Cardiac activation mapping in a transgenic mouse model of cardiac hypertrophy

Genetically altered mice have been developed to study many aspects of cardiac membrane electrophysiology. Observations made at the cellular level in these transgenic mice are often not correlated with the ECG from the intact animal. Transgenic (N=4) and control (N=4) mice were studied with hardware and software tools developed to observe epicardial activation. A custom probe mapped the anterior right ventricle using 16 unipolar electrodes arranged in a 4x4 matrix (1.0 mm(2)). Labview software controlled the digitization, storage and real time display of the signals. With Matlab programs, local activation times were identified, and isochronous maps and spacial velocity vectors were constructed. The direction of the activation wavefront shifted 90 degrees in the transgenic mice when compared to the central group. Such changes in the conduction patterns may help demonstrate macroscopic conduction abnormalities resulting from cellular communication differences in the genetically altered mice as compared to control mice.