Morphological varieties of the Purkinje fiber network in mammalian hearts, as revealed by light and electron microscopy

Abstract

(group III) resembled ventricular cardiac myocytes in cytoarchitecture. Morphologically, whales and seals respectively belonged to Purkinje cells of group I and group II. These findings indicate that the structural variety of the Purkinje fiber network may reflect the conducting function and be related to the phylogeny of the mammalian species.

Transmural electrophysiological heterogeneity, the T-wave and ventricular arrhythmias

“…Purkinje fibers connect to the subendocardium in humans to form the origin of myocardial activation. Purkinje-muscle junctions (PMJs) are discrete sites where Purkinje fibers branch either directly to fibers of myocardial cells (Ono et al, 2009), or indirectly via a transitional compartment (Martinez-Palomo et al, 1970;Shimada et al, 1984;Tranum-Jensen et al, 1991). The discrete nature of the PMJ presents a resistive barrier for conduction whereby the success of impulse transmission is dependent upon the electrotonic loading conditions at the junctional site.…”

The infrahisian conduction system and endocavitary cardiac structures: relevance for the invasive electrophysiologist

“…1), and gradually diminishes such that a delicate insulating layer is seen to surround individual Purkinje fibers (Fig. 2) [14, 15]. The His-Purkinje system is specialized for rapid conduction, with conduction velocities of 2.3 m/s as compared to 0.75 m/s in ventricular muscle, which facilitates rapid activation and synchronous contraction of the ventricles [16].…”

“…The distribution is not uniform, for example with a predilection for the papillary muscles and sparse distribution over the base of the ventricles [20]. Purkinje fibers drape the ventricular cavity as free running fibers and penetrating the subendocardium to a degree which varies between species and in humans is reported to be approximately for a third of the myocardial thickness [14, 15, 30, 31]. There is also considerable variation between mammalian species in insulation (individual versus groups of cells), branching pattern, association with endocavitary structures, and cellular ultrastructure of Purkinje fibers [15].…”

Role of Indoxyl Sulfate as a Predisposing Factor for Atrial Fibrillation in Renal Dysfunction

“…After rinsing with cacodylate buffer, they were dehydrated through a graded series of ethanol solutions. Samples for scanning electron microscopy were dried by the tert‐butyl alcohol freezing method and mounted on aluminum stubs with carbon tapes and silver paste and then coated lightly with platinum 23, 24. Samples for transmission electron microscopy were embedded in epoxy resin and cut into ultrathin sections (80 to 90 nm) and stained with uranyl acetate and lead citrate.…”