Implantable defibrillator with fibrillation-inducing capability and method for inducing fibrillation

US5279293A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Hans Andersen · Hässelby, SE
• Martin Obel · Danderyd, SE
• Lars Wallen · Skattkärr, SE

Key dates

• Filing date: Mar 31, 1992
• Grant date: Jan 18, 1994
• Expiry date: Mar 31, 2012

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61N1/3943
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

An implantable defibrillator has a capacitor which, through a controllable switch arrangement, can either be connected to a voltage source for charging the capacitor, or connected across electrodes placed at the heart for delivering a defibrillation pulse. To calculate the minimum pulse energy required for successful defibrillation, ventricular fibrillation is first induced, so that a plurality of defibrillation attempts, with energy increasing from attempt-to-attempt can be undertaken until successful defibrillation occurs. For inducing ventricular fibrillation, the capacitor of the implantable defibrillator is connected to the voltage source until a prescribed charging voltage, which is significantly below the voltage necessary for defibrillation, is reached, and subsequently, the capacitor is disconnected from the voltage source during brief time spans at intervals within the framework of a sequence and is connected during those time spans to the electrodes. Between the time spans, the capacitor is again charged.