Description:
The most common tool for cardiac screening and diagnosis, the electrocardiogram (ECG) is at best an indirect measure of cardiac dimensions. Specific dimensions of interest including chamber volumes, wall thickness and septal thickness can only be indirect assessed by ECG with overall poor predictive value for these measurements. Historically the ECG has achieved widespread clinical application because of its ease of use and relatively low cost, even though it fails to accurately reflect chamber size and wall thickness. The ECG does provide important information on heart rhythm, possible ischemia, infarction and other electrophysiological abnormalities. While the echocardiogram (echo) does directly reflect chamber size and wall thickness, traditional echo systems are costly and bulky, require a highly trained technician and yield results with high dependence upon operator skill and experience. Therefore, a device is needed that provides the low cost, compact size, ease of use and simple output format of ECG and its electrophysiologic information, combined with automated quantitative volume and dimensional information available from echo. Such a system would eliminate inaccurate analysis of the ECG wave forms for chamber size and hypertrophy. The device would also alleviate the need for a highly trained technician. These advantages would cause the proposed device to replace nearly all standard electrocardiographs.
The current invention describes a combined ECG-echo system that encompasses the advantage of each technology to optimize cardiac diagnosis and monitoring. The invention incorporates a conventional multi-lead diagnostic ECG where one or more leads are replaced by a combined ECG lead and low profile ultrasound transducer. In addition, the invention includes an automated ultrasound data acquisition and processing unit to extract dimensional and volumetric information from acquired ultrasound data (and displays such information in a graphical format along with traditional ECG plots).
The present invention yields the electrophysiological measurement functions of an ECG — while at the same time performing highly accurate measurements of cardiac chamber volumes, wall and septal thicknesses, and other geometric measures — in a low-cost, portable, easy-to-use device. While some of these functions may exist in different current products, their combination yields a more powerful tool for the diagnosis, screening and monitoring of cardiac conditions. This device would set the new standard for "electrocardiographs," and potentially every machine would be converted. Additionally, this technology would be applicable to real-time monitoring in ICU's (continuous ejection fraction and cardiac size) and potential ambulatory monitoring of cardiac hypertrophy and enlargement, as well as function.
