Papillary MusclesChordae TendineaeMitral Valve InsufficiencyMitral ValveNecrosisMusclesMyocardiumMyocardial ContractionTechnetium Tc 99m PyrophosphateMuscle ProteinsMuscle, SmoothHeartMuscle, SkeletalMuscle ContractionMuscle Fibers, SkeletalCardiomyopathiesMuscle, Smooth, VascularMyocardial InfarctionGuinea PigsMuscle DevelopmentCreatine Kinase, MB FormTroponin IHeart VentriclesFerretsCreatine KinaseElectric InjuriesTumor Necrosis Factor-alphaMyocarditisTroponin TIsoproterenolTime FactorsAction PotentialsDogsHeart InjuriesMyocardial IschemiaRabbitsMuscle FatigueMuscle Fibers, Fast-TwitchMuscle DenervationIsometric ContractionMuscle Fibers, Slow-TwitchCardiotonic AgentsMyocardial Reperfusion InjuryAequorinElectrocardiographyHeart Rupture, Post-InfarctionCalciumMyocytes, Smooth MuscleMuscle RelaxationMitochondria, MuscleElectric StimulationCineradiographyNeck MusclesOculomotor MusclesHeart RuptureMyocardial ReperfusionEchocardiographyCatsMuscle, StriatedDepression, ChemicalMuscle SpindlesBiological MarkersCoronary VesselsPurkinje FibersMuscle WeaknessRespiratory MusclesVentricular Function, LeftHemodynamicsVentricular FunctionMitral Valve AnnuloplastyMyofibrilsCoronary CirculationMembrane PotentialsBiomechanical PhenomenaRats, WistarAbdominal MusclesEndocardiumElectrophysiologyQuadriceps MuscleDisease Models, AnimalMuscle CellsMagnetic Resonance ImagingCross CirculationMasseter MuscleArrhythmias, CardiacMasticatory MusclesFacial MusclesAnti-Arrhythmia AgentsStimulation, ChemicalDose-Response Relationship, DrugHeart RateElectromyographyTroponinIntercostal Muscles