[10-day clinical course of a stunned myocardium model with very short and repeated ischemias].
OBJECTIVE
In previous studies we have observed ischemic processes of very brief duration (2 minutes) and with brief reperfusion (3 minutes), which have been repeated 20 times (ischemic protocol [IP]). They are capable of producing contractile dysfunction of the ischemic zone, with a decrease of 28.6% at 24 hours, and coronary blood flow maintenance (stunning).


METHODS
The aim of this study is to examine the evolution of this dysfunction. The IP designed in our laboratory was used on 24 adult mongrel dogs. We measured regional myocardial function using a pair of implanted chronic ultrasonic crystals in the ischemic area (depending on the left anterior descending coronary artery) and a second pair in the control zone (depending on the left circumflex coronary artery).


RESULTS
After analyzing results, we found that the shortening fraction decreased to 28.6% (p < 0.05) in 24 hours. During the subsequent five days the shortening fraction decreased to a minimum of 67.88% (p < 0.01), after which there was a progressive recovery that reached 18.95% (NS) below the base-line on the tenth day. We did not observe any significant variation in the hemodynamic parameters at any time.


CONCLUSIONS
The repeated, very brief episodes of ischemia (in the experimental terms that we have explained) produced a contractile dysfunction which reached its maximum on the fifth day, and returned to normal on the tenth day. We hypothesize that these alterations could explain the episodes of left ventricular failure with spontaneous recuperation observed in stable myocardial ischemia, and for which no immediate cause has been found.
Pallarés Carratalá
V
V
Unidad Cardiocirculatoria, Hospital Universitario La Fe, Valencia.
Hernándiz Martínez
A
A
Cosín Aguilar
J
J
Portolés Sanz
M
M
Capdevila Carbonell
C
C
Pomar Domingo
F
F
Andrés Conejos
F A
FA
D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D008297:Male; D017202:Myocardial Ischemia; D017682:Myocardial Stunning / Q000503:physiopathology*; D013997:Time Factors
Evolución a lo largo de 10 días de un modelo de miocardio aturdido mediante isquemias muy breves y repetidas.