The purpose of this study was to assess the effects of five electronic apex locators on pacemaker function in vitro. A Biotronik Actros DR+ pacemaker was evaluated at maximum sensitivity on a flat bench top. The pacemaker lead, electronic apex locator, and oscilloscope were connected across a 150-ohm resistor. Pace monitoring was carried out with a Biotronik EPR 1000 programmer and a Tektronix ...

Advances in pacemaker technology over the last 25 years have made cardiac pacing in infants and children a safe and practical therapy. Some of the technical challenges encountered with the first permanent pacemaker implantation in children during the early 1960s have been solved with miniaturized generators, lithium batteries, noninvasive programmability, and improved placement techniques. This...

UNLABELLED A 3-month-old male infant received transvenous temporary pacemaker for acquired complete atrioventricular block. However, a right ventricle perforation by the pacing lead was found incidentally when the patient was receiving permanent pacemaker implantation nineteen days after temporary pacing. There was no pacemaker dysfunction, active bleeding or hemopericardium. The temporary paci...

We report two patients in whom breast malignancy developed in the proximity of 'migrated' pacemaker generators. These cases and the similar ones reported in the literature raise concerns whether this association is merely coincidental or whether the pacemaker generator is responsible for the occurrence in some inexplicable manner. We urge for a routine, careful examination in all patients with ...

Implantable cardiac pacemakers restore normal heart rhythm by delivering external electrical pacing to the heart. The pacemaker software is life-critical as the timing of the pulses determine its ability to control the heart rate. Recalls due to software issues have been on the rise with the increasing complexity of pacing algorithms. Open-loop testing remains the primary approach to evaluate t...

When a drug is prescribed for a patient with a permanent pacemaker or an implantable cardioverter defibrillator (ICD), consideration must be given to the potential interactions. Drug effect on pacemaker performance is usually thought to cause an increase or decrease in pacing threshold. From a practical view, Class IC drugs must be used cautiously in pacemaker patients, especially in those who ...

Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a similar set of six eyes of four morphologically different types. We have examined how each of the fou...

The cardiac pacemaker controls the rhythmicity of heart contractions and can be substituted by a battery-operated device as a last resort. We created a genetically encoded, optically controlled pacemaker by expressing halorhodopsin and channelrhodopsin in zebrafish cardiomyocytes. Using patterned illumination in a selective plane illumination microscope, we located the pacemaker and simulated t...

When pluripotency factors are removed, embryonic stem cells (ESCs) undergo spontaneous differentiation, which, among other lineages, also gives rise to cardiac sublineages, including chamber cardiomyocytes and pacemaker cells. Such heterogeneity complicates the use of ESC-derived heart cells in therapeutic and diagnostic applications. We sought to direct ESCs to differentiate specifically into ...

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...