Strain, Strain Rate, and the Force Frequency Relationship in Patients with and without Heart Failure

2012 ◽  
Vol 25 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Susanna Mak ◽  
Harriette G.C. Van Spall ◽  
Rodrigo V. Wainstein ◽  
Zion Sasson
Keyword(s):  
Heart Failure ◽  
Strain Rate ◽  
Force Frequency ◽  
Frequency Relationship

Strain Rate in Children and Young Piglets Mirrors Changes in Contractility and Demonstrates a Force-Frequency Relationship

2017 ◽  
Vol 30 (8) ◽  
pp. 797-806 ◽  
Author(s):  
Silvia V. Alvarez ◽  
Etienne Fortin-Pellerin ◽  
Mohammed Alhabdan ◽  
Jesus S. Lomelin ◽  
Michal Kantoch ◽  
...  
Keyword(s):  
Strain Rate ◽  
Force Frequency ◽  
Frequency Relationship

Diaphragmatic free radical generation increases in an animal model of heart failure

2005 ◽  
Vol 99 (3) ◽  
pp. 1078-1084 ◽  
Author(s):  
Gerald S. Supinski ◽  
Leigh A. Callahan
Keyword(s):  
Heart Failure ◽  
Free Radicals ◽  
Free Radical ◽  
Protein Carbonyl ◽  
Protein Carbonyls ◽  
Force Frequency ◽  
Free Radical Generation ◽  
Coronary Ligation ◽  
Radical Generation ◽  
Frequency Relationship

Heart failure evokes diaphragm weakness, but the mechanism(s) by which this occurs are not known. We postulated that heart failure increases diaphragm free radical generation and that free radicals trigger diaphragm dysfunction in this condition. The purpose of the present study was to test this hypothesis. Experiments were performed using halothane-anesthetized sham-operated control rats and rats in which myocardial infarction was induced by ligation of the left anterior descending coronary artery. Animals were killed 6 wk after surgery, the diaphragms were removed, and the following were assessed: 1) mitochondrial hydrogen peroxide (H2O2) generation, 2) free radical generation in resting and contracting intact diaphragm using a fluorescent-indicator technique, 3) 8-isoprostane and protein carbonyls (indexes of free radical-induced lipid and protein oxidation), and 4) the diaphragm force-frequency relationship. In additional experiments, a group of coronary ligation animals were treated with polyethylene glycol-superoxide dismutase (PEG-SOD, 2,000 units·kg−1·day−1) for 4 wk. We found that coronary ligation evoked an increase in free radical formation by the intact diaphragm, increased diaphragm mitochondrial H2O2 generation, increased diaphragm protein carbonyl levels, and increased diaphragm 8-isoprostane levels compared with controls ( P < 0.001 for the first 3 comparisons, P < 0.05 for 8-isoprostane levels). Force generated in response to 20-Hz stimulation was reduced by coronary ligation ( P < 0.05); PEG-SOD administration restored force to control levels ( P < 0.03). These findings indicate that cardiac dysfunction due to coronary ligation increases diaphragm free radical generation and that free radicals evoke reductions in diaphragm force generation.

Force-frequency relationship in patients with chronic heart failure

1999 ◽  
Vol 5 (3) ◽  
pp. 80
Author(s):  
Makoto Kodama ◽  
Kiminori Kato ◽  
Satoru Hirono ◽  
Masahiro Ito ◽  
Koichi Fuse ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Force Frequency ◽  
Frequency Relationship

The force-frequency relationship and heart failure

1999 ◽  
Vol 8 (6) ◽  
pp. 11-13
Author(s):  
Tariq Salam ◽  
Martin M LeWinter
Keyword(s):  
Heart Failure ◽  
Force Frequency ◽  
Frequency Relationship

scholarly journals Effects of increased preload on the force-frequency response and contractile kinetics in early stages of cardiac muscle hypertrophy

2012 ◽  
Vol 302 (12) ◽  
pp. H2509-H2517 ◽  
Author(s):  
Kaylan M. Haizlip ◽  
Tepmanas Bupha-Intr ◽  
Brandon J. Biesiadecki ◽  
Paul M. L. Janssen
Keyword(s):  
Heart Failure ◽  
Frequency Response ◽  
White Male ◽  
Compensatory Hypertrophy ◽  
Force Frequency ◽  
Right Ventricular Free Wall ◽  
Early Stages ◽  
Force Frequency Response ◽  
Frequency Relationship ◽  
The Impact

Numerous studies have aimed to elucidate markers for the onset of decompensatory hypertrophy and heart failure in vivo and in vitro. Alterations in the force-frequency relationship are commonly used as markers for heart failure with a negative staircase being a hallmark of decompensated cardiac function. Here we aim to determine the functional and molecular alterations in the very early stages of compensatory hypertrophy through analysis of the force-frequency relationship, using a novel isolated muscle culture system that allows assessment of force-frequency relationship during the development of hypertrophy. New Zealand white male rabbit trabeculae excised from the right ventricular free wall were utilized for all experiments. Briefly, muscles held at constant preload and contracting isometrically were stimulated to contract in culture for 24 h, and in a subset up to 48 h. We found that, upon an increase in the preload and maintaining the muscles in culture for up to 24 h, there was an increase in baseline force produced by isolated trabeculae over time. This suggests a gradual compensatory response to the impact of increased preload. Temporal analysis of the force-frequency response during this progression revealed a significant blunting (at 12 h) and then reversal of the positive staircase as culture time increased (at 24 h). Phosphorylation analysis revealed a significant decrease in desmin and troponin (Tn)I phosphorylation from 12 to 24 h in culture. These results show that even very early on in the compensatory hypertrophy state, the force-frequency relationship is already affected. This effect on force-frequency relationship may, in addition to protein expression changes, be partially attributed to the alterations in myofilament protein phosphorylation.

scholarly journals Rate-Response Programming Tailored to the Force-Frequency Relationship Improves Exercise Tolerance in Chronic Heart Failure

2018 ◽  
Vol 6 (2) ◽  
pp. 105-113 ◽  
Author(s):  
John Gierula ◽  
Maria F. Paton ◽  
Judith E. Lowry ◽  
Haqeel A. Jamil ◽  
Rowenna Byrom ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Exercise Tolerance ◽  
Force Frequency ◽  
Frequency Relationship ◽  
Response Programming
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