I-75
PATIENT BENEFIT FROM SEAMLESS IMPLANT
MONITORING
NENEHNO MONITORIRANJE – ALI KORISTI BOLNIKU?
Karsten Wallbrück, Jürgen Schrader
Biotronik, Erlangen, Germany
Arrived 2005-04-22, accepted 2005-04-28; ZDRAV VESTN 2005; 74: Supl. I: 75–8
Ključne besede: srčno vzpodbujanje; napredne informacij-
ske tehnologije; nadzor doma
Izvleček – Izhodišča. V starajoči se populaciji narašča števi-
lo pacientov z napravami za elektrostimulacijo srca, ki se mo-
rajo redno vračati v ambulanto na kontrolo. Zaradi tega ne-
prestano narašča delovna obremenitev kardioloških ambu-
lantnih oddelkov. Redkejši pregledi pacientov bi zmanjšali za-
nesljivost in učinkovitost zdravljenja in so zato nezaželeni.
Prepoznavanje pacientov z nevarnimi epizodami na dalja-
vo bi lahko zmanjšalo obremenitev zdravnikov v ambulant-
nih oddelkih in hkrati omogočilo hitro reakcijo pri bolnikih,
pri katerih se pokaže potreba po spremembi zdravljenja.
Vključevanje sodobne informacijske tehnologije v srčne vsad-
ke ponuja dober kompromis uporabe omejenih sredstev in
sočasne zahteve po visoko kakovostnem zdravljenju. Sistem
za avtomatično kontrolo pacientov na daljavo, ki dnevno
spremlja stanje pacienta in naprave za elektrostimulacijo
(BIOTRONIK Home Monitoring, HM) zbira podatke na inter-
netni strani, kjer so dostopni pooblaščenim strokovnjakom.
Prednosti HM pri spremljanju pacientov s srčnimi spodbuje-
valniki in implantibilnimi defibrilatorji se preverjajo v več
kliničnih raziskavah v teku. V prispevku povzemamo njiho-
ve preliminarne rezultate, ki opisujejo zmožnost sistema za
individualizacijo pogostosti pregledov v dobro pacienta in
zdravnika.
Pri pacientih s srčnim popuščanjem pogosto spremljanje s stra-
ni zdravstvenega osebja dokazano zmanjša število ponovnih
hospitalizacij, dolžino hospitalizacije in celo smrtnost bolni-
kov. V nedavno začeti raziskavi želimo ugotoviti, ali lahko s
pomočjo podatkov, zbranih s HM, napovemo ponovno hospi-
talizacijo. HM bi tako predčasno opozoril lečečega zdravni-
ka na potrebo po kontroli in spremembi zdravljenja in tako
pomagal preprečiti kasnejšo hospitalizacijo.
HM predstavlja kljub še nerešenim vprašanjem kakovosten
preskok v oskrbi bolnikov z motnjami srčnega ritma.
Key words: cardiac pacing; advanced information techno-
logies; home monitoring
Abstract – Background. Patients with electrostimulation
devices visit the hospital regularly for follow-up. The work-
load of out-patient departments is ever increasing, but a less
frequent check-up is unwanted, as it could impair reliability
and effectiveness of the therapy. A system of remote patient
monitoring might improve this situation by enabling identi-
fication of patients who benefit from a shortened time for
corrective action after any undesired event.
A completely automatic system for patient remote monitoring
has been introduced (BIOTRONIK Home Monitoring, HM).
Daily patient and device data are displayed on an internet
site which allows authorized persons to follow the parameters
trends.
Several clinical studies are presently being conducted to in-
vestigate the benefit of HM in pacemaker and implantable
cardioverter/defibrillator therapy. Preliminary results show
the system’s ability to individualize implant therapy for the
patients’ and the physicians’ benefits.
Previous studies in heart failure (HF) therapy have shown
that hospital readmission rates, hospitalisation duration and
also mortality can be reduced by patient monitoring
programs. A recently started study investigating HM in heart
failure therapy aims to define a HF-indicator that predicts a
worsening of the patient’s status leading to hospitalisation.
With such an indicator, the responsible physician could be
alerted and the patient can be called in.
Although several issues connected to Home Monitoring
remain to be solved, the time has come for a more flexible
patient management. The incorporation of modern infor-
mation technology into cardiovascular implants offers a way
to solve the conflict between limited resources and high
quality medical therapy for an aging population.
Introduction
Since the implantation of the first pacemakers, patients with
electrostimulation devices have to visit the hospital regularly
for follow-up. Besides a medical examination, the device func-
tion is checked and the therapy success is assessed with help
of the device memory. Patients have to be seen at least once a
year, mostly twice to four times.
