BACKGROUND Sinus bradycardia is frequently observed in patients treated with crizotinib, a receptor tyrosine kinase inhibitor used for the treatment of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC). We investigated whether crizotinib could influence heart rate (HR) through direct cardiac effects. METHODS The direct effect of crizotinib on HR was studied using ...

Objectives: Dual pathways have a determinant role in the occurrence of atrio nodal tachyarrhythmia (AVNRT). The aim of present study is to determine the role of slow pathway (SP) in the concealment zone and protective role of AV node during atrial fibrillation (AF). Material &Methods: In 7 isolated nodal rabbit preparation zone of concealment and concealed conduction is quantified by Specif...

The aim of the study was to identify ion channel transcripts expressed in the sinoatrial node (SAN), the pacemaker of the heart. Functionally, the SAN can be divided into central and peripheral regions (center is adapted for pacemaking only, whereas periphery is adapted to protect center and drive atrial muscle as well as pacemaking) and the aim was to study expression in both regions. In rabbi...

BACKGROUND The hyperpolarization-activated current, If, plays an important role in sinoatrial node (SAN) pacemaking. Surprisingly, the distribution of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in human SAN has only been investigated at the mRNA level. Our aim was to define the expression pattern of HCN proteins in human SAN and different atrial regions. METHODS AND RE...

Pacemakers were implanted in 10 of 14 patients with dizziness and syncopal episodes of long duration, due to sino-atrial block. Paroxysmal supraventricular tachycardia, notably atrial fibrillation, had occurred in 6 patients. Medical treatment was unsatisfactory in 3 of these and pacemaker therapy was given. This abolished both syncope and paroxysmal tachycardia. Sinoatrial block and supraventr...

In atrial and ventricular cells from hearts of hatched chicks, acetylcholine reduced the overshoot and the duration of action potentials recorded in normal Tyrode's solution (5.4 ITIM K). This effect of acetylcholine is attributed to inhibition of the slow inward current-dependent portion of the action potential because acetylcholine reduced the overshoot, rate of rise, and duration of the Ca/N...

In this study cardiac tissue is stimulated electrically through a small unipolar electrode. Numerical simulations predict that around an electrode are adjacent regions of depolarization and hyperpolarization. Experiments have shown that during pacing of resting cardiac tissue the hyperpolarization is often inhibited. Our goal is to determine if the inward rectifying potassium current (IK1) caus...

A case of atrial tachysystole with apparent exit block is reported in which the basic cycle length of atrial activity is 260 msec. Simultaneous right intra-atrial electrograms show cycle lengths of 510 to 780 msec which are roughly multiples of 260 msec establishing the diagnosis of exit block. Rapid atrial stimulation (1,200/min) to overdrive the rapid ectopic atrial pacemaker was only transie...

TRPM4 forms a non-selective cation channel activated by internal Ca(2+). Its functional expression was demonstrated in cardiomyocytes of several mammalian species including humans, but the channel is also present in many other tissues. The recent characterization of the TRPM4 inhibitor 9-phenanthrol, and the availability of transgenic mice have helped to clarify the role of TRPM4 in cardiac ele...

variance, such as intense physical exercise, advanced heart failure or diabetic neuropathy. Spectral analysis of RR variability does not measure tonic nerve activity of any of the two autonomic outflows, but only provides an estimate of the continuous interaction between sympathetic and vagal modulatory activities with the sino-atrial node function, examined in closed loop conditions. Large sca...