نتایج جستجو برای: heart contractility
تعداد نتایج: 396124 فیلتر نتایج به سال:
A 30 year old woman with a lifelong history of severe, recurrent, vasovagal syncope became asystolic for 30 seconds after 37 minutes of 60 degrees head-up tilt. During early tilt, sympathetic activity, heart rate, left ventricular contractility, and cardiac output increased. Mean blood pressure was initially maintained. Presyncope was associated with maximal contractility and bradycardia despit...
In heart failure, reduced cardiac contractility is accompanied by blunted cAMP responses to beta-adrenergic stimulation. Parathyroid hormone (PTH)-related peptide and arginine vasopressin are released from the myocardium in response to increased wall stress but do not stimulate contractility or adenylyl cyclase at physiological concentrations. To bypass the defective beta-adrenergic signaling c...
Pubertal growth of heart was analyzed. Growth rates of "diastolic variables" of heart size were compared with that of 'systolic', and both with growth intensities of some body structures and functions that are related to cardiac growth. Longitudinal echocardiographic, ergometric and anthropometric measurements were performed in 84 healthy boys, aged 11.5 years at the beginning and 14.5 at the e...
Background: Myocardial contractile function has been studied extensively in isolated hearts using the Langendorff System. The effects of changing the heart rate on myocardial contractility have not been described. The aim of the present study was to examine the effects of changing the heart rate on studying myocardial contractility in isolated heart models using the Langendorff System, and to d...
Heart temperature affects left ventricular (LV) function and myocardial metabolism. However, how and whether increasing heart temperature affects LV mechanoenergetics remain unclear. We designed the present study to investigate effects of increased temperature by 5 degrees C from 36 degrees C on LV contractility and energetics. We analyzed the LV contractility index (E(max)) and the relation be...
Cardiac myocytes contain two constitutive NO synthase (NOS) isoforms with distinct spatial locations, which allows for isoform-specific regulation. One regulatory mechanism for NOS is substrate (l-arginine) bioavailability. We tested the hypothesis that arginase (Arg), which metabolizes l-arginine, constrains NOS activity in the cardiac myocyte in an isoform-specific manner. Arg activity was de...
The strength of the heart beat can accommodate in seconds to changes in blood pressure or flow. The mechanism for such homeostatic adaptation is unknown. We sought the cause of poor contractility in the heart of the embryonic zebrafish with the mutation dead beat. We find through cloning that this is due to a mutation in the phospholipase C 1 (plc 1) gene. In mutant embryos, contractile functio...
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