Electrocardiogram of the humpback whale (Megaptera noaeangliae) with specific reference to atrioventricular transmission and ventricular excitation

Meijler, F.L.; Wittkampf, Fred H.M.; Brennen, Kenneth R.; Baker, Verne; Wassenaar, C; Bakken, Earl E.

doi:10.1016/0735-1097(92)90120-c

Cited by 34 publications

(27 citation statements)

References 15 publications

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“…31 3. The conduction velocity, v x (xϭc, cell; a, atria; av, AV node; and hp, His-Purkinje), at each component of the path is preserved across species 10,21 in such a way that conduction velocity, v a , in the mouse atrium, for example, is close to that in the human atrium.…”

Section: Model Predictionmentioning

confidence: 99%

“…If one also includes the humpback whale, whose body weight is Ϸ30 000 kg and heart weight is Ϸ180 000g, the change occurs over 6 orders of magnitude. Yet, from mouse to whale, PR interval changes only from 40 to 400 ms. 8 Similarly, HR changes from 600 bpm in the conscious mouse 25 to Ϸ30 bpm in the humpback whale, 21 and West et al 2 have already found that HRϰBM Ϫ1/4 . In Figure 2, we have plotted ln(PR) versus ln(BM), whose best linear fit is yϭ3.98ϩ0.24x.…”

Section: Scaling Of Pr Interval and Hrmentioning

confidence: 99%

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The collected data fall into 4 different categories based on the mode in which they were reported in the literature for each of the 3 parameters (ie, PR, HR, and BM): (1) measurements from single animals, (2) multiple animal measurements reported as mean values without SD, (3) multiple animal measurements reported as means with SDs, and (4) values reported as ranges without means or SDs. For convenience, the allometric equation YϭY 0 · BM b can be transformed into a logarithmic form, lnYϭlnY 0 ϩb · lnBM, which describes a straight line of the form yϭinterceptϩbx.…”

Section: Data Collection and Analysismentioning

confidence: 99%

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From Mouse to Whale

et al. 2004

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Background-On the ECG, the PR interval measures the time taken by an electrical impulse generated in the sinoatrial node to propagate from atria to ventricles. From mouse to whale, the PR interval increases Ϸ10 1 , whereas body mass (BM) augments Ϸ10 6 . Scaling of many biological processes (eg, metabolic rate, life span, aortic diameter) is described by the allometric equation YϭY 0 · BM b , where Y is the biological process and b is the scaling exponent that is an integer multiple of 1/4. Hierarchical branching networks have been proposed to be the underlying mechanism for the 1/4 power allometric law. Methods and Results-We first derived analytically the allometric equation for the PR interval. We assumed that the heart behaves as a set of "fractal-like" networks that tend to minimize propagation time across the conducting system while ensuring a hemodynamically optimal atrioventricular activation sequence. Our derivation yielded the relationship PRϰBM 1/4 . We subsequently obtained previously published values of PR interval, heart rate, and BM of 541 mammals representing 33 species. Double-logarithmic analysis demonstrates that PR interval increases as heart rate decreases, and both variables relate to BM following the 1/4 power law. Most important, the best fit for PR versus BM is described by the equation PRϭ53

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Section: Model Predictionmentioning

confidence: 99%

Section: Scaling Of Pr Interval and Hrmentioning

confidence: 99%

Section: Data Collection and Analysismentioning

confidence: 99%

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From Mouse to Whale

et al. 2004

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“…The actual data justifying this fit have been reported previously. 4,5,7,[20][21][22] This formula, which describes the data shown in Figure 3, implies that at a theoretical heart length of zero, PR interval does not equal zero. It also describes the S-shape of the curve of the relationship between PR interval and heart length, This curve presents a possible difference between scaling of A V transmission time and other forms of scaling (allometric) of (cardiac) functions in mammais.…”

Section: Pr Time Versus Heart Lengthmentioning

confidence: 99%

“…4 Because considerably more small mammals were studied than large animais, there is a cluster of data points at the lower end of the curve and only a few data points at the higher end. It is interesting to note that at an extrapolated (nonexistent) heart si ze of zero there still would be a sizable PR interval.…”

Section: Mice Versus Rats Versus Horses Versus Whalementioning

confidence: 99%

Scaling of Atrioventricular Transmission in Mammalian Species: An Evolutionary Riddle!

Meijler

Strackee

Stokhof

et al. 2002

Cardiovasc electrophysiol

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Sealing of A V Transmission. "Sealing deals with the structural and funetional eonsequenees of changes in size or seale among otherwise similar organisms." It plays a key role in all studies on eomparative mammalian physiology and morphology. Heart weight is proportionally related to body weight and ean be described by a straightforward, so-ealled allometrie equation. We studied sealing of A V transmission times (PR intervals on the ECG) in 375 mammals of different dimensions and species. Sealing of A V transmission times versus heart length (third root of weight) is statistieally best described by a S-shaped curve. This implies that A V transmission time in mammals is not Iinearly related to heart length and does not depend solely on the length of the A V transmission system. The A V node fine-tunes A V transmission times at rest and during exercise in individuals; it proteets the ventricles against high-rate atrial arrhythmias sueh as atrial fibrillation; and it regulates basal A V transmission times in mammalian species of varying sizes. We eall the "how" and "why" of the sealing of A V transmission time in mammals an evolutionary riddle that deserves further study.

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Anatomy of the sinus node, av node, and his bundle of the heart of the sperm whale (Physeter macrocephalus), with a note on the absence of an os cordis

et al. 1995

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Given our morphological findings, we believe that the whale's comparatively short AV conduction time may be best explained by the sinus node and AV node functioning as coupled relaxation oscillators. Absence of an os cordis or central fibrous body or strong attachment between the two ventricles may pose both electrophysiological and hemodynamic hazards when the whale is no longer in its normally buoyant aquatic environment.

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Electrocardiogram of the humpback whale (Megaptera noaeangliae) with specific reference to atrioventricular transmission and ventricular excitation

Abstract: The results of the study may be of value for the understanding of the ECG in humans.

Cited by 34 publications

References 15 publications

From Mouse to Whale

From Mouse to Whale

Scaling of Atrioventricular Transmission in Mammalian Species: An Evolutionary Riddle!

Anatomy of the sinus node, av node, and his bundle of the heart of the sperm whale (Physeter macrocephalus), with a note on the absence of an os cordis

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