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BACKGROUND The aim of the present work was to study the profile of the rapid delayed rectifier potassium current (I (Kr)) and the inward rectifier potassium current (I (K1)) during ventricular repolarization as a function of action potential duration and rate of repolarization. METHODS Whole cell configuration of the patch clamp technique was used to(More)
BACKGROUND Although pharmacological block of the slow, delayed rectifier potassium current (IKs) by chromanol 293B, L-735,821, or HMR-1556 produces little effect on action potential duration (APD) in isolated rabbit and dog ventricular myocytes, the effect of IKs block on normal human ventricular muscle APD is not known. Therefore, studies were conducted to(More)
Small-conductance calcium-activated potassium channels (SK channels) have a significant role in neurons. Since they directly integrate calcium handling with repolarization, in heart their role would be particularly important. However, their contribution to cardiac repolarization is still unclear. A previous study reported a significant lengthening effect of(More)
BACKGROUND AND PURPOSE The aims of the present work were to study the mechanism of the reverse rate dependency of different interventions prolonging cardiac action potential duration (APD). EXPERIMENTAL APPROACH The reverse rate-dependent lengthening effect of APD-prolonging interventions and the possible involvement of I(Kr) (rapid component of the(More)
Dilated cardiomyopathy (DCM) is a multifactorial disease characterized by left ventricular dilation that is associated with systolic dysfunction and increased action potential duration. The Kir2.x K⁺ channels (encoded by KCNJ genes) regulate the inward rectifier current (IK1) contributing to the final repolarization in cardiac muscle. Here, we describe the(More)
Ivabradine is a novel antianginal agent which inhibits the pacemaker current. The effects of ivabradine on maximum rate of depolarization (V(max)), repolarization and spontaneous depolarization have not yet been reported in human isolated cardiac preparations. The same applies to large animals close to human in heart size and spontaneous frequency. Using(More)
The species-specific determinants of repolarization are poorly understood. This study compared the contribution of various currents to cardiac repolarization in canine and human ventricle. Conventional microelectrode, whole-cell patch-clamp, molecular biological and mathematical modelling techniques were used. Selective IKr block (50-100 nmol l(-1)(More)
OBJECTIVES We examined the Sorin Perceval S artificial biological valve implantation techniques, and present the initial experiences in our unit. METHODS In the last 1.5 years, 27 patients had been implanted with Sorin Perceval S biological arteficial valve due to aortic valve disease. The device was mainly used in high-risk patients, in reoperative(More)
The roles of the alveolar and systemic CO₂ on the lung mechanics were investigated in dogs subjected to cardiopulmonary bypass. Low-frequency pulmonary impedance data (Z(L)) were collected in open-chest dogs with an alveolar CO₂ level (FA(CO₂)) of 0.2-7% and during systemic hypercapnia before and after elimination of the vagal tone. Airway resistance(More)
Coronary arteries isolated from human, porcine, and canine hearts were depolarized with potassium chloride and relaxed by cromakalim (0.0125-10.0 micromol/L) at low (1.5 mmol/L) and high (7.5 mmol/L) extracellular calcium concentration ([Ca(2+)]( o)). At low [Ca(2+)](o), cromakalim (1 micromol/L) relaxed the coronary arteries with the order of porcine >(More)