Technical Development of Strain Rate Echocardiography

Overview

This study will examine heart function using two imaging techniques - echocardiography (ultrasound) and magnetic resonance imaging (MRI) - to evaluate newly developed software for echocardiograph machines. MRI and ultrasound both provide images of the heart structure and function. MRI uses a magnetic field and radio waves to obtain the pictures, while echocardiography uses sound waves. Patients with any form of heart disease and healthy volunteers 21 years of age and older may be eligible for this study. Candidates must be and able to undergo magnetic resonance imaging and must not have an irregular heart rhythm, heart valve disease, a pacemaker, defibrillator implant, insulin pump, or other metallic implant. Participants will have two ultrasound examinations and two magnetic resonance imaging examinations, as described below. All the tests will be completed within 24 to 48 hours. Echocardiography : For this test, a small probe is passed over the chest. Sound waves emitted from the probe bounce off the heart and are beamed back into the echo machine where they are recorded. The sonographer does a baseline test, which is evaluated by the physician. Then, after a 10- to 20-minute break, portions of the test are repeated. The entire exam takes about 2 hours. Magnetic Resonance Imaging: For MRI, the subject lies on a table that slides into a long doughnut-shaped scanner. A small tube is placed in a vein in the hand or arm to give fluids and to infuse gadolinium, a contrast material that brightens the images. Heart rate and blood pressure are monitored during the study, which takes about 3 hours.

The purpose of this protocol is to study the reproducibility of strain rate (SR) echocardiography in normal volunteers and patients with cardiovascular disease. Tissue Doppler ultrasound is a technology which has been validated for the analysis of global and regional left ventricular function and strain and SR measurements are derived from tissue Doppler imaging (TDI) data. Over the last few years, several improvements in echo machine hardware and software have facilitated the rapid acquisition and analysis of tissue Doppler data, and therefore, strain and strain rate information has become easily accessible. Recent publications have demonstrated the usefulness of these techniques in the analysis of systolic and diastolic function of the left ventricle, and in the detection of regional wall motion and ischemia. Several protocols recently initiated in the Cardiovascular Branch involve echocardiographic imaging and include applications of TDI as their primary or secondary endpoints. Therefore, the purpose of this protocol is to allow development of standardized acquisition and analysis methods of TDI for our cardiology protocols and to evaluate the reproducibility of TDI, SR, and strain measurements.