Fig. 8.

Stretch-induced ectopic activations

Epicardial activation in 6 rat left ventricles (as described in Fig. 6). For each heart an example of activation in response to sinus stimulation and stretch-induced ectopics are shown with the associated pseudo-ECG waveform. The amplitude of the sinus R-wave is given as a voltage reference. Sinus and ectopic type 1 activations spread rapidly while ectopic type 2 spread more slowly. Positive and negative going pseudo-ECG waveforms occur with both type of activation pattern. For each heart both ectopic types were taken from the same stretch (see Fig. 7). Varied activations within a single run of dilution-induced ectopics are common. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)