The number of follow-up visits and the workload of out-
patient departments are ever increasing. This is due to seve-
ral factors. The number of implantations is increasing due to
increasing percentage of older people. Indication criteria are
being extended due to new study results, and completely new
therapy fields are opened, like implantable cardioverter de-
fibrillators (ICDs) fifteen years ago, and cardiac resynchroni-
zation therapy (CRT) in heart failure today. Consequently,
pressure arises to lengthen the follow-up intervals. On the
other hand, a frequent check-up might improve the therapy
in many patients. Changes of the medical status, lack of com-
pliance with prescribed drugs or simply device problems may
be unnoticed by the patient for the period between two con-
secutive follow-up visits.
ZDRAV VESTN 2005; 74: I-75–8
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A system of remote patient monitoring, supplying the phy-
sician with information on the patient without a visit in the
out-patient department, might help to shorten the time for
corrective action after any undesired event, and still reduce
the workload. Some attempts have been made to supply the
patient with simplified tools to interrogate the implant, which
transmit data by internet or telephone line. These systems
have only gained limited success because of the complicated
handling both on the patient’s and the physician’s side of the
data transmission line. The average pacemaker patient is about
70 years of age and one should not expect too much under-
standing of modern computer technology.
In the last years a completely automatic system for patient
remote monitoring has been introduced (BIOTRONIK
Home Monitoring, HM). The system comprises an implant with
a short distance radio transmission and a patient unit, which
receives the message of the implant and hands it further via
GSM (mobile) telephone network to a service center. Here
data are collected and displayed on an internet site which
allows authorized persons to follow the trends of all transmitted
parameters.
Since the time of the implant’s transmission can be set to a
time when the patient is sleeping (e. g. 3:00 am), the patient
unit can stay beside the patient’s bed. The patient’s only task
is to switch it on once. Then, unnoticed
by the patient, every night a message is
sent to the service center. In case the
service center finds a potentially risky
situation, e.g. an lead fracture, the
responsible physician is immediately
informed by fax, e-mail or SMS (1).
The HM system will gain general accep-
tance easiest if all parties involved see
their respective advantages. Both the
patients and the staff at out-patient de-
partments benefit from less frequent
out-patient visits, esp. such visits, in
which no changes of therapy are neces-
sary. The patients additionally benefit
from shorter reaction time after any
event which needs corrective action,
because HM transmits data on a daily
basis. Finally, the health insurance may
profit if the number of out-patient
visits and the number and severity of
implant associated complications is suf-
ficiently reduced.
During the course of electrostimulation
therapy, many different possible events
may happen which call for corrective
action. They may be of technical or me-
dical nature. All device-related events
which can be found during follow-up,
like lead failure or battery depletion,
can also be detected by HM. In this ar-
ticle we want to discuss experience from
ongoing clinical studies, in which
changing the medical status of the pa-
tient is in the focus of interest.
Figure 1. Components of the Home Monitoring Service: Home Monitoring implants
(top left) are available for pacing, defibrillation, cardiac resynchronisation. They
provide seamless monitoring by time triggered daily messages and event triggered
messages. The patient device (top right) relays the messages via worldwide avail-
able mobile communication technology to the Service Center (bottom right), where
the data are provided on a secure internet web site. This site can be entered by the
attending physicians at any time to monitor their patients and analyse data trends,
or events (bottom left).
Sl. 1. Delovanje sistema Home Monitoring: HM implantati (zgoraj levo) so dostopni
za stimulacijo, defibrilacijo in srčno resinhronizacijo. Implantati neprestano sprem-
ljajo stanje pacienta in enkrat dnevno ali pri neželenih dogodkih pošiljajo podatke
preko bolnikove naprave (zgoraj desno) do servisnega centra. Bolnikova naprava
za komunikacijo s servisnim centrom uporablja po vsem svetu razširjeno tehnologi-
jo za mobilno komunikacijo. Servisni center (spodaj desno) posreduje podatke na
varno internetno stran, kjer so dostopni odgovornemu zdravniku. Ta lahko dosto-
pa do strani kadar želi, spremlja svoje paciente ter analizira trende zdravstvenega
stanja ali patološke dogodke (spodaj levo).
Figure 2. The Kronos LV-T as an example for the integration
of the Home Monitoring technology: The HM antenna is com-
pletely embedded into the device header; all electronic parts
are integrated into the standard housing. Power consump-
tion is minimized, so, HM has negligible effects on the device
longevity: life long HM requires less energy than one shock.
Sl. 2. Kronos LV-T kot primer vključitve tehnologije Home Mo-
nitoring v implantat. HM antena je v celoti vgrajena v zgor-
nji del naprave (header); vsi deli elektronike so vstavljeni v
standardno ohišje. Poraba energije je
minimizirana – HM porabi v celotnem
času delovanja naprave manj energi-
je, kot se je sprosti pri enem šoku, tako
HM ne vpliva na trajnost implantata.
I-77
Methods
Today, HM is available in dual chamber pacemakers, single-
and dual-chamber ICDs, and in pacemakers and ICDs for CRT.
The technical success of message transmission has been
extensively tested and proven (2).
