Surgery & Anaesthesia :: Research

Physiological Rhythms Unit    

 

 

 

 

Research Interests

We are interested in exploring cardiovascular and respiratory interactions using a range of time series analysis tool.

Current areas of interest include:

  • Heart Rate Variability – periodic variations in heart rate and blood pressure. We are interested in the physiological significance of heart rate and blood pressure variability, and the time series analysis of heart rate variability under different conditions.

  • Cardioventilatory coupling – the entrainment of inspiratory onset by a cardiovascular afferent input. We are interested in the mechanism of entrainment, and the physiological consequences of entrainment of inspiratory timing to a non-respiratory afferent input.

  • Ventricular Fibrillation – we are interested in the time series analysis of this lethal arrhythmia, and the information content of signals derived from implanted cardioverter defibrillator patients and in models of acute ischaemia.

  • Breath to breath respiratory variability – We are interested in the control of respiratory timing, particularly during sleep and in the newborn and infant, the occurrence of central apnoeas, and patterns of breathing during anaesthesia.

  • Blood pressure control: the role of breathing on the regulation of baroreflex sensitivity.

  • Integration of peripheral blood pressure and cerebral blood flow control

Current funding

National Heart Foundation
Wellington Medical Research Foundation
J Campbell Barrett Wellington Anaesthesia Trust
Lotteries Health Research
Greenlane Cardiovascular Research Trust
Health Research Council

 

Current Lab Personnel

Associate Professor Duncan Galletly
Dr Peter Larsen
Dr. Shieak Tzeng
Dr Dawn Elder (PhD student)
Ms Karyn O’Keeffe (PhD student)
Mrs Helen Horsman (PhD student)
Mr Peter Sin (PhD student)
Mrs Ellen Woodcock (Ass. Lect. & PhD student)
Mr Praveen de Silva (BMedSci)

Collaborators

Dr Nigel Lever, Cardiologist, University of Auckland
Assoc. Prof. Phil Ainslie (Physiology, University of British Columbia, Okanagan)
Dr Sam Lucas (Physiology, Dunedin School of Medical Sciences)
Dr Stephen Brown (Exercise Physiology, Massey University)
Dr Matt Webber (Cardiology Registrar, Wellington Hospital)
Dr Alexander Sasse (Consultant Cardiologist, Wellington Hospital)
Dr Iain Melton (Cardiologist, Christchurch Hospital)
Dr Scott Harding (Cardiologist, Wellington Hospital)

Recent Publications

JOURNAL OF THE AMERICAN HEART ASSOCIATION
Article Type: Letters to the Editor
STROKE/2009/570853 VERSION 1
Yu Chieh Tzeng, Chris K Willie, and Philip N Ainslie
BAROREFLEX, CEREBRAL PERFUSION AND STROKE: INTEGRATIVE PHYSIOLOGY AT ITS Best

SJE Lucas, YC Tzeng, SD Galvin,, KN Thomas, S Ogoh, PN Ainslie. Influence of changes in blood pressure on cerebral perfusion and oxygenation. Hypertension 2009 (in press).

S Ogoh, SJE Lucas, YC Tzeng, SD Galvin, PN Ainslie. Influence of heart rate on dynamic cerebral blood flow regulation during acute hypotension: consideration of the arterial baroreflex. J Physiol 2009 (in press).

PYW Sin, YC Tzeng, DC Galletly. Cardioventilatory coupling and pulmonary gas exchange efficiency in humans. Autonomic Neuroscience. 2009; 149:75.

YC Tzeng, PYW Sin, SJE Lucas & PN Ainslie. Respiratory modulation of baroreflex sensitivity. Journal of Applied Physiology 2009 (in- press).

Nigel A Lever, Peter D Larsen, Mathew Dawes, Annie Wong, Scott A Harding. Are our medical graduates in New Zealand safe and accurate in ECG interpretation? New Zealand Medical Journal, 3 April 2009, Vol 122 No 1292; ISSN 1175 8716.

Comments on Point: Counterpoint: Respiratory sinus arrhythmia is due to a central mechanism vs. respiratory sinus arrhythmia is due to the baroreflex mechanism Claude Julien, Michael J. Parkes, Shieak Y. C. Tzeng, Peter Y. W. Sin, Philip N. Ainslie, Philippe van de Borne, Jacques-Olivier Fortrat, Marc-Antoine Custaud, Claude Gharib, Alberto Porta, Frederic Vallais, Giuseppe Baselli, Massimo Pagani, Daniela Lucini, Richard L. Hughson, J. Andrew Taylor, Can Ozan Tan, David M. Baekey, Thomas E. Dick, Julian F. R. Paton, and Basel Taha
J Appl Physiol 2009;106 1745-1749

YC Tzeng, PYW Sin, DC Galletly. Human sinus arrhythmia: Inconsistencies of a teleological hypothesis. American Journal of Physiology, Heart and Circulatory Physiology. 2009: 296: H65-H7O.

Elder DE, Larsen PD, Zuccollo JM. Failure of apnoea monitoring during bed-sharing. Forensic Science, Medicine and Pathology 2008;4:167-169.

Lever NA, Newell GG, Larsen PD. Differences in the characteristics of induced and spontaneous episodes of ventricular fibrillation. Europace 9:1054, 2007.

Melinda M. Parnell, Peter D Larsen. Poor quality teaching in lay person CPR courses. Resuscitation 2007.

Psychological implications of ICD implantation in a New Zealand population. E G Newall, N A Lever, S Prasad, C Hornabrook, P D Larsen. Europace 2007

Effects of hypercapnia and hypoxemia on respiratory sinus arrhythmia in conscious humans during spontaneous respiration. Tzeng YC, Larsen PD, Galletly DC. American Journal of Physiology, Heart and Circulatory Physiology 2007; 292: H2397-H2407.

Mechanism of cardioventilatory coupling: insights from cardic pacing, vagotomy, and sino-aortic denervation in the anaesthetized rat.  Tzeng YC, Larsen PD, Galletly DC. American Journal of Physiology, Heart and Circulatory Physiology 2007; 292: H1967-H1977.

 

We welcome applicants interested in doing research towards summer studentships, BMedSci, MMedSci. or PhD in the areas mentioned above.  For enquires please contact Christa Hesse (Research Coordinator): christa.hesse@otago.ac.nz

 

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