Paced Rhythms

Pacemakers and defibrillators are “bread and butter” devices within clinical electrophysiology. The indications for implanting these devices are myriad, but they are all derived from the same elements: the ECG and the clinical picture. Although the indications for particular types of cardiac implantable electronic devices (CIED) are beyond the scope of this text, it is within the purview of this book to discuss the important indications for pacemaker (PPM) and/or defibrillator implantation based on ECG abnormalities. Furthermore, being able to determine how the PPM is functioning (or malfunctioning) in the patient will contribute to identifying correctable pathologies. Unexplained syncope in the setting of a left bundle branch block (LBBB), loss of consciousness in the setting of a prolonged sinus pause, and third-degree atrioventricular (AV) block are only a few examples of all valid reasons for PPM implantation. This chapter will primarily focus on and educate learners about the different types of pacing and how these types of devices should manifest on the ECG.