Preventing overdiagnosis of implantable cardioverter-defibrillator lead fractures using device diagnostics.

Objectives: This study sought to use implantable cardioverter-defibrillator (ICD) diagnostics to discriminate ICD lead fractures from normally functioning leads with high impedance and from connection problems between the lead and header.

Background: ICD diagnostics facilitate identification of fractures, but there are no accepted criteria for discriminating fractures from other causes of high impedance and/or nonphysiological "noise" oversensing.

Methods: We analyzed a development set of 91 leads to construct a stepwise algorithm based on ICD diagnostics.

Isolated four-chamber working swine heart model.

Background: Isolated heart models separate cardiac characteristics from systemic characteristics with subsequent findings used in cardiac research, including responses to pharmacologic, mechanical, and electrical components. The model objective was to develop the ability to represent in situ physiologic cardiac function ex vivo.

Methods: Swine hearts were chosen over rat or guinea pig models due to their notably greater anatomical and physiologic similarities to humans.