New model of ventricular fibrillation.
The purpose of this study was to develop a more efficient and stable model of ventricular fibrillation (VF) in the isolated rabbit heart, because there is not a satisfactory model with this animal. We also observed the effects of increasing extracellular calcium in the stability and reversibility of the arrhythmia. After suspending the hearts in a classical Langendorff preparation, VF was induced by burst stimulation (current = 2.0 mA, pulse duration = 3 milliseconds, frequency = 50 Hz, voltage = 10 V, duration of stimulation = 5 minutes). The hearts were then divided into 2 groups, A and B. The hearts in group B were perfused with a modified Krebs-Henseleit solution, which contained twice as much calcium as the solution used in the other group. The rate of success with this model was 100% for both groups. The hearts fibrillated up to 30 minutes in group A and more than 40 minutes in group B, longer then all studies ever published in rabbit hearts. Ventricular fibrillation reverted to sinus rhythm in 100% of the hearts of group A when treated with an antifibrillatory drug, whereas no reversion at all was observed in the hearts of group B. We conclude that high extracellular calcium makes the reversion to sinus rhythm more difficult in this model. Our high rate of success and the exceptionally stable and long-lasting VF turn our model very effective for the study of antiarrhythmic interventions in the isolated rabbit heart.
Emergency Department Research Laboratory, University of São Paulo School of Medicine, CEP: 05403-010 São Paulo, Brazil. andreferrari@mensa.org.br
André Ferrari
AF
de França Camargo
Anezka Carvalho Rubin
AC
de Celis
Irineu Tadeu
IT
Velasco
Vera
V
Pontieri
Augusto Scalabrini
AS
Neto
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D002118:Calcium / Q000008:administration & dosage; D004195:Disease Models, Animal; D004558:Electric Stimulation; D005947:Glucose / Q000008:administration & dosage; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D019188:Organ Preservation Solutions / Q000008:administration & dosage; D010477:Perfusion; D011817:Rabbits; D013997:Time Factors; D014325:Tromethamine / Q000008:administration & dosage; D014693:Ventricular Fibrillation / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; C074097:Krebs-Henseleit solution; D019188:Organ Preservation Solutions; D014325:Tromethamine; D005947:Glucose; D002118:Calcium