T-Q, S-T segment mapping and hyperemia in reperfused pig heart with ischemic preconditioning.
The effects of ischemic preconditioning on epicardial T-Q and S-T segment mapping, local activation, and coronary blood flow were analyzed in nine barbiturate-anesthetized pigs during four coronary occlusion (5 min)-reperfusion (20 min) sequences. In seven sham pigs, one occlusion was performed after a control period of 75 min. The first reperfusion induced a marked coronary hyperemia [11 +/- 4 ml/min (baseline) to 33 +/- 16 ml/min, P < 0.005] and a rapid recovery (30 to 150 s) of epicardial activation delays, T-Q segment depression, and S-T segment elevation in the ischemia area. This recovery was transiently associated with enlargement of intersite T-Q potential variability (alpha: 2.5 +/- 0.6 to 3.4 +/- 0.7 mV, P < 0.05), T-Q segment overshoot to +1.4 +/- 0.9 mV, and S-T segment reelevation. A brief T-Q segment depression (-2.3 +/- 0.9 mV) occurred during early reperfusion in 60 of 91 electrodes overlying the normal myocardium. Compared with the first, the fourth occlusion induced lower S-T segment elevation (3.4 +/- 2.0 to 1.7 +/- 1.9 mV, P < 0.05), and the fourth reperfusion elicited a faster reversal of T-Q segment dispersion (53 +/- 21 to 43 +/- 16 s, P < 0.05), S-T segment elevation (149 +/- 101 to 81 +/- 45 s, P < 0.05), and coronary hyperemia (8 +/- 2 to 5 +/- 1 min, P < 0.05). This trend of changes was not observed during a fourth occlusion in sham pigs.(ABSTRACT TRUNCATED AT 250 WORDS)
Cinca
J
J
Laboratorio de Cardiologia Experimental, Hospital Universitari Vall d'Hebrón, Barcelona, Spain.
Worner
F
F
Carreño
A
A
Coronel
R
R
Soldevilla
A
A
Pérez-Villa
F
F
Janse
M J
MJ
Soler-Soler
J
J
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology; D003213:Conditioning, Psychological; D003326:Coronary Circulation; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology*; D004562:Electrocardiography; D004594:Electrophysiology / Q000379:methods*; D006321:Heart / Q000503:physiopathology*; D006940:Hyperemia / Q000209:etiology* / Q000503:physiopathology; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury; D013552:Swine; D013997:Time Factors