Search results for " atrium"

�ber den Einflu� von Digitoxigenin auf das Aktionspotential des Vorhofs euthyreoter und hyperthyreoter Meerschweinchen bei experimentellen Insuffizie…

1961

An isolierten Herzohren von Meerschweinchen wurden intracellulare Aktionspotentiale unter gleichzeitiger Registrierung der Kontraktionen abgeleitet. Untersucht wurde der Einflus des Digitoxigenins nach Barbituratschadigung und unter Calciummangel bei euthyreoten und hyperthyreoten Tieren.

Isolation of the left atrial surface from cardiac multi-detector CT images based on marker controlled watershed segmentation

2006

The delineation of left atrium (LA) and pulmonary veins (PVs) anatomy from high resolution images holds importance for atrial fibrillation (AF) investigation and treatment. In this study, a semiautomatic segmentation procedure for LA and PVs inner surface from contrast enhanced CT data was developed. The procedure consists of a three dimensional marker controlled watershed segmentation applied to the external morphological gradient, followed by variable threshold surface extraction from the original intensity image. A preliminary anisotropic non-linear filtering was implemented to improve the S/N ratio of CT images. The performance of segmentation was evaluated on cardiac CT scans of 12 AF …

Effect of intravenous flecainide on atrial vulnerability in man.

1983

Sixteen patients were investigated by means of programmed atrial stimulation at two different driving rates: 100 and 120/min. All patients had an increased atrial vulnerability at both driving rates. After intravenous flecainide application (1 mg/kg body weight as a bolus followed by the same amount given by infusion over a period of 20 min) the increased vulnerability was abolished in 11 and 9 patients respectively. In the remaining patients the rate of induced atrial tachyarrhythmia decreased. These findings correlate with a significant prolongation of the effective refractory period of the right atrium and a significant shortening of the relative refractory period of the right atrium. It…

AMP-activated protein kinase (AMPK) signaling pathway: A potential mechanism involved in PAFIYAMA syndrome?

2016

Are double potentials markers of a specific zone of the atrioventricular junction in the isolated rabbit heart?

1997

A study is made of the characteristics of the atrial potentials recorded in the Koch triangle and its proximity, their variations on modifying the site of cardiac pacing, and their usefulness as markers of a distinct zone of the AV junction. In 12 isolated and perfused rabbit heart preparations an analysis was made of the endocardial atrial electrograms recorded with a multiple electrode positioned in the AV junction. The electrograms were obtained during spontaneous rhythm and on pacing at the crista terminalis (CT), interatrial septum (IAS), left atrium, and right ventricle. Double potentials were frequently obtained. On pacing at the CT, high-low double potentials (DP [H-L]) were more fr…

Effect of DB-c-AMP on mechanical characteristics of ventricular and atrial preparations of several mammalian species

1974

Conflicting results exist about the influence of cyclic N6-2′-O-dibutyryl-AMP (DB-c-AMP) on myocardial contractile force. The present study was designed to examine whether the positive inotropic action of DB-c-AMP is restricted to certain model preparations or whether it can be assumed to represent a more general effect of the drug. Therefore, the effects of DB-c-AMP on myocardial force and on various parameters of the isometric contraction curve were examined in isolated electrically driven (0.5–2Hz) ventricular and atrial preparations of several mammalian species (cat, rabbit, calf, sheep, rat and guinea-pig). The following results were obtained:

Implantation Strategy of the Atrial Dipole Impacts Atrial Sensing Performance of Single Lead VDD Pacemakers

2002

WIEGAND, U.K.H., et al.: Implantation Strategy of the Atrial Dipole Impacts Atrial Sensing Perfor-mance of Single Lead VDD Pacemakers. Intermittent atrial undersensing is observed in a considerable percentage of patients with single lead VDD pacemakers. Analyzing the 2-year data of the Saphir Multicenter Follow-Up Study, the authors investigated predictors for the occurrence of undersensing. The study included 194 patients with high degree AV block who received a VDD pacemaker system with an identical sensing amplifier. Placement strategy of the atrial dipole was left to the discretion of the implanting physician. At the final position, atrial potential amplitudes were measured during deep …

Registration and fusion of segmented left atrium CT images with CARTO electrical maps for the ablative treatment of atrial fibrillation

2005

This study aims to extract the interior surface of the left atrium (LA) and pulmonary veins (PVs) from threedimensional tomographic data and to integrate it with LA CARTO electrical maps. The separation of LA and PVs from other overlapping structures of the heart was performed processing 3D CT data by marker-controlled watershed segmentation and surface extraction. CARTO maps were then registered on the L A internal surface by a stochastic optimization algorithm based on simulated annealing. The residual registration error resulted inferior to 3 mm. The integration between electrophysiological and high resolved anatomic information of LA results feasible and may constitute a significant sup…

Left atrial strain and left atrial stiffness for early detection of cardiotoxicity in cancer patients

2021

Abstract Background Anti-cancer drugs can cause cardiovascular complications. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) are usually used to identify clinical and subclinical cardiotoxicity. Purpose The aim of our study was to assess the addictional role of left atrial reservoir strain (LAS-S) and left atrial stiffness (LASI – the ratio of E/e' to LAS-S) in identifying patients at higher risk of cardiotoxicity. Methods 102 breast cancer patients (median age 53±9.5 years), without cardiovascular diseases, were enrolled before starting chemotherapy. Electrocardiogram and transthoracic echocardiogram (conventional measurements based on EACVI recommendations;…

Giant right atrial myxoma: A rare cause of cardiovascular collapse

2019

We report the case of a patient with a giant right atrial myxoma that remained clinically silent until it almost completely obliterated the right atrium, prolapsed into the right ventricle and obstructed the tricuspid valve inflow. This case illustrates the importance of rapid surgical intervention in the setting of acute heart failure caused by tumor masses obliterating heart valves or cardiac chambers.