ejection period and ejection time that 

 Gigi does (Weissler et al.. I960; 

 Leighton et al.. 1971). 



We said that the Beg is used to 

 estimate cardiac function. This is 

 possible because of the close relation- 

 ship between the acceleration Beg and 

 the acceleration of blood out of the 

 left ventricle into the aorta (Winter 

 et al.. 1966, 1967: Smith. Van Citters, 

 and Verdouw. 1970; Deuchar. 1966). 

 The latter is a proven sensitive indi- 

 cator of cardiac function (Noble. 

 Trenchard. and Guz. 1966; Noble, 

 Gabe. and Trenchard. 1967; Rushmer. 

 1964. 1970). 



Gigi's stroke index of 1.6 ml/kg 

 is somewhat greater than that of man. 

 about 1 ml/kg. However, since the 

 heart rate was slower in Gigi, the 

 cardiac index was closer to that of 

 man (Table 1). Again, in comparing 

 several species, we note that when 

 cardiac output is plotted against body 

 weight on a log-log scale, a straight 

 line is obtained (Altman and Dittmer, 

 1971, p. 320). It does seem reason- 

 able that stroke inde.x is roughly 

 equivalent in different mammals, since 

 the heart/body mass ratios are similar. 



Although the measurement of 

 acceleration, as opposed to displace- 

 ment or velocity, minimizes the in- 

 fluence of ventilation, any movement 

 or muscular activity can disturb the 

 recording. Since whales must expire 

 and inspire rapidly between dives, 

 the muscular activity is relatively 

 violent. As Wahrenbrock has 

 measured. Gigi's peak instantaneous 

 flow rate was 285 1/sec. Thus 

 ventilation demolished Gigi's Beg 

 recording. Fortunately, ventilatory 

 rate was extremely slow so that the 

 Beg had sufficient time to recover 

 between breaths. 



The Beg has now been recorded 

 in a wider range of masses in animals 

 than any other physiologic test. The 

 mass ratio is 1;6, 000.000. egg embryo: 

 whale. This points out the versatility 

 of the Beg and suggests its importance 

 as a technique for comparative 

 physiological and pharmacological 

 studies. 



ACKNOWLEDGMENTS 



The authors wish to acknowledge 

 the invaluable assistance of Gary 

 Maruschak. They also thank the 

 staff of Sea World who participated 

 in this study. Without their enthusi- 

 astic cooperation, these studies would 

 have been impossible. 



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MFR Paper 1046. From Marine Fisheries Review, Vol. 

 36. No. 4. April 1974. Copies of this paper, in limited 

 numbers, are available from D83. Technical Informa- 

 Division. Environmental Science Information 



tion 



Center. NOAA. Washington. DC 20235. 



14 



