Introduction: We previously have shown that a 3-minute single-stage adenosine tilt test has a diagnostic yield comparable to a two-stage protocol consisting of a 30-minute drug-free tilt followed by a 15-minute isoproterenol tilt. In this study, we sought to further define the clinical utility of adenosine tilt testing in patients with unexplained syncope by prospectively evaluating test specificity and determining predictors of a positive test response.
Methods And Results: The specificity of single-stage adenosine tilt testing was determined using 30 control subjects. To determine the diagnostic yield of this protocol, adenosine tilts were performed in 129 patients with unexplained syncope. The adenosine tilt test protocol had high specificity (100%) but a low overall diagnostic yield (18%). However, the yield was affected significantly by age. In patients =40 years of age, the tilt test was positive in 15 (41%) of 37 patients, which was significantly greater than the yield in patients between the ages of 41 and 64 years (6/41 patients [15%], P = 0.012) and those >/=65 years of age (2/41 patients [5%], P < 0.0001).
Conclusion: These data support single-stage adenosine tilt testing in patients =40 years of age because the diagnostic yield of the test is maximal in this group and the test can be completed in =3 minutes. Conversely, the diagnostic yield of adenosine tilt testing in patients >40 years of age is low, suggesting that the clinical utility of this protocol is limited in these patients.
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http://dx.doi.org/10.1046/j.1540-8167.2004.03556.x | DOI Listing |
Molecules
November 2023
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
The integration of phosphorus chemistry with the mechanism of ATP synthesis/hydrolysis requires dynamical information during ATP turnover and catalysis. Oxygen exchange reactions occurring at β-catalytic sites of the FF-ATP synthase/F-ATPase imprint a unique record of molecular events during the catalytic cycle of ATP synthesis/hydrolysis. They have been shown to provide valuable time-resolved information on enzyme catalysis during ATP synthesis and ATP hydrolysis.
View Article and Find Full Text PDFInt J Mol Sci
October 2023
AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.
The CCT/TRiC complex is a type II chaperonin that undergoes ATP-driven conformational changes during its functional cycle. Structural studies have provided valuable insights into the mechanism of this process, but real-time dynamics analyses of mammalian type II chaperonins are still scarce. We used diffracted X-ray tracking (DXT) to investigate the intramolecular dynamics of the CCT complex.
View Article and Find Full Text PDFEur J Intern Med
November 2022
Medirex Laboratory, Košice, Slovakia.
Introduction: Adenosine is mediator regulating physiological and pathological processes in organism. It probably plays a role in pathogenesis of vasovagal syncopes (VVS), too. Adenosine, its receptors and degradation enzymes- adenosinedeaminase (ADA) and adenosinekinase (ADK), are called the adenosinergic system.
View Article and Find Full Text PDFInt Emerg Nurs
September 2022
Master of Nursing, John Hunter Emergency Department, Australia. Electronic address:
A 36 year old woman with chest pain and palpitations at 34 weeks gestation (gravidity 2, parity 1) presented to the emergency department where she was found to be in supraventricular tachycardia (SVT). This patient had an earlier episode of SVT during the same pregnancy that was managed with intravenous adenosine. During both presentations a REVERT trial style 'modified' Valsalva manoeuvre (including supine positioning with passive leg raise) was attempted without success.
View Article and Find Full Text PDFInt J Cardiol
October 2022
Emeritus Professor of Clinical Cardiology, Department of Cardiology, Hammersmith Hospital, National Heart & Lung Institute, Imperial College, London W12 0HS, United Kingdom. Electronic address:
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