PMC5420061_01
Intracardiac tracing during defibrillation threshold testing is shown. VF was induced (1). The first shock was implemented but failed to terminate VF. Note the exclamation point at the first shock. This mark denotes overcurrent detection. A high-voltage shock could not be delivered ("0 V") (2). Subsequently, the next detection and charging sequence was executed. VF was successfully terminated using maximum shock delivery (875 V) of the "RV-CAN" shocking-vector configuration (3)(4). CAN = implantable cardioverter-defibrillator generator; DC = direct current; HV = high voltage; RV = right ventricle; VF = ventricular fibrillation.
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Subsequently, the next detection sequence was implemented and the second attempt of an 875-V shock successfully terminated ventricular fibrillation (Figure 1).
The analyzed data of defibrillation threshold testing are presented. A: Alert messages. B: The second shock vector was changed (RV-CAN), and the delivered shock was at its maximum energy (875 V). C: HV impedances and delivered shock energies are shown. CAN = implantable cardioverter-defibrillator generator; CL = cycle length; HV = high voltage; RV = right ventricle; SVC = superior vena cava; VF = ventricular fibrillation.
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