration by focusing neuronal resources on high-yield projections; increased arborization in cutaneous pathways, conversely, would enhance pathfinding abilities.

Animals↗

PubMed2005

Adolescent Cluster A personality disorder symptoms, role assumption in the transition to adulthood, and resolution or persistence of symptoms.

Cluster A odd or eccentric personality disorder (PD) symptoms may reflect a schizophrenia spectrum biological vulnerability in at least some persons. Consequently, this symptom pattern may have particularly negative effects on the transition from adolescent to adult roles. A general population sample of 200 young adults was assessed on Cluster A PD at mean ages 17 and 22, and subsequently provided detailed narratives about their monthly experiences and behaviors between these two ages. Adolescent Cluster A PD was related to the developmental trajectories of residential, career, financial, romantic, and family formation roles during this period, and trajectories were related to a change in symptoms over this period. Symptoms were associated with early parenthood and less advanced education, but for other developmental outcomes tended to differ for men and women. These gender differences were attributable, in part, to the differential meaning and consequences of early parenthood for men and women.

Adolescent↗

PubMed2002

Cerebellar ataxia as the presenting manifestation of Lyme disease.

A 7-year-old boy from suburban Baltimore who presented with cerebellar ataxia and headaches was found by magnetic resonance imaging to have multiple cerebellar enhancing lesions. He had no history of tick exposure. He was initially treated with steroids for presumptive postinfectious encephalitis. Lyme disease was diagnosed 10 weeks later after arthritis developed. Testing of the cerebrospinal fluid obtained at the time cerebellar ataxia was diagnosed revealed intrathecal antibody production to Borrelia burgdorferi. Treatment with intravenous antibiotics led to rapid resolution of persistent cerebellar findings.

Anti-Bacterial Agents↗