Permanent cardiac pacing in bradyarrhythmias: device coding

To describe different scopes of implantable pacemaker devices, a simple coding system is used. Most commonly, the first three or four letters of the pacing code are used. Letter 1 refers to the chamber(s) the pacemaker can pace: ‘A’ means atrial, ‘V’ means ventricular, while ‘D’ means dual atrial and ventricular pacing capabilities. Letter 2 refers to the chamber(s) of which the pacemaker can sense the electrical activity: ‘A’ means atrial, ‘V’ means ventricular, while ‘D’ means dual atrial and ventricular sensing properties. Single atrial or ventricular sensing/pacing is sometimes denoted as ‘S’. Letter 3 denotes the reaction of the pacemaker to a sensed event: ‘T’ means that a sensed event triggers the pacing activity of the device, ‘I’ means the inhibiting property of a sensed event to pacing the same chamber, while ‘D’ means combined triggered and inhibited functions. Letter 4 indicates the rate-responsive capabilities of the pacemaker, if any: ‘R’ shows that the pacemaker is a rate-responsive device. Following the first three or four letters, the ‘ICD’ label is used if the pacemaker is an implantable defibrillator. In case of cardiac resynchronization pacing, the abbreviation ‘CRT’ is applied: CRT-P for CRT pacemakers and CRT-D for CRT defibrillator devices.

Cardiac pacing: basic concepts

This chapter aims to provide an overview of the basic concepts of cardiac pacing, sufficient background, and information about the last technological advances in this field. In the first section, the physiological principles of cardiac stimulation, starting from the action potential generation and propagation, are summarized. In the second section, the essential parts and functions of an artificial pacemaker are described. Finally, in the last section some of the main pacing functions and algorithms are detailed: atrioventricular delay programming, automatic mode switch, and rate responsive sensors.

Tunable seat belt behavior in nanocomposite interfaces inspired from bacterial adhesion pili

Chaperone-Usher pilus with catch bond adhesin—a bacterial biopolymer with the ability to attach to biotic/abiotic surfaces—can act as a “molecular seat belt” that has tunable cohesive strength and rate-responsive behavior.