Remodeling of Transverse Tubular System: A Major Factor Inducing Heart Failure in Myocarditis?

Abstract Background Over the last thirty years, there has been exponential growth in the number and scale of national cardiovascular disease registries. We aimed to provide a comprehensive outline of contemporary national cardiac registries across all subspecialties. Methods We performed a systematic literature review by searching OvidMedline in August 2019 to identify registries relating to six pre-specified domains (Table). For inclusion, registries had to be national in nature, actively collecting data, and publishing either peer-reviewed publications or online reports. Results A total of 24,076 records were identified from six domain-specific Medline searches; 24,057 abstracts were screened with 19,435 non-relevant records excluded; 4,624 full texts were screened with 4,473 non-relevant texts excluded; and 151 registries met inclusion criteria representing 51 countries. Of these, 15 related to cardiac surgery, 27 to arrhythmia (17 device, 5 ablation, 7 atrial fibrillation), 21 to congenital heart disease (14 general, 2 interventional, 4 surgical, and 1 disease specific), 43 to coronary disease or percutaneous coronary intervention (22 PCI, 21 CAD), 27 to heart failure (13 heart failure, 5 transplant, 2 mechanical support, 7 disease specific), and 18 related to structural intervention (3 any, 13 transcatheter aortic valve replacement, 2 mitral intervention). Nine national registries (USA, Sweden, Finland, Denmark, UK, Portugal, Norway, Taiwan, and Singapore) covered multiple domains. Quality scoring using the Monash University Clinical Quality Registry Grading System (a composite score of recruitment, and data completeness, definitions, reliability and validation), demonstrated marked heterogeneity in quality between registries. Conclusions Cardiac registries have seen rapid growth, however the use and quality among various subspecialties differs markedly across world regions. Given the multiple benefits, clinicians, funders and health bureaucrats should be encouraged to focus on the range, quality and uptake of national registries. Figure 1 Funding Acknowledgement Type of funding source: None

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A STUDY OF THE T SYSTEM IN RAT HEART

The Journal of Cell Biology ◽

10.1083/jcb.44.1.1 ◽

1970 ◽

Vol 44 (1) ◽

pp. 1-19 ◽

Cited By ~ 140

Author(s):

W. G. Forssmann ◽

L. Girardier

Keyword(s):

Rat Heart ◽

Photometric Method ◽

Ventricular Muscle ◽

Transverse Tubular System ◽

System A ◽

L System ◽

Line Region ◽

Specific Granules ◽

Sizable Proportion ◽

T System

The technique of extracellular space tracing with horseradish peroxidase is adapted for labeling the transverse tubular system (T system) in rat heart. In rat ventricular muscle the T system shows extensive branching and remarkable tortuosity. The T system can only be defined operationally, since it does not display specific morphological features throughout its entire structure. Owing to branching of the T system, a sizable proportion of the apposition between the T system and L system (or closed system) occurs at the level of longitudinal branches of the T system and is not restricted to the Z line region. The regions of apposition between the T system and L system are analyzed in rat ventricular muscle and skeletal muscle (diaphragm) and compared with the intercellular tight junctions (nexuses) of heart muscle by the use of a photometric method. The over-all thickness of the nexus is significantly smaller than that of T-L junctions in both cardiac and skeletal muscles. The thickness of the membranes of the T and L systems are not significantly different in the two muscles, but the gap between both membranes is larger in the heart. In atrial muscle the following two types of cells are found: (a) those cells with a well-developed T system in which the tubular diameter is quite uniform and the orientation predominantly longitudinal and, (b) cells with no T system, but with a well-developed L system. Atrial cells possessing a T system are richly provided with specific granules and show little micropinocytotic activity, whereas cells devoid of T system show intense micropinocytotic activity and few specific granules. The possible functional implications of these findings are discussed.

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