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Towards an integrated understanding of cardiac arrhythmogenesis − Growing roles of experimental pathology
Author(s) -
Tanaka Hideo,
Matsuyama Takaaki,
Takamatsu Tetsuro
Publication year - 2017
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/pin.12487
Subject(s) - gap junction , pathogenesis , electrical conduction system of the heart , atrial fibrillation , intercalated disc , myocyte , medicine , endocardium , fibrillation , electrophysiology , pathological , cardiology , neuroscience , intracellular , pathology , electrocardiography , biology , microbiology and biotechnology
Cardiac arrhythmias have long been regarded as derangement of electrical impulse initiation and conduction within the heart. However, underlying mechanisms for arrhythmogenesis are not fully understood solely from the electrophysiological viewpoint. This review article discusses pathogenesis of arrhythmias from non‐electrical aspects, which were elucidated by spatiotemporal imaging of functional molecules in combination with morphological analysis of living heart tissues. Intracellular Ca 2+ ([Ca 2+ ] i ) overload, caused by myocardial injury, provokes Ca 2+ waves that could lead to abnormal excitations, i.e., triggered arrhythmias. Depressed Ca 2+ release from the sarcoplasmic reticulum, caused by ischemia, heart failure, or T‐tubular remodeling, results in spatiotemporally inhomogeneous [Ca 2+ ] i dynamics that could disturb impulse conduction, leading to reentrant tachyarrhythmias. Impairment of the gap junction‐mediated intercellular communications, which provokes derangement of impulse propagation of the myocardium, also leads to reentrant arrhythmias. Interpositions of non‐cardiomyocytes, especially fibroblasts, in the myocardium could also contribute to arrhythmogenesis via heterocellular gap‐junctional coupling with cardiomyocytes. Furthermore, alterations in myocardial histology, e.g., density and arrangements of myocytes in association with gap‐junctional distributions, could constitute important pathologic bases of atrial fibrillation. Integration of these molecular, functional, and morphological features of the myocardium, unveiled by experimental pathological approaches, would pave a new way for understanding pathogenesis of cardiac arrhythmias.