Hands-Free Continuous Echocardiography during Treadmill Exercise Using a Novel Ultrasound Transducer

Background: Echocardiographic imaging using a handheld transducer in conjunction with treadmill exercise testing is commonly used for the diagnosis of coronary artery disease. Motion of the hand and the transducer during peak exercise preclude optimal imaging. To circumvent the limitations of handheld transducers, we developed a low profile transducer (CONTISON) which can be attached to the chest wall for continuous cardiac imaging. Methods and Results: This feasibility study was performed in 10 normal male subjects (28 to 36 years). The ultrasound transducer was placed in the third or fourth intercostal space at the left sternal border to permit imaging of the left ventricle in its short axis. The transducer was interfaced with a commercially available ultrasound machine. The left ventricle was imaged at rest and while subjects exercised according to a standard Bruce protocol. All segments of the left ventricular short axis were seen at rest and peak exercise. Increased left ventricular wall thickening and wall motion were seen at peak exercise. There were no complications from the procedure. Conclusion: We demonstrated the feasibility of hands-free left ventricular imaging during treadmill exercise using the CONTISON transducer. Further evaluation of the technique to detect stress-induced wall motion abnormalities, as a means of diagnosing myocardial ischemia, appears warranted. (ECHOCARDIOGRAPHY 2010;27:563-566).