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Physiological Programmability in
Artificial Pacemakers
Almeida Rui, Manuel Sequeira; Lima Jr., José Dantas.
Instituto de Moléstias Cardiovasculares de Cascavel (IMCC) e Universidade
Estadual do Oeste do Paraná (UNIOESTE), Cascavel, Paraná, BRASIL
RESUMO
SUMMARY
Objective: To verify the benefits given by all the parameters and programmable functions of the artificial pacemakers (AP),
that give a more physiological stimulation and appropriate to the patient's necessities, which depends on the knowledge and use
of the functions and parameters given by the pulse generators.
Material and Method: Twenty-five patients were studied (13F/12M), with AP with a mean age of 62.9 years, for a period post
implantation of 12.4 months. The indication for AP implant was in all cases complete atrioventricular block. All generators had
movement sensors. Two evaluations were performed in the post implant period. On the first one, with the basic program, a
verification of the following parameters was performed: electric parameters, myopotential inhibition, statistic within the
generator and the advanced programs. On the second evaluation the changes made to the original program, and the
percentage of events sensed and stimulated by the AP were analyzed.
Results: The P and R waves, ventricular threshold and impedance values obtained at the first evaluation, were respectively:
1.50±1.85 mV, 12.55±4.35 mV, 0.76±0.29 V, 530.64±93.27 ohms. Two pulse generators were in VDD mode, eight in VVI and
15 in VVIR. The night program was always on, with a mean duration of 7.2 hours. In 13 AP, with a unipolar lead, there was
myopotential inhibition and the sensibility was reduced. The statistical data, during the basic program showed that 19.4% were
sensed events (SE) and 80.6% were paced events (PE). During the advanced program, the percentage of SE was 23.4% and
the PE was 76.6%.
Conclusion: The change in the original pulse generator program done in these patients, presents benefits within the
physiological rhythm, therefore having a smaller competition with the spontaneous activity and showed a reduction in PE. With
these in mind we conclude that these pulse generators should have a greater longevity.
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INTRODUCTION
Although we don't have a national industry, of artificial pacemakers, we have almost all the worldwide
manufacturers working here in Brazil nowadays, therefore we have innumerable models of leads and generators
available to satisfy our needs. The manufacturer or the standard programming, of the generators, rarely attends the
needs of our patients. In the majority of the cases the generators programming adjust is individualized and depends
on a more detailed follow-up including especially the statistic functions. The enterprises that present in Brazil the
same products commercialized in the origin countries have these statistic functions very developed and confident. The
objective of this study is to check the benefits provided by an adequate and large pacemaker programming, and that
provides a physiologic response approach of the patients. Among these parameters, will be evaluating stimulation
mode, basic rate, hysteresis, night program, sensor for frequency adaptation and others.
BASIC PROGRAMMING
The basic programming refers to the standard program that goes along with the pacemaker when it is implanted
and during the acute phase.
EXTENDED PROGRAMMING
The extended programming is realized when the scar process is considered chronic or the variations that will occur
will not be significant. In these moment the electric parameters and the pacemaker statistic are checked and, based
on these information, the pacemaker is programmed ( Figure 1 ).
Fig. 1: Basic programming (PREV.) and extended programming (NEW)
MATERIAL AND METHODS
At the "Instituto de Moléstias Cardiovasculares de Cascavel", 25 patients (13 F/12 M) with artificial pacemaker,
implanted between October of 1999 and August of 2000, with an mean age of 62.92 ± 17.78 years, were studied
during a postoperative medium period of 12.48 ± 5.03 months. The implant indication in all the cases was complete
heart block.
All the implanted generators had movement sensor (accelerometer). Among these pacemakers, 23 were ventricular
single chamber and two were dual chamber with single lead. Two follow-ups were realized in the postoperative period
with the system PMS 1000 (Biotronik GmbH & Co.). In the first follow-up, with the basic programming, we checked:
the electric parameters, the myopotential inhibition, the statistic contained in the generator memory and the
extended programming was activated. In the second follow-up we checked the statistics results with the extended
programming. In these second follow-up we analyzed: the changes done in the programming and the percentage of
sensed and paced events by the pacemakers.
RESULTS
The mean values of P and R wave, ventricular stimulation threshold and impedance, checked in the first follow-up,
were respectively: 1.50 ± 1.85 mV; 12.55 ± 4.35 mV; 0.76 ± 0.29 V; 530.64 ± 93.27 Ohms. The stimulation mode
of the two dual chamber generators with single lead remained in VDD (8%). From the 23 ventricular single chamber
generators, 8 remained in the mode VVI (32%) and 15 were programmed in the mode VVIR (60%). In all the cases
the night program was activated with a medium duration of 7.20 ± 0.69 h. The hysteresis was activated in one case.
In six cases the basic frequency was reprogrammed. In the cases (six) that the implanted lead had two poles, the
sense and pace polarity was programmed to bipolar. In 22 cases the generators sensibility was reduced. In 13 (68%)
pacemakers, with unipolar lead occurred myopotential inhibition. During the R wave test, five patients (20%) were
considered dependents (didn't show ventricular intrinsic beats with a frequency as low as 30 bpm), four patients
(16%) showed intrinsic beats between 30 and 40 bpm, six patients (24%) showed intrinsic beats between 40 and 50
bpm, two patients (8%) showed intrinsic beats between 50 and 60 bpm and eight patients (32%) showed intrinsic
beats with a frequency, higher than 60 bpm. The statistics data during the basic programming showed that 19.4%
were sensed events (Vs) and 80.6% were paced events (Vp). During the extended programming, the percentage of
Vs was 23.4% and Vp 76.6%.
