Relationship between action potential duration of ventricular cells and heart rate of rabbit under natural breathing

Abstract

The ECG and transmembrane action potentials of the ventricular cells of 40 albino rabbits at various heart rates under natural breathing were simultaneously recorded. After statistical analysis of the records of 126 units, quantitative relationships between action potential durations (APDs) and heart rates were found and regression equations were obtained by linear regression. In order to eliminate the effect of heart rates on APDs, the correction formulas on APDs were also worked out. After correction the effect of sinus cycle length (SCL) on APDs could be eliminated.

This study has provided a practical method for the study of the effect of different agents on the APDs of ventricular cells under more natural condition. Though the regression equations and correction formulas can only be applied in rabbits under natural breathing, this method might be adopted to work out the corresponding regression equations and correction formulas for other experimental animals. Therefore it has practical significance in a rather broad field.

Keywords

transmembrane action potentials / under natural breathing / sinus cycle length / action potential duration

References

[1] AshmanR, et al. . The effect of cyclelength changes upon the form and amplitude of the T deflection of the electrocardiogram. Am J Physiol, 1945, 143453-61

[2] EysterJAE, GilsonWE. The development and contour of cardiac injury potential. Am J Physiol, 1946, 145507-20

[3] HoffmanBF, SucklingEE. Effect of heart rate on cardiac membrane potentials and the unipolar electrogram. Am J Physiol, 1954, 179123-30

[4] TrautweinW, DudelJ. Aktionpotential und Mechanogramm des Warmblüterherzmuskels als Funktion der Schlagfrequenz. Pflügers Archiv, 1954, 26024-39

[5] GussSB, et al. . Human ventricular refractoriness, effects of cycle length, pacing site and atropine. Circulation, 1976, 53450-55

[6] AhnveS, VallinH. Influence of heart rate and inhibition of autonomic tone on the QT interval. Circulation, 1982, 65435-39

[7] BazettHC. An analysis of the time-relations of electrocardiograms. Heart, 1920, 753-53

[8] ShaoruLi, et al. . Simultaneous receording of ECG and transmembrane action potentials of venticular cells of anesthetized rabbit under natural breathing. Acta Acad Med Wuhan, 1984, 4(1): 21-22

[9] MilneJR, et al. . Effect of intravenous propranolol on QT interval: A new method of assessment. Br Heart J, 1980, 431-1