Cardiomyocytes from terminally failing hearts display significant abnormalities in e-c-coupling, contractility and intracellular @entity141 handling. This study is the first to demonstrate the influence of end-stage @entity712 on specific properties of @entity141 sparks in @entity1 ventricular cardiomyocytes. We investigated the frequency and characteristics of spontaneously arising @entity141 sparks in single isolated @entity1 myocytes from terminally failing (HF) and non-failing (NF) control myocardium by using the @entity141 indicator @entity3576 . The @entity141 sparks were recorded by line-scan images along the longitudinal axis of the myocytes at a frequency of 250Hz. After loading the sarcoplasmic reticulum (SR) with @entity141 by repetitive field stimulation (10 pulses at 1Hz) the frequency of the @entity141 sparks immediately after stimulation (t = 0s) was reduced significantly in HF compared to NF (4.15 +/- 0.42 for NF vs. 2.81 +/- 0.20 for HF sparks s(-1), P = 0.05). This difference was present constantly in line-scan recordings up to 15s duration (t = 15s: 2.75 +/- 0.65 for NF vs. 1.36 +/- 0.34 for HF sparks s(-1), P = 0.05). The relative amplitude (F/F(0)) of @entity141 sparks was also significantly lower in HF cardiomyocytes (1.33 +/- 0.015 NF vs. 1.19 +/- 0.003 HF, t = 0s) and during subsequent recordings of 15s. Significant differences between HF and NF were also present in calculations of specific spark properties. The time to peak was estimated at 25.75 +/-0.88ms in HF and 18.68 +/- 0.45ms in NF cardiomyocytes (P = 0.05). Half-time of decay was 66.48 +/- 1.89ms (HF) vs. 44.15 +/- 1.65ms (NF, P < 0.05), and the @entity27915 ( @entity27915 ) was 3.99 +/- 0.06 microm (HF) vs. 3.5 +/- 0.07 microm (NF, P < 0.05). These data support the hypothesis that even in the absence of @entity299 , @entity141 sparks from @entity1 cardiomyocytes differ from previous results of animal studies with respect to the time-to-peak, half-time of decay and @entity27915 . The role of elevated external @entity141 in HF was studied by recording @entity141 sparks in HF cardiomyocytes with 10mmol external @entity141 concentration. Under these conditions, the average spark amplitude was increased from 1.19 +/- 0.003 (F/F(0), 2mmol @entity141 ) to 1.26 +/- 0.01 (F/F(0), 10mmol @entity141 ). We conclude that @entity1 @entity712 causes distinct changes in @entity141 spark frequency and characteristics comparable to results established in animal models of @entity712 . A reduced @entity141 load of the SR alone is unlikely to account for the observed differences between HF and NF and additional alterations in intracellular @entity141 release mechanisms must be postulated.

Calcium sparks in @entity1 ventricular cardiomyocytes from XXXX with @entity712 .

@entity1 :: ('9606', 'Species') :: ['human'] @entity712 :: ('MESH:D006333', 'Disease') :: ['heart failure'] @entity27915 :: ('MESH:C537270', 'Disease') :: ['full width at half-maximum', 'FWHM'] @entity3576 :: ('MESH:C059715', 'Chemical') :: ['Fluo-3'] @entity299 :: ('MESH:D006331', 'Disease') :: ['cardiac disease'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca(2+)']
@entity1 :: (9606,Species) :: ['patients']
