Thomas A. Dewland

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Heart rate variability and postexercise heart rate recovery are used to assess cardiac parasympathetic tone in human studies, but in some cases these indexes appear to yield discordant information. We utilized pyridostigmine, an acetylcholinesterase inhibitor that selectively augments the parasympathetic efferent signal, to further characterize(More)
BACKGROUND Because the association between atrial fibrillation (AF) and race has only been rigorously compared in population-based studies that dichotomized participants as white or black, it is unclear whether white race confers elevated AF risk or black race affords AF protection. METHODS AND RESULTS The Healthcare Cost and Utilization Project was used(More)
IMPORTANCE Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain. OBJECTIVE To compare outcomes of single-(More)
Atrial flutter ablation is associated with a high rate of acute procedural success and symptom improvement. The relationship between ablation and other clinical outcomes has been limited to small studies primarily conducted at academic centers. We sought to determine if catheter ablation of atrial flutter is associated with reductions in healthcare(More)
BACKGROUND Premature cardiac contractions are associated with increased morbidity and mortality. Though experts associate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) with caffeine, there are no data to support this relationship in the general population. As certain caffeinated products may have cardiovascular benefits,(More)
BACKGROUND Advanced age is the most important risk factor for atrial fibrillation (AF); however, the mechanism remains unknown. Telomeres, regions of DNA that shorten with cell division, are considered reliable markers of biological aging. We sought to examine the association between leukocyte telomere length (LTL) and incident AF in a large(More)
BACKGROUND Transseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative(More)
OBJECTIVE  To investigate the relation between alcohol consumption and heart disease by using differences in county level alcohol sales laws as a natural experiment. DESIGN  Observational cohort study using differences in alcohol sales laws. SETTING  Hospital based healthcare encounters in Texas, USA. POPULATION  1 106 968 patients aged 21 or older(More)
Whites have an increased risk of atrial fibrillation (AF) compared to Blacks. The mechanism underlying this association is unknown. Left atrial (LA) size is an important AF risk factor, and studies in older adults suggest Whites have larger LA diameters. However, because AF itself causes LA dilation, LA size differences may be due to greater subclinical AF(More)
an an a d d d Bi Bi Bios o osta ta tati ti ist st stic ic ics, s s, U U Uni ni nive ve v rs rs rsit it ity y y of o C Ca alif for or orni ni nia, a a, S San an an F F Fra ra ranc nc ncis is isco c , , CA CA CA f Address for r r Co Co Corr rr rres es espo po pond nd n en en enc c ce: : Abstract Background—As the association between atrial fibrillation (AF)(More)
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