In the adult, the heart rate is driven by spontaneous and repetitive depolarizations of pacemaker cells to generate a firing of action potentials propagating along the conduction system and spreading into the ventricles. In the early embryo before E9.5, the pacemaker ionic channel responsible for the spontaneous depolarization of cells is not yet functional. Thus the mechanisms that initiate ea...

A 55-year-old female patient with earlier diagnosis of cardiac cirrhosis and mitral valve implantation was admitted with complaints of weakness and dizziness. She had undergone VVIR pacemaker implantation 9 years earlier due to low ventricular rate atrial fibrillation and had generator replacement procedure 3 months previously. Electrocardiogram indicated pacemaker dysfunction due to failure to...

OBJECTIVES English springer spaniels (ESS) are one of the most frequently presented breeds for pacemaker implantation in the UK and may do so at an early age. In comparison to dogs of other breeds (non-ESS) presenting for pacemaker implantation, cardiac troponin I (cTnI), the outcome and survival of ESS were investigated. METHODS Case records of dogs receiving pacemaker implantation were retr...

Background/Aims We investigated the role of representative endoplasmic reticulum proteins, stromal interaction molecule 1 (STIM1), and store-operated calcium entry-associated regulatory factor (SARAF) in pacemaker activity in cultured interstitial cells of Cajal (ICCs) isolated from mouse small intestine. Methods The whole-cell patch clamp technique applied for intracellular calcium ions ([Ca...

OBJECTIVE To study the potential interactions in patients with endocardial permanent pacemakers and non-thoracotomy implantable cardioverter defibrillator (ICD) systems. DESIGN Case series and cohort study. SETTING Tertiary referral centre. PATIENTS Fifteen consecutive patients with both endocardial pacemakers (12 dual chamber and three single chamber) and non-thoracotomy ICD systems. M...

BACKGROUND The purpose of this study was to investigate the electrophysiological effects of dexmedetomidine on pacemaker cells in sinoatrial nodes of rabbits. METHODS Healthy rabbits were anesthetized intravenously with sodium pentobarbital, and the hearts were quickly dissected and mounted in a tissue bath. Machine-pulled glass capillary microelectrodes which were connected to a high input i...

BACKGROUND A recently completed trial, the Canadian Trial of Physiological Pacing (CTOPP), showed that physiological pacing did not significantly reduce mortality, stroke, or heart failure hospitalization, but it did show that atrial fibrillation occurred less frequently in patients with physiological pacing. Many pacemaker patients experience only transient bradyarrhythmias with an adequate un...

Although many studies show that thromboxane A(2) (TXA(2)) has the action of gastrointestinal (GI) motility using GI muscle cells and tissue, there are no reports on the effects of TXA(2) on interstitial cells of Cajal (ICC) that function as pacemaker cells in GI tract. So, we studied the modulation of pacemaker activities by TXA(2) in ICC with whole cell patch-clamp technique. Externally applie...

Pacemaker lead infection is a rare condition, most often occurring when intervention is needed after pacemaker implantation. Diagnosis is by blood cultures and confirmation by transoesophageal echocardiography; transthoracic echocardiography is often inadequate. A literature review indicated the microorganism most responsible for late lead infection is Staphylococcus epidermidis (which can grow...

Embolization of the sinus node artery was accomplished in dogs by injecting rapidly hardening vinyl latex into the sinus node artery. Embolization immediately shifted the pacemaker to a junctional focus; however, with time postoperatively, the pacemaker shifted to an atrial site. Variable episodes of pacemaker failure, sinoatrial block, junctional rhythm, wandering atrial pacemaker and idiovent...