Table 1.

Cardiac interval measurements in stage 46 Xenopus laevis determined by video analysis and intrathoracic extracellular cardiac recordings

	Video	ICR
n	53	6
AA interval	473±10	464±19 (ns)
VV interval	473±10	465±22 (ns)
AV interval	169±5	174±14 (ns)
A duration	105±3	na
V duration	148±4	na

Values are means ± SE. Video, video analysis; ICR, intrathoracic extracellular cardiac recordings; AA interval, the atrial cycle length; VV interval, the ventricular cycle length; AV interval, delay between onset of atrial and ventricular events; A duration, duration of the atrial contraction by video; V duration, duration of the ventricular contraction by video; ns, no significant difference between the two techniques by unpaired t-test evaluation; na, not applicable