A novel isolated dual perfusion/superfusion heart model for physiological and pharmacological evaluation of mammalian heart preparations
Introduction: Isolated perfused heart models such as perfusion and superfusion are commonly used for mammalian heart research. However, there are several fundamental limitations in the current techniques. In perfusion model, a suitable cannula is connected to the aorta and the perfusion is retrogradely performed. But, electrode displacement is a potential unwanted event resulted from heart contractions. In superfusion model, atrioventricular node (AV) node area is completely visible and fixed in the tissue bath after appropriate preparation, but tissue ischemia is inevitable due to the absence of cell to cell nutrition. The aim of the present study was to create a novel isolated dual perfusion/superfusion model to be used in heart physiological and pharmacological studies. Methods: The rabbit hearts (n=10) were excised. After preparation of proper sections, the electrodes were attached till the steady state appeared. The stimulation protocols consisting Wenckebach and recovery were then carried out during the isolated dual perfusion/superfusion as well as perfusion and superfusion models. Results: The AV node conduction time was increased from 33±4 ms in the isolated dual perfusion/superfusion heart model to 43±5 and 52±5 ms in perfusion and superfusion models, respectively (P<0.05). In addition, Wenckebach cycle length, effective and functional refractory periods were increased in perfusion and superfusion models compared to the isolated dual perfusion/superfusion model (P<0.05). Conclusion: This study shows the superiority of the isolated dual perfusion/superfusion heart model in tissue nutrition compared to the other common methods of mammalian heart studies.