scholarly journals Coronary Microvascular Dysfunction in Takotsubo Syndrome Assessed by Angiography-Derived Index of Microcirculatory Resistance: A Pressure-Wire-Free Tool

2021 ◽  
Vol 10 (19) ◽  
pp. 4331
Author(s):  
Jordi Sans-Roselló ◽  
Estefanía Fernández-Peregrina ◽  
Albert Duran-Cambra ◽  
Jose Carreras-Mora ◽  
Alessandro Sionis ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin T ◽  
Systolic Dysfunction ◽  
Microvascular Dysfunction ◽  
Left Ventricular Ejection ◽  
Coronary Microvascular Dysfunction ◽  
Cardiac Troponin T ◽  
Takotsubo Syndrome ◽  
Pressure Wire ◽  
Index Of Microcirculatory Resistance

Background: Coronary microvascular dysfunction (CMD) has been proposed as a key mechanism in Takotsubo syndrome (TTS). The non-hyperaemic angiography-derived index of microcirculatory resistance (NH-IMRangio) has been validated as a pressure-wire-free tool for the assessment of coronary microvasculature. We aimed to study the presence of CMD in TTS patients and its association with levels of cardiac biomarkers and systolic dysfunction patterns. Methods: We recruited 181 consecutive patients admitted for TTS who underwent cardiac angiography at a tertiary center from January 2014 to January 2021. CMD was defined as an NH-IMRangio ≥ 25. Plasma levels of NT-proBNP, high-sensitive cardiac troponin T (hs-cTnT) and the left ventricular ejection fraction (LVEF) by echocardiography were measured at admission. Results: Mean age was 75.3 years, 83% were women and median LVEF was 45%. All patients presented CMD (NH-IMRangio ≥ 25) in at least one epicardial coronary artery. The left anterior descending artery (LAD) showed higher median NH-IMRangio values than left circumflex (LCx) and right coronary arteries (RCA) (44.6 vs. 31.3 vs. 36.1, respectively; p < 0.001). NH-IMRangio values differed among ventricular contractility patterns in the LAD and RCA (p = 0.0152 and 0.0189, respectively) with the highest values in the mid-ventricular + apical and mid-ventricular + basal patterns. NT-proBNP levels, but not high-sensitive cardiac troponin T (hs-cTnT), were correlated with both the degree and the extent of CMD in patients with TTS. Lower LVEF was also associated with higher NH-IMRangio values. Conclusions: CMD is highly prevalent in patients admitted for TTS and is associated with both a higher degree of systolic dysfunction and higher BNP levels, but not troponin.

Abstract 13428: Cardiac Troponin T Level is Associated With Myocardial Recovery in Fulminant Myocarditis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Toru Kondo ◽  
Naoki Shibata ◽  
shingo kazama ◽  
Yuki Kimura ◽  
Hideo Oishi ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin T ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Fulminant Myocarditis ◽  
Circulatory Support ◽  
Cardiac Troponin T ◽  
Myocardial Recovery ◽  
Ventricular Ejection Fraction ◽  
Va Ecmo

Background: Fulminant myocarditis (FM) is a fatal disease that causes rapid-onset severe heart failure requiring inotropes or mechanical circulatory support (MCS). Because insufficient myocardial recovery requires durable left ventricular assist device or heart transplantation, the course of myocardial recovery should be predicted. Hypothesis: Cardiac troponins, which elevates due to myocardial damage, may associate with myocardial recovery in FM. Purpose: We aimed to investigate the relationship between cardiac troponin T (TnT) levels and myocardial recovery course in patients with FM. Method: We performed a retrospective medical record review of 19 patients with FM requiring MCS from May 2012 to January 2020. The serial changes of one-week left ventricular ejection fraction (LVEF) after MCS implantation according to TnT levels were evaluated. Results: Median age was 50 years and 10 patients were male. As for initial MCS, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) with intra-aortic balloon pumping (IABP) were used in 13 patients, IABP in 4 patients, VA-ECMO in one patient, and impella 2.5 in one patient. Median peak TnT level within one week after MCS implantation were 4.43 (2.47 - 34.6) ng/mL. The patients were divided into High-TnT group and Low-TnT group according to median peak TnT level. All patients in both groups were alive until 7 days after MCS implantation, and LVEF on day 7 was significantly lower in the High-TnT group (Fig). TnT level was highest on day 1 and gradually decreased in the High-TnT group (Fig). Six patients died during hospitalization in the High-TnT group, in contrast, only one patient died in the Low-TnT group (p=0.020). Peak TnT level in patients with LVEF ≥30% (n=8) on day 7 was significantly lower than in patients with LVEF <30% (2.40 vs 13.5 ng/mL, p=0.012), however, other laboratory parameters showed no significant differences. Conclusion: Higher TnT level showed impaired myocardial recovery in patients with FM.

