In control cardiomyocytes, increasing rate of pacing from 0.5 to 2 Hz resulted in a positive cell shortening-frequency response, which was inverted in cardiomyocytes isolated from LPS-treated rats.
In the current study, we apply a computational model derived from force velocity relationships to explore how sustained power output is systematically affected by shortening velocity, operational frequency, and strain amplitude.
69 As the health care system transforms into a payer system guided towards bundle reimbursements, the health care provider will need to remain cognizant of lowering hospitalization frequency and shortening length of stay.
Without Zn2+ exposure, cardiomyocyte peak shortening and maximum shortening velocity were statistically enhanced in HG compared to nonHG at 2 and 4 Hz pacing frequency, but not at 6 Hz.
There were also significant 'HG×freq' interactions for peak shortening and maximum shortening velocity (P<0.01 in Table 4) suggesting that the HG group was more susceptible to the reduction in contractile function with increasing pacing frequency.
The obvious difference between the two treatment frequencies appears to be shortening of morbidity time by intensive GMA.
Functionally, DM had systolic dysfunction characterized by decreased endocardial fractional shortening and posterior wall shortening velocity.
Fractional shortening and posterior wall shortening velocity were lower in DM than C and DM-R.
However, the increase in overall dynamics in mut-p53 cells is only part of the picture, as in these cells the shortening rate was significantly decreased and the rescue frequency per length shortened was increased.
Ethanol exposure depressed cardiomyocyte contractile function including decreased cell shortening amplitude and maximal velocity of shortening/relengthening as well as prolonged relengthening duration and a greater decline in peak shortening in response to increasing stimulus frequency, the effect of which was significantly exaggerated by ALDH2 KO.
Considering the effects of all the various activity patterns published there is no positive evidence that shortening velocity or MyHC composition is dependent on instantaneous frequency, and the amount of stimulation seems to be the important factor (Gundersen, 1998).