DISCUSSION
One of the patients with dual chamber generator and single lead, showed atrial undersensing and far-field. We had
to increase the atrial sensibility despite the far-field. However, no alteration in the rhythm occurred due to this
interference because it was contained inside the atrial refractory period. No patients with VDD programming showed
cross-talk.
The activity sensor, or accelerometer, was activated in patients that didn't show myocardiopathy, were active and
related tiredness after efforts, and demonstrated high stimulation percentage (> 80%) in the pacemaker event
counter ( Figure 2 ).
Fig 2: Pacemaker event counter
Despite these parameters being activated in the extended programming, in 60% of the patients, there was an
increase of 4% in the sensed events total medium value, and a proportional reduction in the stimulation. This
compensation, obviously, occurred because of the night program activation that reduced on average 10 ppm in the
basic rate during a medium time interval higher than seven hours (29%). The average high age (62 years) also could
contribute for this compensation, because the activity level in advanced ages decay. In the case of night activity in
patients without any chronotropic response the accelerometer will answer, but with a minor sensibility. We can have
an idea of the alterations caused by the extended programming in the Figures 3 and 4.
Fig 3: Basic (up) and extended programming histograms
Fig 4: Basic and extended programming 24 hours monitor
The test to verify the myopotentials interferences appeared extremely important, due to the fact that 68% of the
patients with unipolar leads showed myopotentials interferences in the standard sensibility (2.5mV). The patient was
monitored in a peripheral derivation opposite of the generator implant (D3 and D2 for those with right and left side
implants, respectively). Movements of the arm activated pectoral musculature, in the side of the generator. In the
case of interference the sensibility was reduced until the complete elimination of the interference. The safety margin
maintained in the sensibility programming was always higher than 100%.
CONCLUSION
The programming achieved in the studied patients showed the inherent clinical benefits to the physiologic rhythm,
allowed a minor competition with the spontaneous activity and showed a reduction in the stimulated events
percentage. Therefore, we presuppose an increase in the generators battery longevity and, consequently, a higher
period without the exchange of the generator necessity, with advantages for the patient and the contribution to the
costs reduction with these devices.
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Programação Fisiológica em Marcapassos Cardíacos Artificiais
RESUMO
Objetivo: Verificar os benefícios proporcionados pelos diversos par âmetros e funçõ es programáveis dos marcapassos cardíacos
artificiais (MCA), que propiciam uma estimulação mais fisiológica e apropriada às necessidades dos pacientes, o que depende do
conhecimento e uso das funçõ es e parâmetros disponíveis nos geradores.
Material e Método: Foram estudados 25 pacientes (13F/12M) portadores de MCA com média de idade de 62,9 anos por um
período médio pós-implante de 12,4 meses. A indicação de implante em todos os casos foi BAVT. Todos os geradores
implantados apresentavam sensor de movimento. Realizaram -se duas avaliações no período pós-implante. Na primeira
avaliação, com a programaçã o básica, foram verificados: os parâmetros elétricos, a inibiçã o por miopotenciais, a estatística
contida na memória do gerador e ativada a programaçã o estendida. Na segunda avaliaçã o verificou-se o resultado da estatística
com a programação estendida. Foram analisadas: as mudanças feitas na programação e o percentual de eventos sentidos e
estimulados pelos MCA.
Resultados: Os valores médios da onda P, onda R, limiar de estimulação ventricular e imped ância, verificados na primeira
avaliação, foram respectivamente: 1,50±1,85 mV, 12,55±4,35 mV, 0,76±0,29 V, 530,64±93,27 ohms. Dois geradores ficaram
em VDD, oito permaneceram no modo VVI e 15 foram programados no modo VVIR. O programa noturno foi sempre ligado com
uma dura ção média de 7,2 hs. Em 13 MCA com eletrodo unipolar ocorreu inibiçã o por miopotenciais e a sensibilidade foi
reduzida. Os dados estatísticos durante a programaçã o básica mostraram que 19,4% foram eventos sentidos (Vs) e 80,6 %
foram eventos estimulados (Vp). Durante a programaçã o estendida, o percentual de Vs foi de 23,4% e Vp de 76,6%.
Conclusão: A programação realizada nestes pacientes apresenta os benef ícios cl ínicos inerentes ao ritmo fisiol ógico, permite
uma menor competiçã o com a atividade espontânea e mostra redução no percentual de eventos estimulados. Com isto
pressupomos um incremento na duraçã o da vida útil da bateria dos geradores.
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2nd Virtual Congress of Cardiology
Dr. Florencio Garófalo
Dr. Raúl Bretal
Dr. Armando Pacher
Steering Committee
President
Scientific Committee
President
Technical Committee - CETIFAC
President
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Copyright© 1999-2001 Argentine Federation of Cardiology
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