Effects of low calcium reperfusion and adenosine on diastolic behavior during the transitory systolic overshoot of the stunned myocardium in the rabbit.

GERMAN GONZALEZ; MANUEL RODRIGUEZ; MARTIN DONATO; JIMENA PALLEIRO; VERONICA DANNUNZIO; CELINA MORALES; RICARDO J GELPI

CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY

NRC Research Press

Lugar: Ottawa; Año: 2005 p. 1 - 1

0008-4212

The aim was to determine if the transitory systolic overshoot (TSO) that occurs in the early reperfusion (R) of the stunned myocardium is accompanied by diastolic alterations, and determine if the R with low Ca2+ Krebs-Henseleit’s solution or with adenosine modifies these alterations. Isolated–isovolumic rabbit hearts were divided in 3 groups (G). G1 (n=11) was perfused with Krebs-Henseleit´s solution, subjected to 15 min of global ischemia and 30 min R; G2 (n=10) was reperfused during the first 10 min with Krebs-Henseleit´s solution [Ca2+]=1mM, which was increased in the perfusate to 1.5 mM up to 20 min R and at 2.5mM from 20 to 30 min R. G3 (n=12) was perfused with Krebs-Henseleit´s solution with adenosine (0.03 ìg/kg/min) from 10 min before ischemia and during all R. Left ventricular (LV) +dP/dtmax (mmHg/sec), LV end diastolic pressure (LVEDP, mmHg), and one relaxation index (t1/2) were measured, in preischemic state, at 30, 50, 60, 70, 90 and 120 sec R, and then at 5 and 30 min R. The +dP/dtmax recovered to 621±77 mmHg/sec (p=NS), 346±31 mmHg/sec (p<0.05 vs G1) and 533±76 mmHg/sec (p=NS) from preischemic value of 730±39, 690±32 and 758±57 in G1, G2 and G3 respectively. The LVEDP in G1 and G3 increased early in the R, and it was negatively correlated with the +dP/dtmax (r=-0.63; p=0.0369 and r= -0.71; p=0.0090 respectively). The R with low Ca2+ abolished this correlation and attenuated the TSO phase. The correlation between LVEDP and +dP/dtmax in G1 and G3 and the lack of correlation in G2 suggests there are common mechanisms for the systolic and diastolic alterations during the TSO phase which are possibly related to Ca2+ overload but not with the vascular tone.