Estimation of cardiac output and stroke volume from thermal equilibration and heartbeat rates in fish

✍ Scribed by William W. Reynolds; Martha E. Casterlin

• Book ID: 104614870
• Publisher: Springer
• Year: 1978
• Tongue: English
• Weight: 286 KB
• Volume: 57
• Category: Article
• ISSN: 1573-5141
• DOI: 10.1007/bf00018625

✦ Synopsis

Cardiac output and stroke volume were estimated for a 200 g largemouth blackbass (Micropterus salmoides) by a modified whole-body thermodilution method using the relation between thermal equilibration rates and heartbeat frequencies . The reciprocal of the thermal time constant, k (min'), was related to the heartbeat frequency, F (beats min -'), by the equation k=0.00146 F + 0 .309 ; the slope is the weight-specific stroke volume (ml g -') and the intercept is the weight-specific heat transfer constant (cal 'C-'min-'g-) . Stroke volume was 0 .292 ml (0.00146 ml/g body weight), yielding cardiac output values ranging from 44 ml kg ' min -' (at 3o beats min -) to 158 ml kg ' min -' (at io8 beats min -'), or 4.4 to 15 .8% of body weight. Active (convective) heat transfer due to blood flow constituted an estimated 11 to 34% (mean 22.5%) of total heat transfer, depending on heartbeat frequency ; this variability constitutes physiological thermoregulation .