Peter J. Stafford

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After cardioversion from atrial fibrillation (AF) many patients develop early recurrence of the arrhythmia. While these patients may be appropriate for immediate prophylaxis against AF recurrence their identification at the time of cardioversion is not possible. Since the signal-averaged P wave (SAPW) is abnormal in individuals with atrial arrhythmia, we(More)
Examinations of both population genetic structure and the processes that lead to such structure in crocodilians have been initiated in several species in response to a call by the IUCN Crocodile Specialist Group. A recent study used microsatellite markers to characterize Morelet's crocodile (Crocodylus moreletii) populations in north-central Belize and(More)
AIMS The aim was to study regional fractionation and dominant frequency (DF) to determine if any relationship exists between the two parameters and also to assess the impact of limited left atrial ablation. METHODS AND RESULTS Patients undergoing catheter ablation of persistent AF using three-dimensional navigation were studied. Regional left atrial(More)
INTRODUCTION The role of substrates in the maintenance of persistent atrial fibrillation (persAF) remains poorly understood. The use of dominant frequency (DF) mapping to guide catheter ablation has been proposed as a potential strategy, but the characteristics of high DF sites have not been extensively studied. This study aimed to assess the DF(More)
OBJECTIVE To assess the reproducibility of time and frequency domain variables derived from the signal averaged P wave. DESIGN Longitudinal within patient study. SETTING Regional cardiothoracic centre. PATIENTS 20 patients (10 with documented paroxysmal atrial fibrillation and 10 normal controls) were studied on three occasions to assess the(More)
Frequency domain analysis of the signal-averaged P wave (SAPW) may provide additional information over time domain analysis in patients with paroxysmal atrial fibrillation (PAF), but an optimum method has not yet been defined. We compared two different approaches using SAPW and test signals. We analyzed the frequency spectrum of the entire P wave (method A)(More)
We have previously reported that the hypothalamo-pituitary-adrenal response to insulin-induced hypoglycaemia is normal while the cortisol release to pituitary stimulation by corticotrophin releasing factor (CRF-41) is reduced in obesity. Impaired growth hormone (GH) secretion is also found in obesity which may result from altered central levels of(More)
BACKGROUND Detailed analysis of signal-averaged P waves (SAPW) can provide insights into atrial electrophysiology. Abbreviated dosing of verapamil prior to cardioversion improves outcome at 1 week postcardioversion. The mechanism by which verapamil manifests benefit is uncertain. We hypothesized the SAPW would reflect any change in atrial electrophysiologic(More)
  • P J Stafford, D Robinson, R Vincent
  • British heart journal
  • 1995
OBJECTIVE To define the ability of analysis of the signal averaged P wave to identify patients with paroxysmal atrial fibrillation (AF) and establish whether differences in quantitative variables between patients and controls are due to concurrent cardiopulmonary disease, greater atrial dimension, or to unrelated changes in atrial electrophysiology. (More)
BACKGROUND The wide area circumferential ablation (WACA) approach to atrial fibrillation is thought to result in 'substrate modification' perhaps related to autonomic denervation. We examined this prospectively by comparing WACA and segmental pulmonary vein isolation (PVI) using noninvasive surrogate markers. METHODS Heart rate variability (HRV) and(More)