Effects of sympathetic nerve stimulation, right atrial pacing on myocardial metabolism and cardiac function in dog hearts with coronary constriction

73 EFFECTS OF SYMPATHETIC NERVE STIMULATION,RIGHT ATRIAL PACING ON MYOCARDIAL METABOLISM AND CARDIAC FUNCTION IN DOG HEARTS WITH CORONARYCONSTRICTION. R.Sato, S.Yoshida, K.Ohno, K.Nohara, N.Ishiyama and O.Iimura. 2nd Dept. of Internal Medicine,Sapporo Medical College,Sapporo,Japan. In order to clarify the effect of cardiac sympathetic nerve activity on myocardial metabolism and cardiac function in global ischemic heart,stimulation of left stellate ganglion(SNSt,4HZ,lOV) and right atria1 pacing( RAP,5V,maximal rate without A-Vblock) were performed in the dogs,of which left main coronary artery was cannulated with Griggs type cannula.In the dogs with coronary blood flow reduced by 35% of control level,SNSt significantly augmented the ischemic change in ECG,elevated LVEDP,and myocardial G-6-P,F-6-P,lactate and a-GP,and decreased ATP and CP,especially in subendocardial myocardium.RAP increasedacardiac work but not remarkably changed myocardial metabolism.Thus,it is suggested that myocardial ischemia might be augmented by sympathetic nerve activity and this augmentation might be partly related to a reduction of PFK activity.

COMPARATIVE STUDY OF PLASMA CATECHOLAMINE CHANGES DURING VARIOUS EXERCISES. H. Kanda, T. Haneda, T. Arai, K. Shirato, Y. Koiwa, T. Nakajima, M. Kanazawa, K. Ishikawa, M. Ohe, R. Hashiguchi, T. Mimata and T. Takishima. The 1st Dept. of Int. Med., Tohoku University School of Medicine, Sendai, Japan In order to compare the sympathetic activities during various exercises, plasma catecholamine (CA) levels were measured in 29 subjects undergoing cardiac catheterization. All subjects had normal left ventricular (LV) function curve assessed by exercises. Exercises were performed as follows; 1. Isometric handgrip -10 patients, 30% of maximum voluntary contraction for 3 min. 2. Bicycle ergometer - 9 patients, 50 watt of leg exercise for 5 min. 3. Right 120 bpm of heart rate induced atria1 pacing-10 patients, by pacing for 5 min. The percent changes of CA significantly correlated with those of LV minute work which were calculated from aortic mean systolic pressure and cardiac index (r=0.762, p
mented plasma CA is related work during in subjects

to the increment

either isometric exercise with normal LV function.

of cardiac

or dynamic

exercise