Papillary MusclesMusclesMuscle ProteinsMuscle, SkeletalMyocardial ContractionMuscle, SmoothMuscle Fibers, SkeletalMyocardiumHeartMuscle ContractionMuscle, Smooth, VascularMuscle DevelopmentMyocytes, CardiacMuscle Fibers, Fast-TwitchGuinea PigsChordae TendineaeHeart VentriclesMuscle FatigueMuscle Fibers, Slow-TwitchCalciumMuscle DenervationMyofibrilsMitochondria, MuscleMitral Valve InsufficiencyMyocytes, Smooth MuscleRabbitsIsometric ContractionMuscle RelaxationAction PotentialsFerretsMitral ValveNeck MusclesOculomotor MusclesSarcomeresTime FactorsMuscle, StriatedMuscle CellsMuscle SpindlesElectric StimulationRespiratory MusclesMuscle WeaknessCardiac OutputDogsCardiac Surgical ProceduresCardiomyopathiesArrhythmias, CardiacAbdominal MusclesIsoproterenolQuadriceps MuscleVentricular FunctionSarcoplasmic ReticulumCardiomegalySarcolemmaMyosin Heavy ChainsRats, WistarCells, CulturedCatsMembrane PotentialsMasseter MuscleAequorinRats, Sprague-DawleyFacial MusclesMasticatory MusclesIntercostal MusclesPurkinje FibersMuscular DiseasesElectromyographyBiomechanical PhenomenaTroponin CTroponin IMuscular AtrophyElectrophysiologyHeart Conduction SystemTroponinRyanodineCardiac MyosinsSatellite Cells, Skeletal MuscleHeart Rupture, Post-InfarctionDepression, ChemicalHeart RatePectoralis MusclesEchocardiographyDose-Response Relationship, DrugCardiotonic AgentsRNA, MessengerDeath, Sudden, CardiacKineticsCineradiographyActinsHeart RuptureEndocardiumDystrophinTropomyosinRyanodine Receptor Calcium Release ChannelModels, CardiovascularCardiac Pacing, ArtificialElectrocardiographyPsoas MusclesHeart AtriaCaffeine