ECG -n 



ULFBcq^ 



TIME 



r^ 



,'* — ^ 



• ,o„ — ^ 1^ ^^ '~\ — ^ '~',  f"', — ^ f~\ — ^ r-\ 



J^ V/vJ^ \ . f^ 



^^^v^^W'-'V 



Figure 3. — ECG lead two and acceleration Beg in a California gray whale. Paper speed - 50 mm/ 

 sec. The Beg calibration of 3 cm/sec- is shown in the lower right. 



ECG-n '~';—.^ ';—'!' — ^/'~^(^~^,'-^^ — """f^' — "^ r~\'"~^ f'l^ f-\ '^r-^^«*- /,-^'^~~-^'' — '^r^''~~^r~^'' — ",'"'■ 



ULF Bcqo 



TIME 



^^AJ';U\wA^wvA^\^;'vvv';V^  ,^ , /. v^^v'^'"'^'-'^^ 



. J «v 



Figure 4. — The Beg with Gigi during one breath. Paper speed = 25 mm/sec. The respiratory 

 influence on the Beg is considerably greater in the whale than other species. This is probably due 

 to the necessarily rapid and large tidal exchange. 



MOUSE 



An 17.25. R I9h, 27.04g . 16.8.68 



,v— Av-v^/W-^^i^V^^ 



2cm 



-lO.lmV 



MAN 



ULF Be 



q„ A^v^/yA^~^YV-^YV-'Y^ ^ 



ECG-n- 



WHALE 



ECG-n 



ULF Bcg„ 



TIME 



-V^^ — \^^ — V-^ 



3cm 

 sec 2 



Figure 5. — The ultra low-frequency acceleration Bcg's in a 27-gm mouse (top record), a 73.000-gm 

 man (middle record), and a 4.S00.000-gm whale (lower record). The ECG s are also shown. Note 

 the more rapid paper speed in the mouse Beg. Considering the 167.000-fold difference m body 

 mass, as well as the differences in body shape, amount and distribution of fat. and instrumentation, 

 the records are remarkably similar. The mouse Beg is from Juznic. G., Bibl. Cardiol. 26:281-291. 1970. 

 The human Beg is courtesy of Dr. Aaron G. Dinaburg. 



different in the whale from other 

 mammals. Green (1971) describes the 

 course and relations thus: "Leaving the 

 left ventricle, the aorta makes the 

 characteristic left arch before passing 

 superficially and caudally to lie just 

 under the center of the thoracic 

 cavity to pass through the diaphragm." 



Body acceleration, which is closely 

 related to blood acceleration, is a 

 constant factor among various mam- 

 malian species. A peak-to-peak body 

 acceleration of 2.5-5 cm/sec- (about 

 2.5-5 millig) seems to be optimum. If 

 the acceleration is greater, as with 

 severe aortic insufficiency, the slight 

 motion now becomes quite noticeable. 

 If the whale's body acceleration were 

 proportionateK large in relation to its 

 mass, the motion could become un- 

 comfortable. Why a smaller normal 

 acceleration would not be feasible, or 

 indeed why an initial ventricular 

 impulse is necessary at all. is difficult 

 to guess. 



Other constants occur among 

 mammals. For example, with rare 

 exceptions such as the giraffe, arterial 

 blood pressure is very similar in differ- 

 ent species (Altman and Dittmer. 

 197 1. p. 405-4(18). One could spec- 

 ulate why these values are so appro- 

 priate. If normal arterial pressure were 

 higher, either the vessel walls would 

 have to be of considerably stiffcr 

 material, or the\ would have to be 

 so thick that the ratio of wall thick- 

 ness to lumen would be impractical. 

 If normal pressure were lower, perfu- 

 sion through the necessarily small 

 capillary vessels would be diflicult. 

 Perhaps even more pertinent a con- 

 stant involves the relative masses of 

 the heart and body in different mam- 

 mals (Table 1). Apparently there is 

 more variation within species than 

 among species. 



The general form o\ Gigis Beg is 

 very similar to that given for normal 

 man h\ .Scarborough et al. ( 1958). One 

 can certainly recognize an HIJ ci>m- 

 plex and an LMN complex. It seems 

 that greater differences in amplitude 

 and lorni are caused by faulty tech- 

 nique, such as a heavy bed and poor 



12 



