As a cardiologist, I am often faced with the challenge of selecting between available tests of heart function. We always want to help each patient in the best way possible. The information gained from each cardiac test is somewhat overlapping, however certain tests may uniquely provide better information to answer a specific question that is most relevant to a particular patient. A 2D echo, or ultrasound of the heart, is often the best place to start, since an echo shows global heart function, including the function of each muscle segment, and each of the four valves. An echo readily identifies anomalous structures or congenital abnormalities which otherwise wouldn’t be appreciated. Even when advanced imaging is required, it is wise to first perform a 2D echo, so the unique contribution of the advanced study is best appreciated.
There are a variety of stress tests which may be performed. The simplest is a treadmill stress test with ECG monitoring. This is used to assess the exercise capacity of the patient, and to reproduce symptoms that are known to occur with exercise, while heart rhythm and blood pressure monitoring are being performed. Furthermore, ECG changes that may occur when chest pain is due to blockages in the arteries to the heart (coronary arteries) may be revealed. The next level of stress testing includes imaging, which is used to assess for the presence of coronary artery disease causing blood flow limitation during exertion. Imaging used with stress testing may be a 2D echo performed at peak exertion during a treadmill stress test or with medication (dobutamine) used to stress the heart. This is called a stress echo. The second imaging modality that is frequently used is myocardial perfusion imaging (MPI), where a nuclear tracer is injected and used to image blood flow patterns to the heart both during rest and during a stress state.
To summarize: A 2D echo, performed in isolation, provides different information than a stress test. Either test may be used depending on the information needed. It is common to obtain a 2D echo prior to any stress test, to provide a baseline assessment of global heart function. When 2D echo is used with stress testing, the echo is performed both during rest and stress, with images compared to visualize contraction abnormalities which may develop due to underlying obstructive coronary artery disease that becomes evident during stress or exertion.