scholarly journals Dilated cardiomyopathy mutation (R174W) in troponin T attenuates the length-mediated increase in cross-bridge recruitment and myofilament Ca2+ sensitivity

2019 ◽  
Vol 317 (3) ◽  
pp. H648-H657
Author(s):  
Sherif M. Reda ◽  
Murali Chandra
Keyword(s):  
Guinea Pig ◽  
Dilated Cardiomyopathy ◽  
Cardiac Troponin ◽  
Troponin T ◽  
Heart Function ◽  
Systolic Dysfunction ◽  
Left Ventricular ◽  
Cardiac Troponin T ◽  
Cross Bridge ◽  
Length Dependent Activation

Alterations in length-dependent activation (LDA) may constitute a mechanism by which cardiomyopathy mutations lead to deleterious phenotypes and compromised heart function, because LDA underlies the molecular basis by which the heart tunes myocardial force production on a beat-to-beat basis (Frank-Starling mechanism). In this study, we investigated the effect of DCM-linked mutation (R173W) in human cardiac troponin T (TnT) on myofilament LDA. R173W mutation is associated with left ventricular dilatation and systolic dysfunction and is found in multiple families. R173W mutation is in the central region (residues 80–180) of TnT, which is known to be important for myofilament cooperativity and cross-bridge (XB) recruitment. Steady-state and dynamic contractile parameters were measured in detergent-skinned guinea pig left ventricular muscle fibers reconstituted with recombinant guinea pig wild-type TnT (TnTWT) or mutant TnT (TnTR174W; guinea pig analog of human R173W mutation) at two different sarcomere lengths (SL): short (1.9 µm) and long (2.3 µm). TnTR174W decreased pCa50 (−log [Ca2+]free required for half-maximal activation) to a greater extent at long than at short SL; for example, pCa50 decreased by 0.12 pCa units at long SL and by 0.06 pCa units at short SL. Differential changes in pCa50 at short and long SL attenuated the SL-dependent increase in myofilament Ca2+ sensitivity (ΔpCa50) in TnTR174W fibers; ΔpCa50 was 0.10 units in TnTWT fibers but only 0.04 units in TnTR174W fibers. Furthermore, TnTR174W blunted the SL-dependent increase in the magnitude of XB recruitment. Our observations suggest that the R173W mutation in human cardiac TnT may impair Frank-Starling mechanism. NEW & NOTEWORTHY This work characterizes the effect of dilated cardiomyopathy mutation in cardiac troponin T (TnTR174W) on myofilament length-dependent activation. TnTR174W attenuates the length-dependent increase in cross-bridge recruitment and myofilament Ca2+ sensitivity.

Expression of cardiac troponin T with COOH-terminal truncation accelerates cross-bridge interaction kinetics in mouse myocardium

2004 ◽  
Vol 287 (4) ◽  
pp. H1756-H1761 ◽  
Author(s):  
Julian E. Stelzer ◽  
Jitandrakumar R. Patel ◽  
M. Charlotte Olsson ◽  
Daniel P. Fitzsimons ◽  
Leslie A. Leinwand ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Thin Filament ◽  
Troponin T ◽  
Systolic Function ◽  
Systolic Dysfunction ◽  
Hill Coefficient ◽  
Cardiac Troponin T ◽  
Cross Bridge ◽  
Interaction Kinetics ◽  
Filament Activation

Transgenic mice expressing an allele of cardiac troponin T (cTnT) with a COOH-terminal truncation (cTnTtrunc) exhibit severe diastolic and mild systolic dysfunction. We tested the hypothesis that contractile dysfunction in myocardium expressing low levels of cTnTtrunc (i.e., <5%) is due to slowed cross-bridge kinetics and reduced thin filament activation as a consequence of reduced cross-bridge binding. We measured the Ca2+ sensitivity of force development [pCa for half-maximal tension generation (pCa50)] and the rate constant of force redevelopment ( ktr) in cTnTtrunc and wild-type (WT) skinned myocardium both in the absence and in the presence of a strong-binding, non-force-generating derivative of myosin subfragment-1 (NEM-S1). Compared with WT mice, cTnTtrunc mice exhibited greater pCa50, reduced steepness of the force-pCa relationship [Hill coefficient ( nH)], and faster ktr at submaximal Ca2+ concentration ([Ca2+]), i.e., reduced activation dependence of ktr. Treatment with NEM-S1 elicited similar increases in pCa50 and similar reductions in nH in WT and cTnTtrunc myocardium but elicited greater increases in ktr at submaximal activation in cTnTtrunc myocardium. Contrary to our initial hypothesis, cTnTtrunc appears to enhance thin filament activation in myocardium, which is manifested as significant increases in Ca2+-activated force and the rate of cross-bridge attachment at submaximal [Ca2+]. Although these mechanisms would not be expected to depress systolic function per se in cTnTtrunc hearts, they would account for slowed rates of myocardial relaxation during early diastole.

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