Temporary transvenous cardioversion and defibrillation: a new method for practical tachyarrhythmia management

The use of transvenous ICD systems and the recent advances in atrial defibrillation techniques have heightened interest in internal defibrillation. However, most shocks for induced or spontaneous arrhythmias in patients without devices are still delivered transthoracically using high energy. We describe the history of temporary internal defibrillation techniques and report the initial clinical results with a custom built disposable catheter for internal cardioversion and defibrillation. This prototype successfully converted more than 95% of 109 episodes of VT or VF in 28 patients, with biphasic energies < or = 20 J. A newer disposable catheter, using 40-wire Matrix technology as the defibrillating electrode, has design features that provide high surface area, low impedance, and low current density when compared to other leads used for similar purposes. Temporary internal cardioversion-defibrillation of induced and spontaneous arrhythmias using such catheter designs is likely to be widely applicable to patients undergoing electrophysiology procedures and to those in critical care units prone to tachyarrhythmias.