| abstract |
The method for collecting cardiac activity data non-invasively from the chest or thorax of a patient comprises the steps of: n placing at least three active Laplacian ECG sensors at locations on the chest or thorax of the patient; n placing at least one ultrasonic sensor on the thorax where there is no underlying bone structure, only tissue, and where the ultrasonic sensor can transduce signals directly from the heart for measuring the time a burst of sound travels to and from the moving surface of the heart; n assuming the velocity of ultrasound propagation to be constant in the tissues involved; n making direct measurements of the exact sites of the sensors on the chest surface to determine the position and distance from the center of the sensor to the heart along a line orthogonal to the plane of the sensor to create a virtual heart surface; n updating the measurements at a reasonable rate to show the movement of the heart's surface; n monitoring at each ultrasonic sensor site and each Laplacian ECG sensor site the position and movement of the heart and the depolarization wave-fronts in their vicinity; n treating those depolarization wave-fronts as moving dipoles at those sites to mimic time dependent charges or dipoles at those sites, equivalent to moving charges or dipoles on the heart; and, n displaying the heart activity like a moving picture which is equivalent to an approximation of the activation sequence on the virtual surface of the heart, n thereby to create chest surface maps of isochrones and the projections of those of isochrones onto a virtual surface that represents the heart, which can indicate the simultaneously depolarized zones for detecting zones of delayed depolarization, such as areas which have suffered infarctions and correlating those delayed zones with the movement and shape of the heart, n or thereby to create Laplacian isopotential maps either on the chest surface or their projection onto a virtual heart surface. |