Origin of ischemia-induced phase 1b ventricular arrhythmias in pig hearts
Ruben Coronel, MD, PhD*,*,
Francien J. G. Wilms-Schopman, MSc and
Joris R. deGroot, MD, PhD*
* Experimental and Molecular Cardiology Group, Cardiovascular Research Institute, Academic Medical Center, Amsterdam, The Netherlands
Interuniversity Cardiology Institute, Utrecht The Netherlands
View larger version (20K):
[in a new window]
|
Figure 1 Average arrhythmias in 5-min bins after coronary occlusion (t = 0) in the three models used (A, B and C). Drawn line indicates number of surviving animals. Number of ventricular premature beat (VPBs) divided by 10. VF = ventricular fibrillation; VT = ventricular tachycardia.
|
|
View larger version (14K):
[in a new window]
|
Figure 2 Top: Hearts grouped according to the most severe arrhythmia in the 1b phase. Bottom: Number of first ventricular premature beat (VPBs) corrected for the differences in observation time. VF = ventricular fibrillation; VT = ventricular tachycardia.
|
|
View larger version (53K):
[in a new window]
|
Figure 3 Pressure recording from the intraventricular balloon (19 min after occlusion). Left ventricular (LV) and right ventricular (RV) bipolar electrograms show ventricular premature beats after the postpause activation.
|
|
View larger version (43K):
[in a new window]
|
Figure 4 Top: Electrogram of the onset of ventricular fibrillation 21 min after occlusion. The shaded area (diagram) designates ischemic tissue; the pulse shows the site of stimulation. Dots in the enlarged multi-electrode represent electrode positions; the circle represents the site of focal origin. The dotted line indicates the electrophysiological border. A, B and C are activation maps of the corresponding beats. Lines indicate 5 ms isochrones; arrows indicate gross activation sequence; numbers indicate times relative to the last stimulus artefact; the asterisk indicates the site of origin. Note the absence of R wave in local electrogram recorded from the site of origin (top).
|
|
View larger version (23K):
[in a new window]
|
Figure 5 (A) Number of foci (in situ experiments) in 5-mm bins distance from the electrophysiological border (0 mm). Negative values indicate the ischemic side. Dotted lines indicate the border region. (B) Number of foci (all experiments) inside and outside the border region.
|
|
View larger version (36K):
[in a new window]
|
Figure 6 Top: Electrograms (recorded from marked sites) 26 min after occlusion. Activation map from the ventricular premature beat shows two foci (asterisks). Details as in Figure 4.
|
|
View larger version (41K):
[in a new window]
|
Figure 7 Top: Electrograms of a short run of ventricular tachycardia 26 min after occlusion. Activation maps are of subsequent beats. Details as in Figure 4. The first and second beats have a focal origin (A and B, circles in middle left panel) close to the border. No R waves occur at the sites of origin (see electrograms).
|
|
View larger version (24K):
[in a new window]
|
Figure 8 Example of the time course of relative rise of tissue impedance (Rt) in an isolated perfused heart and a heart in situ (top). Both electrodes are from the central ischemic zone and displayed a more than twofold rise in absolute Rt. 100% indicates the value at 90 min of ischemia. Bottom: Onset, time of maximum rise and time of 95% rise of Rt compared between isolated hearts and in situ hearts.
|
|
|
