Understanding The Mechanisms Of Atrial Fibrillation: High Density Intra-operative Mapping
Funder
National Health and Medical Research Council
Funding Amount
$94,025.00
Summary
We hypothesize that: During atrial fibrillation, regions acting as short cycle length drivers will demonstrate characteristic sinus rhythm electrophysiology including conduction slowing and abbreviated refractoriness. We aim to correlate the nature of electrical activity in atrial fibrillation with that in sinus rhythm. We will focus on particular anatomic locations that have been shown to be regions of anisotropy and sites where short cycle length rotors have been observed. The anatomic locat ....We hypothesize that: During atrial fibrillation, regions acting as short cycle length drivers will demonstrate characteristic sinus rhythm electrophysiology including conduction slowing and abbreviated refractoriness. We aim to correlate the nature of electrical activity in atrial fibrillation with that in sinus rhythm. We will focus on particular anatomic locations that have been shown to be regions of anisotropy and sites where short cycle length rotors have been observed. The anatomic location and electrophysiologic (EP) characteristics of these regions will vary according to the underlying atrial substrate. We aim to characterise the differences in atrial electrophysiology in AF and sinus rhythm between different pathophysiologic substrates. With high density mapping targeted to critical anatomic sites it will be possible to determine the EP mechanism of short cycle length rotors. We aim to characterise the EP mechanism of these short cycle length regions by analysis of recordings from high density mapping plaques.Read moreRead less
Utility Of Direct Endocardial Visualisation To Characterise Scar Morphology And Ablation Lesion Formation
Funder
National Health and Medical Research Council
Funding Amount
$421,285.00
Summary
Endocardial visualisation is a new technique in which a catheter is used to look at the internal surface of the heart without the need for surgery. We will use the visualisation catheter to find a better way of placing small burns within the heart to stop atrial fibrillation (one of the most common heart diseases). We will also use the visualisation catheter to find a better way of locating the scarred areas of the heart responsible for ventricular tachycardia (another common heart disease).
INFORM-AF A Randomised Controlled Trial To Assess The Efficacy Of A Digital Education Program For Atrial Fibrillation
Funder
National Health and Medical Research Council
Funding Amount
$606,009.00
Summary
This grant aims to evaluate a new digital education program to improve quality of life for people living with atrial fibrillation and reduce rehospiatlisations.
Improving Outcomes In Patients With Life-threatening Ventricular Arrhythmias
Funder
National Health and Medical Research Council
Funding Amount
$606,009.00
Summary
This grant focuses on improving outcomes in patients with life-threatening ventricular arrhythmias (VAs). The AUGMENT-VA trial compares standard techniques for energy delivery during cardiac arrest with ‘manual pressure augmentation’, a novel technique which may improve energy delivery to the heart & restore normal rhythm sooner. The SUBSTRATE-VA study looks at the role of invasive mapping of the heart for unexplained VAs to identify subtle abnormalities that could be targeted for treatment.
The Role Of Mechanoelectric Feedback In Cardiac Arrhythmogenesis
Funder
National Health and Medical Research Council
Funding Amount
$307,550.00
Summary
Arrhythmias are disruptions of the normal electrical rhythm of the heart, and can vary from asymptomatic to fatal. It used to be thought that the electrical and mechanical functions of the heart muscle were essentially separate: the electrical activity triggered contraction something like pulling the trigger of a gun- once events were in motion, the electrical events played no further role. However, in recent years it has become apparent that this is an over-simplification of the real situation. ....Arrhythmias are disruptions of the normal electrical rhythm of the heart, and can vary from asymptomatic to fatal. It used to be thought that the electrical and mechanical functions of the heart muscle were essentially separate: the electrical activity triggered contraction something like pulling the trigger of a gun- once events were in motion, the electrical events played no further role. However, in recent years it has become apparent that this is an over-simplification of the real situation. In fact, the electrical activity of the heart is influenced strongly by the degree and timing of stretch to which the heart muscle is subjected, a process called Mechano-electric feedback. Since it can be demonstrated in isolated tissues, mechano-electric feedback must be an intrinsic property of the heart muscle. It has been shown in isolated heart preparations that passive stretch produces electrical disturbances in the normal action potential shape and propagation and that these electrical disturbances can be powerful enough to generate severe arrhythmias. There are paralells in human diseases. For example, atrial arrhythmias are common in older people, and it seems that these may be due to chronic stretch of the atria, as a consequence of high blood pressure. In addition, in those patients recovering from a heart attack, it seems likely that the damaged part of the heart muscle subjects the surrounding tissue to unusual mechanical stresses, and may trigger arrhythmias. This project aims to investigate the mechanisms underlying this mechano-electric feedback, in an attempt to understand some types of arrhythmias. Using molecular biology techniques, we will look at the gene expression of a novel type of stretch-activated potassium channel in both healthy and diseased animal hearts, with the aim of seeing if changes in the level of expression of these channels is correlated with changes in the response of the heart to stretch.Read moreRead less