Donald Hopper

US Patent:

6411850, Jun 25, 2002

Filed:

Sep 30, 1999

Appl. No.:

09/408623

Inventors:

G. Neal Kay - Birmingham AL
Donald L. Hopper - Maple Grove MN
Jan-Pieter Heemells - Zaventem, BE
Jeff Hall - Birmingham AL

Assignee:

UAB Research Foundation - Birmingham AL

International Classification:

A61N 136

US Classification:

607 20, 607 19

Abstract:

A method for automatically determining the ventilatory (or âanaerobicâ) threshold breakpoint for adaptive rate pacing without the need for directly measuring anaerobic threshold or ventilatory threshold comprises: (a) positioning a first sensing electrode in the heart or superior vena cava of a patient carrying an implanted pacemaker, the first sensing electrode connected to the implanted pacemaker; (b) positioning a second sensing electrode in the thoracic region of the patient and spaced apart from the first sensing electrode; (c) determining the chest wall impedance of the patient between the first sensing electrode and the second sensing electrode; (d) measuring the ventilation (e. g. , the minute ventilation) of the subject from the chest wall impedance during submaximal exercise by the patient; and then (e) determining the ventilatory threshold breakpoint of the patient from the measured ventilation. In the pacemaker, the adaptive rate pacing is preferably based on measured chest wall impedance, with pacing rate increasing as exercise or metabolic activity sensed thereby increases.