The ischemic preconditioning effect of adenosine in patients with ischemic heart disease.
BACKGROUND
In vivo and in vitro evidence suggests that adenosine and its agonists play key roles in the process of ischemic preconditioning. The effects of low-dose adenosine infusion on ischemic preconditioning have not been thoroughly studied in humans.


OBJECTIVE
We hypothesised that a low-dose adenosine infusion could reduce the ischemic burden evoked by physical exercise and improve the regional left ventricular (LV) systolic function.


METHODS
We studied nine severely symptomatic male patients with severe coronary artery disease. Myocardial ischemia was induced by exercise on two separate occasions and quantified by Tissue Doppler Echocardiography. Prior to the exercise test, intravenous low-dose adenosine or placebo was infused over ten minutes according to a randomized, double blind, cross-over protocol. The LV walls were defined as ischemic if a reduction, no increment, or an increment of < 15% in peak systolic velocity (PSV) was observed during maximal exercise compared to the baseline values observed prior to placebo-infusion. Otherwise, the LV walls were defined as non-ischemic.


RESULTS
PSV increased from baseline to maximal exercise in non-ischemic walls both during placebo (P = 0.0001) and low-dose adenosine infusion (P = 0.0009). However, in the ischemic walls, PSV increased only during low-dose adenosine infusion (P = 0.001), while no changes in PSV occurred during placebo infusion (P = NS).


CONCLUSIONS
Low-dose adenosine infusion reduced the ischemic burden and improved LV regional systolic function in the ischemic walls of patients with exercise-induced myocardial ischemia, confirming that adenosine is a potential preconditioning agent in humans.
Sadigh
Bita
B
The Karolinska Institute, Department of Cardiology, Karolinska University Hospital, Huddinge, Stockholm, Sweden. bita.sadigh@karolinska.se
Quintana
Miguel
M
Sylvén
Christer
C
Berglund
Margareta
M
Brodin
Lars Ake
LA
D000241:Adenosine / Q000008:administration & dosage*; D000368:Aged; D001794:Blood Pressure; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015150:Echocardiography, Doppler; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D007262:Infusions, Intravenous; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008875:Middle Aged; D016277:Ventricular Function, Left / Q000187:drug effects
D000241:Adenosine