Search results for "ventricles"

Stress Echocardiography and Strain in Aortic Regurgitation (SESAR protocol): Left ventricular contractile reserve and myocardial work in asymptomatic…

2020

Objectives: To analyze left ventricular (LV) myocardial deformation and contractile reserve (CR) in asymptomatic patients with severe aortic regurgitation (AR) at rest and during exercise, and their correlation with functional capacity. Background: The natural history of chronic AR is characterized by a prolonged silent phase before onset of symptoms and overt LV dysfunction. Assessment of LV systolic function and contractile reserve has an important role in the decision-making of AR asymptomatic patients. Methods: Standard echo, lung ultrasound, and LV 2D speckle tracking strain were performed at rest and during exercise in asymptomatic patients with severe AR and in age- and sex-comparabl…

Changes of plasma endothelin and growth factor levels, and of left ventricular mass, after chronic AT1-receptor blockade in human hypertension.

1998

The stimulation of autocrine and paracrine factors such as basic fibroblast- (bFGF) and platelet-derived (PDGF) growth factors mediates many of the growth-promoting actions of angiotensin II. The aim of this study was to evaluate the effect of chronic AT1-receptor blockade on plasma endothelin-1 (ET-1) and growth factors levels, and on left ventricular mass, in essential hypertension (EH). The study population consisted of 16 patients with mild-moderate EH, and 25 normotensive controls. In the EH patients under basal conditions, and after 3 and 6 months of chronic therapy with Losartan 50 mg/day, we measured serum levels of ET-1, bFGF and PDGF, and tumor necrosis factor (TNF). At the same t…

The Activation Pattern of the Antioxidant Enzymes in the Right Ventricle of Rat in Response to Pressure Overload is of Heart Failure Type

2003

In the left ventricle subjected to pressure overload activity, the antioxidant enzymes increased at the hyperfunctional stage. During the transition to heart failure, these enzymes are down-regulated, oxidative stress increases, and apoptosis progresses. Maladaptative activation of the antioxidant enzymes at an early stage may contribute to the intrinsic vulnerability of right ventricle to pressure overload. The authors studied changes in expression and activity of the enzymes manganese and copper-zinc superoxide dismutases, glutathione peroxidase, and catalase in the right ventricle of rat following induction of pulmonary hypertension by injection of monocrotaline. Increase in the manganes…

Dofetilide effects on the inhibition by trains of subthreshold conditioning stimuli.

2004

We investigated the electrophysiological actions of dofetilide upon the ventricular myocardium to determine whether the drug modifies the inhibitory effects of subthreshold stimuli trains upon ventricular refractoriness. In nine Langendorff perfused rabbit hearts, ventricular epicardial electrodes were used to determine the following parameters at baseline and during dofetilide perfusion (0.5 micromolar): effective (ERP) and functional (FRP) refractory periods, conduction velocity (CV), wavelength (WL), and ERP prolongation (inhibitory effect) induced by subthreshold stimuli trains (STr) at pulse frequencies of 100, 300, and 600 Hz. Dofetilide significantly prolongs ventricular refractorine…

Effects of Norepinephrine and Cardiotrophin-1 on Phospholipase D Activity and Incorporation of Myristic Acid Into Phosphatidylcholine in Rat Heart

2004

The present study is part of a project on phospholipase D (PLD) in cardiac hypertrophy and analyzed effects on PLD activity of two growth stimuli, norepinephrine (NE) and cardiotrophin-1 (CT-1), in incubated rat heart. Phosphatidylcholine (PC) was labeled by 3H-myristic acid. PLD produced 3H-phosphatidylethanol (3H-PEth) from 3H-PC in the presence of ethanol and maintained a basal formation of 3H-PEth. Short-term and long-term exposure to NE for 2 or 13 h, respectively, enhanced the formation of 3H-PEth, which was blocked by prazosin. Long-term pretreatment with NE or CT-1 increased the incorporation of 3H-myristic acid into PC, which was blocked by atenolol. When the 3H-PEth formation was …

Left ventricular non-compaction cardiomyopathy in children: Is segmental fibrosis the cause of tissue Doppler alterations and of EF reduction?

2009

Noncompaction of the ventricular myocardium (LVNC) is a rare congenital cardiomyopathy resulting from an arrest in normal endomyocardial embryogenesis. In 2002 Jenni et al. [Jenni R, Wyss CA, Oechslin EN, Kaufmann PA. Isolated ventricular noncompaction is associated with coronary microcirculatory dysfunction. J Am Coll Cardiol 2002; 39:450-454.] reported a microvascular dysfunction in 12 patients affected by non compaction: areas of restricted myocardial perfusion have been documented by scintigraphy, suggesting a reduction of Coronary flow reserve. McMahon et al reported in a recent article a reduction of TD velocities in children with noncompaction of the left ventricle, compared with nor…

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.

Rheumatoid arthritis affects left ventricular mass: Systematic review and meta-analysis.

2015

Abstract Background Cardiovascular disease represents one of the most important extra-articular causes of morbidity and mortality in patients with rheumatoid arthritis (RA). Evidences showed that several cardiac structures can be affected during the course of the disease as well as abnormalities of left ventricular diastolic filling. Contrasting data are available about left ventricular mass (LVM) involvement in patients asymptomatic for cardiovascular disease. The purpose of this systematic review and meta-analysis is to summarize the effects of RA on LVM in rheumatoid arthritis patients without cardiovascular disease. Methods A systematic research of the current case–control studies was c…

Left ventricular noncompaction presenting like a double-chambered left ventricle

2015

Echocardiography in assessing acute pulmonary hypertension due to pulmonary embolism.

1980

Eighteen patients with acute pulmonary embolism were studied with right heart catheterization and M mode echocardiography. No patient had evidence of preexisting cardiopulmonary disease; pulmonary embolism was documented with pulmonary angiography. The mean pulmonary arterial pressure correlated with the angiographic severity index of embolic obstruction (r = 0.61, p 2 , p 2 ) and in 5 patients with acute pulmonary embolism and a mean normal pulmonary arterial pressure (10.9 ± 0.4 mm/m 2 ). For all measurements the index size of the right pulmonary artery correlated with the mean pulmonary arterial pressure (r = 0.84, p