Monophasic action potential (MAP) can be recorded from the heart surface by optical method based on fluorescence measurement. The motion of isolated heart during experiment caused additional noise in recorded signal. The motion artifact can be eliminated by ratiometric fluorescence emission measurements. This study is based on experiments in which optical MAP measurement is done by single-wavelength and dualwavelength measurement of fluorescence emission. Both recording setups are presented and their advantages and disadvantages are discussed. MAPs recorded by both methods from isolated rabbit hearts perfused according to Langendorff are presented. Simultaneous electrograms (EG) and MAPs recording are analyzed and measurement of velocity of impulse conduction through heart tissue is presented., J. Kolářová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
An organ-preserving solution, including in its composition also organic molecules, prepared at the University of Wisconsin (UW), has been successfully used for preservation of liver, pancreas and kidney, and has recently been tested for long-term storage of isolated hearts. We have compared the effectiveness of the UW solution with that of a standard crystalloid cardioplegic solution (St. Thomas, ST) in the functional and structural preservation of isolated hearts. The hearts taken from 24 rabbits were mounted on a Langendorff preparation. After assessment of the left ventricular function by an intraventricular balloon, 40 ml of either cardioplegic solution were injected to arrest the hearts (12 UW and 12 ST), which were then immersed in the same solution for 4 h at 4 °C without perfusion. After this period, the hearts were normothermally reperfused with oxygenated Krebs-Henseleit solution for 30 min, and finally left ventricular function was assessed again. An electron microscopic evaluation was performed as well. Significantly higher recovery of left ventricular developed pressure (p<0.01) and of negative dP/dt (p<0.05), was observed after preservation with UW, while no difference on positive dP/dt was found. After reperfusion, left ventricular end-diastolic pressure significantly rose with ST (p<0.01), but did not change with UW; the difference between ST and UW was significant (p<0.01). Tissue water content was significantly lower in the hearts preserved with UW (p<0.05). Electron microscopic examination revealed generally good preservation with no substantial difference between the two solutions. We conclude that UW cardioplegic solution, rather than ST solution, associated with low temperature, provides better protection of isolated hearts against ischaemia and reperfusion injury after long-term preservation. This is probably due to the combined effects of antioxidants, cell- membrane impermeable substances and oncotic agents.