VT stimulation in rats

Under continuous ECG-recording, PES is performed from the RV outflow tract, with the use of a miniature bipolar hook-electrode, kindly provided by Professor Yoram Etzion (Ben-Gurion University of the Negev, Israel).
The PES-protocol includes up to three extrastimuli (ES) after a basic-drive of 20 paced beats at a cycle-length of 100ms. No distinction is made between ventricular tachycardia and ventricular fibrillation.
As an end-point, we use a validated arrhythmia-score, as shown below.