DogsHeartCross CirculationHeart RateMyocardial ContractionMyocardiumHeart FailureCardiac Pacing, ArtificialVentricular FunctionVoltage-Sensitive Dye ImagingDog DiseasesPericardiumCoronary CirculationEndocardiumHeart Conduction SystemModels, CardiovascularHemodynamicsHeart VentriclesSinoatrial NodeHeart AtriaHeart DiseasesHeart BlockVentricular Function, LeftVentricular PressureMyocardial IschemiaHeart TransplantationHeart Defects, CongenitalPerfusionMyocardial InfarctionElectrocardiographyMyocardial Reperfusion InjurySystolePurkinje FibersVentricular FibrillationTime FactorsDistemper Virus, CanineTachycardiaCardiac VolumeAtrioventricular NodeAtrial Function5'-NucleotidaseCoronary DiseaseFetal HeartElectrophysiologic Techniques, CardiacSarcolemmaCardiotonic AgentsCoronary VesselsMyocytes, CardiacOxygen ConsumptionAction PotentialsHalothaneParvovirus, CanineStroke VolumeAnti-Arrhythmia AgentsHeart ValvesDisease Models, AnimalVentricular Function, RightRefractory Period, ElectrophysiologicalDisopyramideEnfluraneArrhythmias, CardiacMyocardial ReperfusionCalcium ChloridePapillary MusclesTachycardia, VentricularCuspidElectrophysiologyPotassium Channels