Search results for " Atri"

Stimulatory effects of DB-c-AMP and adrenaline on myocardial contraction and 45Ca exchange. Experiments at reduced calcium concentration and low freq…

1973

The effects of adrenaline (2.2×10−6 M) and cyclic N6-2′-O-dibutyryl-adenosine-3′,5′-monophosphate (DB-c-AMP; 10−3 M) on mechanical performance, 45Ca uptake and total tissue calcium concentration were investigated in electrically stimulated left auricles isolated from female rats weighing 180–220 g. The experiments were performed at reduced [Ca]e of 0.45 mM and at various frequencies of stimulation (0–120 beats/min). In the first series of experiments 45Ca incubation time was 5 min. Under these conditions DB-c-AMP as well as adrenaline enhanced contractile force to 300–450% of the control values at all frequencies tested (Fig.1). This increase in contractile force was accompanied by a signif…

Effects of inhibitors of cGMP-dependent protein kinase in atrial heart and aortic smooth muscle from rats

1995

Several activators of cGMP-dependent protein kinase (protein kinase G) such as 8-Br-cGMP reduced force of contraction in rat left atria. Inhibitors of protein kinase G antagonized the negative inotropic effect of 8-Br-cGMP but not of acetylcholine in atria. However, the acetylcholine-induced relaxation in aortic rings was significantly inhibited by protein kinase G inhibition. It is concluded that the reduction by 8-Br-cGMP of force of contraction in atria is related to activation of protein kinase G. In response to acetylcholine, activation of protein kinase G is probably a major step in smooth muscle relaxation but is not involved in the reduction of force of contraction in atria.

Silent atrial fibrillation during the acute phase of myocardial infarction

2013

0283: Correlation between N-terminal pro-natriuretic peptide levels and left atrial size in patients with left ventricular systolic dysfunction

2014

BackgroundElevated N-terminal Pro B-type Natriuretic Peptide (NT Pro-BNP) levels are correlated with the severity of left ventricular systolic dysfunction and left ventricular filling alterations. Besides, left atrial (LA) size is believed to reflect chronic diastolic dysfunction.AimEvaluate the relationship between NT Pro-BNP and LA size.Methods81 patients (77.7% males; mean age, 61.55±15 years), with left ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] 20cm2 was 1188pg/mL (area under the receiver-operating characteristic curve [AUC] 0.83 [0.71–0.93], p<0.0001, sensitivity 77.6%, specificity 75%).ConclusionThe present study shows that plasma NT Pro-BNP levels is…

Red blood cell distribution width: A marker of anisocytosis potentially associated with atrial fibrillation

2019

The incorporation of biomarkers in the actually used risk scores seem to be helpful for early identifying atrial fibrillation (AF) patients at higher risk. The aim of this critical review of the scientific literature is to investigate the potential clinical significance of red blood cell distribution width (RDW) in AF. A systematic electronic search was carried out to identify all articles describing an epidemiological association between RDW and AF in adult human populations. Data abstraction was conducted on a final number of 35 articles (13 cross-sectional, 12 prospective and 10 retrospective studies). The results of these epidemiological investigations were all virtually concordant to e…

A coronary right fistula canalized in a small accessory right atrial chamber.

2007

The coronary artery fistulas are rare congenital anomalies with a very low incidence. These can be symptomatic or asymptomatic because the hemodynamic consequences of the fistula vary and depend on the shunt dimensions. Discordant opinions instead are present in the literature for the defect closing in asymptomatic patients. Here, we describe a patient affected by a coronary right fistula canalized in a small accessory right atrial chamber. During follow-up, we observed a progressive dilatation of the right coronary artery (maximum diameter 10.3 mm) with hemodynamic overload of the right sections.

Tetrodotoxin slightly shortens action potential duration in ventricular but not in atrial heart muscle.

1988

Tetrodotoxin (TTX), at concentrations significantly decreasing maximal upstroke velocity (dV/dtmax) of the action potential, exerted variable effects on action potential duration (APD) in different myocardial preparations. APD was virtually unchanged by tetrodotoxin in the guinea pig atrium, but slightly shortened in the guinea pig ventricle at maximally effective concentrations. In the human ventricle, both dV/dtmax and APD were reduced in the same concentration range of TTX. These results suggest that a TTX-sensitive sodium current significantly contributes to the repolarization phase of the action potential in ventricular but not in atrial heart muscle.

The role of the renin-angiotensin system in atrial fibrillation and the therapeutic effects of ACE-Is and ARBS

2008

Atrial fibrillation (AF) is the most common rhythm disturbance in medical practice and represents a very expensive health problem. AF can be managed with the prevention of thromboembolism and either a rate control of rhythm strategy. As both strategies have important limitations, probably a preventative strategy in patients at risk of developing arrhythmia can be a more attractive option. The renin-angiotensin system (RAS) seems to be involved in the genesis of arrhythmia by the following two mechanisms: 1. the induction of atrial fibrosis and structural remodelling by mitogen-activated protein kinase (MAPK) expression and reduction of collagenase activity; 2. the induction of electrical re…

Giant left atrium: a condition that is rarely seen today.

2008

Today, giant left atrium is a condition that is rarely observed in clinical practice and diagnosis can be missed. It is prevalent in patients with rheumatic heart disease that has decreased considerably in industrialized countries in the last two decades. However, the immigration flow in the current era can revive its incidence.

Pharmacological Therapy in Children with Atrial Fibrillation and Atrial Flutter

2008

Heart rhythm disorders in children are not different, on electrocardiographic trace, from heart rhythm disorders in adults with the exception of incidence which is different according to the age. Paticularly, atrial flutter (FlA) and fibrillation (FA) are very uncommon arrhythmias in the general pediatric population. Generally atrial fibrillation and atrial flutter, in our experience, is a temporary heart rhythm disturbance connected to specifical and resovable reasons with the exception of Fontains surgical correction of congenital heart diseases or cardiopathies with dilatation of both atria. Presenting symptoms, symptom history (e.g., frequency, duration, and severity), risk assessment, …