A Study of the Cumulative Effect of the Postischemic Prolonged Myocardial Dysfunction by Repeated Coronary Artery Occlusion and Reperfusion.
10.4070/kcj.1991.21.3.518
- Author:
Cheol Ho KIM
;
Byung Woo YOON
;
Byung Hee OH
;
Myoung Mook LEE
;
Young Bae PARK
;
Jung Don SEO
;
Young Woo LEE
- Publication Type:Original Article
- MeSH:
Animals;
Blood Pressure;
Coronary Occlusion;
Coronary Vessels*;
Dogs;
Myocardial Ischemia;
Relaxation;
Reperfusion*;
Repetitive Sequences, Nucleic Acid
- From:Korean Circulation Journal
1991;21(3):518-530
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
In order to observe the changes in left ventricular systolic and diastolic function by repetitive regional myocardial ischemia and reperfusion, left anterior descending artery(LAD) just distal to the first diagonal branch in nine mongrel dogs was obstructed for 1 minute and reperfused for 15 minutes twice (first and second obstruction and reperfusion), and as a third trial repeated obstruction for 5 minutes and reperfusion for 15 minutes was done. Then the last obstruction for 1 minute and reperfusion for 15 mintues was performed. Peak positive dp/dt, left ventricular systolic pressure(LVSP) and systolic thickening were used as systolic parameters and peak negative dp/dt, left ventricular end diastolic pressure (LVEDP) and time constant of isovolumic relaxation were used as diastolic parameters. The results are as follows : 1) After first reperfusion, all systolic and diastolic parameters showed no significant changes except systolic thickening, which fell from the basal line(48.9+/-16.6% versus 59.8+/-10.0%, p<0.05). 2) After second reperfusion, peak positive dp/dt and systolic thickening decreased (1475+/-342mmHG/sec versus 1561+/-307mmHg/sec,p<0.05; 48.2+/-6.1% versus 59.8+/-10.05%, p<0.005 respectively). But LSVP, LVEDP, peak negative dp/dt and T showed no significant changes. 3) After third reperfusion all systolic and diastolic parameters except LVEDP showed significant impairment by 5 minutes of coronary occlusion, which means postischemic prolonged myocardial dysfunction(peak positive dp/dt 1401+/-362mmHg/sec versus 1561+/-307mmHg/sec, p<0.005; LVSP 88.5+/-23.4mmHg versus 97.6+/-25.4mmHg, p<0.05; systolic thickening 41.2+/-8.2% versus 59.8+/-10.0%, p<0.005; peak negative dp/dt -879+/-299mmHg/sec versus -1037+/-297mmHg/sec, p<0.05; T 46.3+/-8.2 msec versus 41.9+/-6.1 msec, p<0.01). 4) All observed systolic and diastolic parameters also revealed myocardial dysfunction after fourth reperfusion(peak positive dp/dt 1348+/-288mmHg/sec versus 1561+/-307mmHg/sec, p<0.0005; LVSP 88.5+/-24.1mmHg versus 97.6+/-25.4mmHg, p<0.005;systolic thickening 32.1+/-8.9 versus 59.8+/-10.0%, p<0.001; peak negative dp/dt -850+/-260mmHg/sec versus -1037+/-297mmHg, p<0.05; LVEDP 6.6+/-1.7mmHg versus 5.4+/-1.3mmHg, p<0.05; T 49.9+/-9.8msec versus 41.9+/-6.1msec, p<0.01). 5) Overall tendencies of myocardidal impairment were statistically significant in each parameter (peak positive dp/dt, p<0.001; systolic thickening, p<0.05; LVEDP, p<0.05; T, p<0.01) except LVSP and peak negative dp/dt. Thus myocardial function was impaired progressively by repetitive regional myocardial ischemia and reperfusion. In conclusion, a 5 minute coronary occlusion results in postischemic prolonged myocardial ischemia and repetitive coronary occlusion and reperfusion may show cumulative effect.
