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Biomedical subjects

Peter A Brady

Publications and source records attributed to Peter A Brady.

6 recordsLinked to original sources
PubMed2005

Inappropriate sinus tachycardia, postural orthostatic tachycardia syndrome, and overlapping syndromes.

BACKGROUND: Inappropriate sinus tachycardia (IAST) and postural orthostatic tachycardia syndrome (POTS) are syndrome complexes with some distinctive features, overlapping clinical manifestations, and potential common mechanisms. Pathogenesis of these overlapping syndromes is poorly understood. Diagnostic and therapeutic approaches have not been standardized. PURPOSE: This article provides an overview of the definition, clinical presentation, and proposed mechanisms of IAST and other overlapping syndromes. A stepwise diagnostic approach is suggested. A multidisciplinary management scheme is outlined. METHODS: A MEDLINE search for English-language articles on IAST, POTS, and chronic orthostatic intolerance published up to 2005 was performed. Published data incorporated with our clinical experience were synthesized and presented in this review. RESULTS: The population of IAST is heterogeneous and underlying mechanisms are complex and likely multifactorial. Evidence suggests that both cardiac and extracardiac causes are plausible. Regional and limited autonomic neuropathies, at least in part, can provide a mechanism-based explanation of the cardiovascular indices and clinical symptoms in a significant number of patients with IAST. The regional abnormalities can be detected by autonomic testing. Among patients with IAST and evidence of autonomic dysregulation, an integrated autonomic, cardiovascular, and psychiatric management approach appears to be logical and rational when appropriate. Sinus node ablation could be considered in patients with persistent IAST in the absence of autonomic neuropathy and multisystem symptoms. Data from long-term outcomes are lacking. CONCLUSION: The current understanding of IAST mechanisms is incomplete and management approach is not adequate. Significant effort needed in clinical research to improve therapeutic outcome.

Humans↗
PubMed2004

Syncope Evaluation in the Emergency Department Study (SEEDS): a multidisciplinary approach to syncope management.

BACKGROUND: The primary aim and central hypothesis of the study are that a designated syncope unit in the emergency department improves diagnostic yield and reduces hospital admission for patients with syncope who are at intermediate risk for an adverse cardiovascular outcome. METHODS AND RESULTS: In this prospective, randomized, single-center study, patients were randomly allocated to 2 treatment arms: syncope unit evaluation and standard care. The 2 groups were compared with chi2 test for independence of categorical variables. Wilcoxon rank sum test was used for continuous variables. Survival was estimated with the Kaplan-Meier method. One hundred three consecutive patients (53 women; mean age 64+/-17 years) entered the study. Fifty-one patients were randomized to the syncope unit. For the syncope unit and standard care patients, the presumptive diagnosis was established in 34 (67%) and 5 (10%) patients (P<0.001), respectively, hospital admission was required for 22 (43%) and 51 (98%) patients (P<0.001), and total patient-hospital days were reduced from 140 to 64. Actuarial survival was 97% and 90% (P=0.30), and survival free from recurrent syncope was 88% and 89% (P=0.72) at 2 years for the syncope unit and standard care groups, respectively. CONCLUSIONS: The novel syncope unit designed for this study significantly improved diagnostic yield in the emergency department and reduced hospital admission and total length of hospital stay without affecting recurrent syncope and all-cause mortality among intermediate-risk patients. Observations from the present study provide benchmark data for improving patient care and effectively utilizing healthcare resources.

Aged↗
PubMed2002

Slowed conduction and ventricular tachycardia after targeted disruption of the cardiac sodium channel gene Scn5a.

Voltage-gated sodium channels drive the initial depolarization phase of the cardiac action potential and therefore critically determine conduction of excitation through the heart. In patients, deletions or loss-of-function mutations of the cardiac sodium channel gene, SCN5A, have been associated with a wide range of arrhythmias including bradycardia (heart rate slowing), atrioventricular conduction delay, and ventricular fibrillation. The pathophysiological basis of these clinical conditions is unresolved. Here we show that disruption of the mouse cardiac sodium channel gene, Scn5a, causes intrauterine lethality in homozygotes with severe defects in ventricular morphogenesis whereas heterozygotes show normal survival. Whole-cell patch clamp analyses of isolated ventricular myocytes from adult Scn5a(+/-) mice demonstrate a approximately 50% reduction in sodium conductance. Scn5a(+/-) hearts have several defects including impaired atrioventricular conduction, delayed intramyocardial conduction, increased ventricular refractoriness, and ventricular tachycardia with characteristics of reentrant excitation. These findings reconcile reduced activity of the cardiac sodium channel leading to slowed conduction with several apparently diverse clinical phenotypes, providing a model for the detailed analysis of the pathophysiology of arrhythmias.

Animals↗
PubMed2002

When is intracardiac electrophysiologic evaluation indicated in the older or very elderly patient? Complications rates and data.

The use of invasive EPS and catheter ablation is well established for many cardiac rhythm disorders. Because of the high prevalence of arrhythmias, which often are tolerated poorly in the elderly, and the increased frequency of adverse effects of pharmacologic therapy in this population, the potential for benefit from invasive EPS and catheter ablation is great. The notion that elderly patients are at increased risk of complications from invasive EPS is not borne out by available data. Therefore, the suitability of this form of diagnostic and therapeutic approach should be based on the assessment of the individual patient and the clinical context, while taking into consideration patient-specific risks, goals, and expectations in adopting an invasive strategy.

Aged↗