Myocardial ischemic preconditioning during minimally invasive direct coronary artery bypass grafting attenuates ischemia-induced electrophysiological changes in human ventricle.
OBJECTIVE
Ischemic preconditioning (IPC) has been found to protect the myocardium in animal studies. However, clinical studies have been limited and the clinical effects of IPC are still uncertain. The purpose of this study was to assess whether IPC has any protective effect on the human myocardium during minimally invasive CABG (MIDCAB), by means of epicardial electrophysiological testing.


METHODS
Forty-five patients with left anterior descending artery disease who underwent a MIDCAB procedure were evaluated. In the present study, the electrical potentials which were not affected by cardio-pulmonary bypass or cardioplegia were measured. The ratio of longitudinal to transverse conduction velocity (phiL /phiT), and QT, JT dispersions were measured using plaque electrodes in the preischemic state, during a 5-minute coronary occlusion, during the subsequent 5-minute reperfusion, during 5- and 10-minute anastomosis periods, and after anastomosis.


RESULTS
The phiL/phiT was 2.2 +/- 0.2 at baseline. Anisotropy was exaggerated during the 5-minute coronary occlusion (2.6 +/- 0.3). During anastomosis, conduction velocities were decreased, but showed no further deterioration (2.4 +/- 0.3, and 2.4 +/- 0.3, respectively). QT and JT dispersions were improved by reperfusion.


CONCLUSIONS
The effectiveness of IPC during the MIDCAB procedure was confirmed electrophysiologically. Anisotropy and dispersions were minimized after IPC, therefore IPC demonstrated antiarrhythmic protective effects on the human myocardium.
First Department of Surgery, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan.
Yoshio
Y
Doi
Go
G
Watanabe
Keiju
K
Kotoh
Katsushi
K
Ueyama
Takuro
T
Misaki
D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001026:Coronary Artery Bypass; D005260:Female; D006321:Heart / Q000502:physiology; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures