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Imaging
Past, Present and Future of Stress Echocardiography –
How Far Have We Come and How Far Can We Go?
a report by
Nithima Chaowalit
1
and Patricia A Pellikka
2
1. Division of Cardiology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok;
2. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
How Far Have We Come? American Society of Echocardiography (ASE).
5
Additional information,
Cardiac imaging using ultrasound (so-called ‘echocardiography’) was such as a change in LV volume during stress, provides additive value with
introduced more than 50 years ago. Resting echocardiographic respect to accuracy and prognosis.
detection of myocardial infarction was described as the reduction in
regional contractile function,
1
and the development of stress Exercise remains the prototype for stress testing in the diagnosis of
echocardiography in the early era was recognised after the CAD. It was the first stress modality to be combined with
introduction of 2D echocardiographic imaging. The initial report in echocardiography and remains popular in clinical practice. The very
1979 by Wann et al. demonstrated the value of 2D echocardiography first reports of stress echocardiography dealt with the use of M-mode
in identifying exercise-induced wall motion abnormalities.
2
During the echocardiography with exercise in normal subjects
6
and in patients
early days of stress echocardiography, problems included imaging with CAD.
7
Subsequently, 2D echocardiography was introduced to
quality and techniques. For evaluating patients with known or detect exercise-induced ischaemic wall motion abnormalities.
2
Exercise
suspected coronary artery disease (CAD), there was also the need to echocardiography can be performed using a treadmill or a bicycle. The
establish equivalent accuracy and prognostic values to the well- most commonly employed form of exercise echocardiography involves
established alternative imaging technique, stress radionuclide immediate imaging after treadmill use. Images are acquired at rest as
myocardial perfusion imaging. The acquisition of stress a baseline for comparison and either immediately after treadmill
echocardiographic imaging initially involved continuous videotape exercise or during various levels of bicycle exercise. It is possible to
recording for sequential evaluation of wall motion; the development of obtain additional Doppler data during bicycle exercise; this test may
the digital acquisition system for the side-by-side comparison of rest also be used for assessing valvular heart disease or exertional changes
and post-stress imaging was a major advance. in diastolic function. Data regarding haemodynamic response to
exercise, exercise capacity and arrhythmias have also added useful
Early studies of stress echocardiography employed exercise as a stressor diagnostic and prognostic information and should be included in the
and were mostly feasibility studies.
2–4
Any form of physical exercise that report. Ischaemic threshold and the heart rate or percentage of target
provides an appropriate increase in heart rate and cardiovascular heart rate at which ischaemia first occurs can be obtained from bicycle
workload can be used in the performance of exercise echocardiography. exercise but not from treadmill exercise.
However, the technique of exercise echocardiography is challenging in
terms of image acquisition during physical exercise (either on a treadmill Pharmacological stress echocardiography is an alternative in patients who
or on a bicycle). Furthermore, the feasibility of exercise echocardiography are unable to exercise or when assessment of viable myocardium is an
is limited in patients who are unable or unwilling to exercise, or when issue. Among pharmacological stress agents, dobutamine and
myocardial viability is an important issue. This led to the development dipyridamole are popular. Dobutamine provides a balanced inotropic and
of various forms of pharmacological and other non-exercise stressors chronotropic response, and has become the most commonly utilised
(see Table 1). pharmacological stressor. Images are acquired at baseline and during
The advent of offline digital handling for data acquisition, storage,and
Nithima Chaowalit is an Assistant Professor of Medicine
display, further improvements in echocardiographic imaging techniques
and an echocardiologist in the Division of Cardiology of
and the development of a wide variety of stressor modalities contributed
the Department of Medicine at Siriraj Hospital, Mahidol
to rapid growth in the field of stress echocardiography.
University. She worked with Dr Pellikka as a Research
Fellow in the field of stress echocardiography at Mayo
Clinic, Rochester.
Methodology
Images are acquired in multiple views at baseline and at varying stages
during stress and/or recovery. Representative images are then displayed
Patricia A Pellikka is a Professor of Medicine at Mayo
in a side-by-side format for the comparison of either various stages of
Clinic College of Medicine. She is also Co-Director of the
the same echocardiographic view or individual views at each stage of Echocardiography Laboratory and Director of the
stress. Regardless of the stressors, the echocardiographic detection of
Echocardiography and Vascular Physiology Research Unit
at Mayo Clinic. She was responsible for introducing stress
inducible ischaemia as new or worsening wall motion abnormalities
echocardiography into clinical practice at Mayo Clinic.
remains the hallmark of the positive test result for the diagnosis of CAD.
E: pellikka.patricia@mayo.edu
The wall motion abnormalities can be matched to the standardised
multisegment left ventricular (LV) model, as recommended by the
© TOUCH BRIEFINGS 2008 53
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