Physiologic indices that reflect intracellular @entity141 cycling were chosen to evaluate contraction and relaxation properties of the univentricular heart. We hypothesized that these indices would be impaired in univentricular hearts. With @entity1442 , an increasing number of @entity1 are surviving with univentricular hearts supporting the systemic circulation. Similar to the adult failing heart, single ventricles may also manifest impaired @entity141 cycling, which may have important therapeutic implications. In our study, we did not actually measure @entity141 uptake or transients in the cardiac myocyte. Rather, we used previously validated physiologic indices that are known to reflect @entity141 cycling. Sixteen @entity1 were studied, eight with single ventricles (SV) and eight as matched control subjects. Systolic properties were studied using maximal derivative of ventricular pressure (dP/dtmax), force-frequency relationship, and mechanical restitution. Diastolic properties were assessed using time constant of relaxation (tau) and the relaxation-frequency relationship. The critical HR (HRcrit) was assessed from the force-frequency relationship and relaxation-frequency relationship. DP/dtmax and tau were calculated from micromanometric tracings at increasing HRs, generated by right atrial pacing. In SV @entity1 , dP/dtmax was lower than in the control group at each matched HR, and the force-frequency relationship was shifted downward. Restitution of contractility was slower in @entity1 with SV. @entity5624 was similar in both groups at lower HRs but significantly prolonged in the SV group at faster HRs. In the SV, HRcrit was significantly shifted to the left. These findings indicate impaired systolic and diastolic properties of univentricular heart, especially at increased HRs. Because these physiologic indices reflect @entity141 cycling, it is speculated that the phenomenon of @entity141 cycling may be impaired in the myocytes of univentricular hearts.

Systolic and diastolic properties of univentricular hearts in XXXX : insights from physiologic indices that reflect calcium cycling.

@entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity1 :: ('9606', 'Species') :: ['children', 'patients'] @entity1442 :: ('MESH:D020178', 'Disease') :: ['advances in surgical palliation'] @entity5624 :: ('CHEBI:36355', 'Chemical') :: ['Tau']
@entity1 :: (9606,Species) :: ['children']
