Stress echocardiography

Stress echocardiography is echocardiography done when the heart is under stress with exercise or medications. Echocardiography is imaging of the heart using ultrasound waves. An ultrasound beam is transmitted for a fraction of a second and the echoes received from the heart are analyzed by the device computer. The analyzed signals are used to give an image of the inner structure of the heart. Repeated pulses are given from the device and echoes recorded sequentially and displayed on the monitor screen. Continuous display gives a real time imaging of the functioning of the heart, its various chambers and valves.

Technical aspects of stress echocardiography

In certain conditions like partial narrowing of the blood vessels of the heart, the function of the heart may be normal at rest, but becomes abnormal with exercise or any other forms of stress. Real time imaging of the heart during exercise by echocardiography is difficult due to movement artefacts. Hence stress echocardiography is usually done with other forms of stress to the heart, typically by increasing the heart rate by medications.

Medications like dobutamine can be given as a continuous drip and echocardiography done simultaneously. As the heart rate increases with increasing dosage of the medication, parts of the heart with low blood supply show abnormal motion. This is documented by stress echocardiography. Stress echocardiography is also useful in studying heart function in those who are unable to do exercise. Inability to exercise could be due to physical disability or abnormality of lung function.

Stress echocardiography is a good test to document reduced blood supply to regions of the heart. But, it is not done routinely in most centers. This is due to constraints of time and logistic difficulties. These include arranging drip sets and other emergency care equipment within the limited space of a usual echocardiography room.