Are modern automatic pacemakers really automatic?
Medtronic Adapta and its automatic functions

Czech version

Authors: V. Vančura; J. Bytešník; K. Lefflerová; R. Krausová; R. Čihák; P. Peichl; J. Kautzner
Authors‘ workplace: Kardiologická klinika, IKEM, Praha
Published in: Kardiol Rev Int Med 2006, 8(4): 185-191
Category: Editorial

Overview

Introduction:
The concept of automatic pacemaker that would be able to monitor the development of parameters indicative of integrity and functionality of the whole stimulation system and that would itself be able to react to changes of stimulation thresholds and amplitudes of intracardial signals, is very old. The aim of this study was to find out to what extend has the modern pacemaker approached this concept.

Methods:
The monitored patients were the patients to whom the pacemaker Adapta ADDR01 (Medtronic) was implanted between 1. 6. 2005 and 31. 5. 2006. The data was gained retrospectively from the first ambulatory check-up records. The evaluated data concerned the number of patients who present all the required data indicative of integrity and functionality of the system displayed already in the first screen of the programming device immediately after the first data input download. Data about the battery condition, the development and the current electrode impedance value, the development and the current value of the atrial and ventricular stimulation threshold and the value of intracardial signal amplitude in atriums and ventricles were considered to be the required information. It was also observed how often the measured data required overprogramming of the stimulation energy values or sensing from the regime of automatic modification to the fixed value.

Results:
27 patients (17 men) were incorporated in the study. The average age was 67.8 ± 12.1 years. 20 patients in total were implanted the pacemaker within primoimplantation, 7 patients experienced a replacement of pacemaker. In 19 cases, the primary indication of the pacemaker implantation was the sick sinus syndrome. In one case it was the carotid sinus hypersensitivity and in 7 cases it was the AV conduction disorder. During the first ambulatory check-up of all patients after implantation, the data about the battery condition, the current electrode impedance value of both electrodes and its development were displayed graphically on the first screen. In 26 patients, the data concerning the ventricular threshold value were presented. In one case, these values were missing since the threshold value was too high regarding the boundaries on which the algorithm is based. In 26 patients, the data concerning the atrial threshold values were presented. In one case this value was missing because there was an atrial fibrillation from the time of replacement up to the ambulatory check-up. The atrial sensing value was given in 12 cases, other patients had high proportion of stimulation cycles in atria. The amplitude of signal in the ventricular channel was given in 20 cases. The other patients had a high proportion of stimulation cycles. The sensing values and stimulation energy values were left in the automatic correction regime, only in the patient with unmeasured ventricular threshold the doctor considered the transformation to the fixed stimulation energy value to be appropriate.

Conclusion:
The automatic monitoring of basic parameters indicating the correct function of the stimulation system is advanced in the current models of pacemakers. Modern pacemaker can measure battery life expectancy, electrode impedance values, atrial and ventricular stimulation threshold, as well as sensing values. These values are then displayed on the screen of the programming device immediately after the data input download. If the measured sensing values or stimulation threshold values are not displayed on the first screen, it is usually the result of high stimulation threshold, presence of atrial fibrillation or low number of scanned cycles during a higher proportion of stimulation in the respective cavity. The automatic sensing values and stimulation energy values correction regime seems to be appropriate to the majority of patients.

Keywords:
pacing – automatic pacemaker – pacemaker Adapta – sensing – stimulation threshold

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