<i>In vivo</i> characterization of rate-dependent impact on the QT interval of <i>microminipig</i> assessed by atrial electrical pacing: Development of correction formulae of QT interval

Abstract

Correction formulae of QT interval were developed for the halothane-anesthetized microminipigs by adopting atrial pacing (n=5), which were compared with Bazett's and Fridericia's formulae for humans, and Van de Water's one for dogs. The correction formulae: QTc=QT−0.2072(RR−750) as linear and QTc=QT/(RR/750) 0.4007 as non-linear equations, were developed for microminipigs. These formulae can better correct the QT interval of the microminipigs compared with each of the conventional ones for humans and dogs. Moreover, analysis of the slope constant α values indicates that the rate-dependent change in the ventricular repolarization period of microminipig may better mimic that of humans than that of dogs.

Characterization of the electrocardiogram of <i>microminipig</i> in comparison with that of Clawn miniature swine: impacts of miniaturization of body size on electrocardiographic indices

“…The QTc and JTc were calculated with Fridericia’s formula: QTc=QT/(RR/1,000) 1/3 and JTc=JT/(RR/1,000) 1/3 , respectively [ 1 ]. In our previous study using the QT/RR plot analysis of microminipig [ 4 ], Fridericia’s formula corrected the QT interval for the heart rate better than Van de Water’s or Bazett’s one. The same result has been reported for some miniature swine including Göttingen [ 8 ] and NIBS [ 6 ].…”