Assessment of Left Ventricular Muscle Mass with 201Thallium Myocardial Imaging

1981 ◽  
pp. 345-356 ◽  
Author(s):  
U. Büll ◽  
B. E. Strauer
Keyword(s):  
Muscle Mass ◽  
Left Ventricular ◽  
Myocardial Imaging ◽  
Ventricular Muscle ◽  
Left Ventricular Muscle Mass

scholarly journals Left ventricular muscle mass and diastolic function in patients with essential hypertension under long-term clonidine monotherapy

1991 ◽  
Vol 14 (2) ◽  
pp. 134-140 ◽  
Author(s):  
Jürgen Hüting ◽  
Veselin Mitrovic ◽  
Jochen Thormann ◽  
Hassan Bahavar ◽  
Martin Schlepper
Keyword(s):  
Essential Hypertension ◽  
Diastolic Function ◽  
Muscle Mass ◽  
Left Ventricular ◽  
Ventricular Muscle ◽  
Left Ventricular Muscle Mass

scholarly journals Titin isoform switching is a major cardiac adaptive response in hibernating grizzly bears

2008 ◽  
Vol 295 (1) ◽  
pp. H366-H371 ◽  
Author(s):  
O. Lynne Nelson ◽  
Charles T. Robbins ◽  
Yiming Wu ◽  
Henk Granzier
Keyword(s):  
Muscle Mass ◽  
Adaptive Response ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Grizzly Bears ◽  
Type I ◽  
Ventricular Muscle ◽  
Heart Rates ◽  
Cardiac Titin ◽  
Left Ventricular Muscle Mass

The hibernation phenomenon captures biological as well as clinical interests to understand how organs adapt. Here we studied how hibernating grizzly bears ( Ursus arctos horribilis) tolerate extremely low heart rates without developing cardiac chamber dilation. We evaluated cardiac filling function in unanesthetized grizzly bears by echocardiography during the active and hibernating period. Because both collagen and titin are involved in altering diastolic function, we investigated both in the myocardium of active and hibernating grizzly bears. Heart rates were reduced from 84 beats/min in active bears to 19 beats/min in hibernating bears. Diastolic volume, stroke volume, and left ventricular ejection fraction were not different. However, left ventricular muscle mass was significantly lower (300 ± 12 compared with 402 ± 14 g; P = 0.003) in the hibernating bears, and as a result the diastolic volume-to-left ventricular muscle mass ratio was significantly greater. Early ventricular filling deceleration times (106.4 ± 14 compared with 143.2 ± 20 ms; P = 0.002) were shorter during hibernation, suggesting increased ventricular stiffness. Restrictive pulmonary venous flow patterns supported this conclusion. Collagen type I and III comparisons did not reveal differences between the two groups of bears. In contrast, the expression of titin was altered by a significant upregulation of the stiffer N2B isoform at the expense of the more compliant N2BA isoform. The mean ratio of N2BA to N2B titin was 0.73 ± 0.07 in the active bears and decreased to 0.42 ± 0.03 ( P = 0.006) in the hibernating bears. The upregulation of stiff N2B cardiac titin is a likely explanation for the increased ventricular stiffness that was revealed by echocardiography, and we propose that it plays a role in preventing chamber dilation in hibernating grizzly bears. Thus our work identified changes in the alternative splicing of cardiac titin as a major adaptive response in hibernating grizzly bears.

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