Heart stimulator with evoked response detector and an arrangement for determining the stimulation threshold

US7054688B1 · kind B1 · utility

Assignee

• ST. JUDE MEDICAL AB · SE

Inventors

• Asa Uhrenius · Stockholm, SE
• Berit Larsson · Danderyd, SE
• Goran Budgifvars · Spånga, SE
• Peter Andersson · Ängelholm, SE
• Feresteh Shojaei · Solna, SE

Key dates

• Filing date: Jun 9, 1999
• Grant date: May 30, 2006
• Expiry date: Jun 9, 2019

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61N1/3716
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A heart stimulator has a pulse generator which emits stimulation pulses of different amplitudes, which are delivered to a patient's heart via a lead connected to the pulse generator. The pulse generator is controlled by a control unit, in a procedure for determining a stimulation threshold value, to emit stimulation pulses of successively unidirectionally changing amplitudes. Each stimulation pulse is followed by a test pulse having a predetermined high, constant amplitude delivered in a period corresponding to the refractory period after the preceding stimulation pulse. Each test pulse has an amplitude sufficient to capture a non-refractory heart. A measurement unit is connected to the electrode lead, and measures a signal picked up by the lead after each test pulse. The measured signals are supplied to a comparator, which compares the signals following the test pulses with each other. A significant change in the measured signal after the test pulses indicates that the amplitude of the stimulation pulses has passed the threshold value.