We have evaluated clinically a rate‐responsive pacemaker which uses the evoked QT principle as indicator of physiological demand. This pacemaker is microprocessor‐based and fully programmable noninvasively through radiofrequency coupling to an external microcomputer. To date this system has been implanted in 15 patients. With this QTsensing pacemaker the ra te response to exercise was smooth and progressive, and gradually returned to the basic paced rate after termination of activity. Physiologic rate responsive pacing resulted in significant improvement in exercise tolerance and a 40% increase in cardiac output when compared to fixedrate pacing in 8 patients. This initial experience confirms the possibility of obtaining a physiological response to exercise using a pacing system dependent only on a unipolar electrode which is independent of the problems of atrial activity and sensing. Rate responsive pacing might prove to be a useful alternative to atrial synchronous systems, and particularly advantageous in those patients whose sinoatrial function is abnormal or who suffer from atrial arrhythmias.
[1]
G. Nikolić,et al.
Sudden Death Recorded During Holter Monitoring
,
1982,
Circulation.
[2]
R. Donaldson,et al.
The Ventricular Endocardial Paced Evoked Response
,
1983,
Pacing and clinical electrophysiology : PACE.
[3]
J. Floras,et al.
Adaptation of hypertensives to treatment with cardioselective and non-selective beta-blockers. Absence of correlation between bradycardia and blood pressure control, and reduction in slope of the QT/RR relation.
,
1980,
British heart journal.
[4]
A. Rickards,et al.
Relation between QT interval and heart rate. New design of physiologically adaptive cardiac pacemaker.
,
1981,
British heart journal.
[5]
A Wirtzfeld,et al.
Central Venous Oxygen Saturation for the Control of Automatic Rate‐Responsive Pacing *
,
1982,
Pacing and clinical electrophysiology : PACE.