Efficacy And Mechanisms Of Exercise Training In Diastolic Heart Failure
Funder
National Health and Medical Research Council
Funding Amount
$385,250.00
Summary
Heart failure is modern epidemic which presents a significant public health burden, due to a high mortality, frequent hospital admissions and impaired functional capacity. Although the typical heart failure patient presents with a reduced contractile function, many patients have typical heart failure symptoms but with normal contraction. The problem in these patients seems to relate to the heart's ability to fill with blood, and this entity is known as diastolic heart failure (DHF). This syndrom ....Heart failure is modern epidemic which presents a significant public health burden, due to a high mortality, frequent hospital admissions and impaired functional capacity. Although the typical heart failure patient presents with a reduced contractile function, many patients have typical heart failure symptoms but with normal contraction. The problem in these patients seems to relate to the heart's ability to fill with blood, and this entity is known as diastolic heart failure (DHF). This syndrome is most frequently due to ischemic or hypertensive heart disease, and most commonly occurs in the elderly. The optimal management of DHF is not well defined, although some drug trials are currently in progress. A number of studies have shown exercise training to improve functional capacity by 15-20% in typical heart failure. However, training has not so far been trialled in DHF. In this multicenter, multi-disciplinary study, we will study a training and control group to determine whether exercise capacity and DHF symptoms are responsive to exercise training. This work will teach us about the optimum exercise prescription, in terms of the duration and nature of training, as well as the safety and effectiveness of exercise training. By using a number of sensitive measurements of heart and vessel function (in which our group has special expertise), we will identify whether exercise training exerts its effect through improvement in vascular function and myocardial properties. If successful, the clinical implications of this study are that; 1. Exercise training will be adopted to improve functional capacity and symptoms of DHF 2. The merits of aerobic and strength training will be identified in DHF 3. Abnormal blood vessel function will be identified as a major and reversible contributor to DHFRead moreRead less
Importance Of The Transmural Distribution Of Viable Myocardium To Outcome Of Patients After Revascularization
Funder
National Health and Medical Research Council
Funding Amount
$268,800.00
Summary
After a heart attack, up to 50% of tissue showing reduced function can recover if blood supply is returned to normal with bypass surgery or balloon angioplasty. Because these procedures may be risky in cardiac patients, the investigators have used various imaging approaches including radionuclide and ultrasound techniques to predict regions where function will recover after intervention. The results of these tests may be discordant because they assess separate attributes of cardiac muscle, and s ....After a heart attack, up to 50% of tissue showing reduced function can recover if blood supply is returned to normal with bypass surgery or balloon angioplasty. Because these procedures may be risky in cardiac patients, the investigators have used various imaging approaches including radionuclide and ultrasound techniques to predict regions where function will recover after intervention. The results of these tests may be discordant because they assess separate attributes of cardiac muscle, and selection of patients for intervention on the basis of recovery of regional function ignores some other aspects that may be important. These include avoidance of heart enlargement, improvement of exercise capacity, and avoidance of heart rhythm disturbances and even other heart attacks. In this study, the investigators seek to define the importance of the proportion and site of live (viable) myocardium to the parameters listed above. A new magnetic resonance technique will be used to identify whether radionuclide and ultrasound techniques assess different parts of the heart wall. The relative importance of these sites will be identified by comparing the outcome of patients who have live tissue in the inner half, compared with the outer half of the heart wall. This study will involve 180 patients who will undergo testing with magnetic resonance and radionuclide imaging. A subgroup will undergo dobutamine echocardiography. Their responses over follow-up will be assessed by accurate evaluation of heart size, exercise response, heart rhythm abnormalities and clinical events.Read moreRead less
Testing Of Vestibular Function By Active Head Movements.
Funder
National Health and Medical Research Council
Funding Amount
$180,509.00
Summary
The vestibular system of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture during head movements. This complex interdependent sensory system is comprised of three paired semicircular canals for sensing head rotations and two paired otolith organs for sensing head position and linear movements of the head. A major goal of our research programs is to develop simple tests which can be used in the clinic or at the bedside to diagnose specific d ....The vestibular system of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture during head movements. This complex interdependent sensory system is comprised of three paired semicircular canals for sensing head rotations and two paired otolith organs for sensing head position and linear movements of the head. A major goal of our research programs is to develop simple tests which can be used in the clinic or at the bedside to diagnose specific deficits of each vestibular sensory region. Most present clinical tests only test the part of the system concerned with horizontal head rotations but there are many other sensory regions in the inner ear whose functional status needs to be evaluated, especially those regions concerned with signalling linear head movements and head position - the otolith sensory regions. The usual principle in vestibular testing is to move the person's head and measure the eye movement which occurs in response to that passive movement. One of our recent observations suggest that it may be possible to measure vestibular functioning during active head movements. Active testing does not require expensive, invasive testing systems and could be carried out in the clinic. This project will compare the eye movement response to active and passive head movements in the same patients. We will test both the angular and linear sensing systems by asking patients to rotate their head or slide it laterally, recording the head movement stimulus and eye movement response. Two groups of patients will be studied; those who have recovered well and those who are poorly recovered after unilateral vestibular loss. The outcome will, we hope, be safe simple low cost tests which will evaluate the functional status of all the inner ear sensory regions and yet be clinically practical. They may provide the answer as to why some patients do not recover well after unilateral loss whereas others do.Read moreRead less