The medical data transmitted by HM are extracts of the
device’s memory. They are selected depending of the implant
type. Among other parameters, HM pacemakers report heart
rate, AV-conduction, ventricular and atrial extrasystolies and
tachyarrhythmia, and mode-switch. HM ICDs send data on
arrhythmia detections and therapy success, and soon also
ECG-data will be transmitted. CRT devices additionally report
percent of pacing, AV-synchrony and average and lowest
heart rates.
Several clinical studies are presently being conducted to
investigate the benefit of the HM in different patient groups.
Results
Atrial fibrillation in pacemaker patients
The first generation of dual chamber HM devices can
transmit the daily number of mode switch events, the time
the device is in mode switch, the percentage of atrio-ventricular
synchrony and the ventricular rate. Varma et al. report that
they detected AF in 29 out of 276 consecutive patients with
HM-pacemakers (3). They concluded that HM allows precise
measurement of AF burden and fast de-
cision-making concerning appropriate
anticoagulation therapy. The second
generation of HM dual chamber pace-
makers focuses even more on detection
and management of atrial tachy-
arrhythmia. The »Home-PAT« study pre-
sently investigates the possibility of
reducing the incidence of paroxysmal
atrial fibrillation with immediate re-
action after onset of each episode of AF.
ICD therapy
Implantable cardioverter/defibrillators
with HM transmit information on anti-
tachycardia therapy. An ongoing study
(HOME-ICD) investigates whether the
data transmitted by HM are suitable to
correctly decide beforehand, if during
a follow-up visit changes of therapy
(programming, drug therapy) will be
needed. From preliminary results
the authors conclude that it will be
probably possible to concentrate the
follow-up on those patients with
arrhythmic events, while the large pro-
portion of patients without events in
the study period can be seen less
frequent. The study’s final results are
awaited for summer 2005. Several cases
have already been reported in which
HM allowed fast correction after in-
appropriate tachycardia therapy (4).
Based on these promising preliminary
results, two randomized studies now in-
vestigate the extension of the standard
routine follow-up interval for ICD-
follow-up supported by HM. The stu-
dies’ endpoints comprise the number
of follow-up visits per year, mortality
and morbidity, total costs and quality of life in patients with
indication for primary and secondary prevention of sudden
cardiac death.
Heart failure
The mortality and morbidity of heart failure patients is high
even in patients with optimized medical therapy and with CRT.
Numerous studies have investigated the impact of disease
management programs in heart failure patients and have
brought evidence that improved outpatient management re-
duces hospital readmission rates and shortens hospitalisation
(5, 6). Theses effects were observed for clinic based program-
mes led by heart failure specialists, as well as for home based
programmes conducted by trained nurses. The addition of
regular automatic transmissions of weight, blood pressure and
ECG to the management programmes increases the flexibility
of patient care, while preserving the positive effects on hospi-
tal readmission and length of stay (7, 8). The TEN-HMS-study
could additionally show a significant improvement in survival
due to the regular data transmission and monitoring (9).
Important predictors for rehospitalisation and death in heart
failure patients comprise the occurrence of atrial and ventri-
cular tachycardia, and changes in mean heart rate (10, 11).
HM CRT devices transmit the patient’s average heart rate, the
heart rate at rest, duration of daily activity and parameters
indicating the success of resynchronization therapy. The
recently started Home-CARE-study investigates the question
Figure 3. Kronos LV-T resynchronisation data as an example of a Service Center
Online graphical representation of HM data: The percentage of biventricular
pacing is displayed for the last 4 weeks. The physician wanted to be alerted if the
resynchronising pacing drops to less than 70%, which happens three times during
the 4 weeks. These events are displayed in red and are marked with the »CRT«-flag
in the headline above the graph.
Sl. 3. Podatki o srčni resinhronizaciji z implantata Kronos LV-T kot primer grafične
prezentacije HM podatkov na internetni strani servisnega centra. Odstotek biven-
trikularne stimulacije je prikazan za zadnje štiri tedne. Zdravnik je želel biti opo-
zorjen v primeru, da resinhronizirajoča stimulacija pade pod vrednost 70%, kar se
je zgodilo trikrat v zadnjih štirih tednih. Ti dogodki so prikazani rdeče in označeni
s »CRT«-zastavico v naslovni vrstici nad grafom.
WALLBRUECK K, SCHRADER J. PATIENT BENEFIT FROM SEAMLESS IMPLANT MONITORING
I-78 ZDRAV VESTN 2005; 74: SUPPL I
if future hospitalisations can be predicted with the informa-
tion provided by HM. The study shall lead to the definition of
a combined HF-indicator that predicts a worsening of the
patient’s status leading to hospitalisation. With such an
indicator, the service center will be able to alert the respon-
sible physician and the patient can be called in to have drug
or device therapy optimized, to avoid lengthy hospitalisation
for decompensation.
Discussion
As mentioned above, there is increasing evidence that intensi-
fied patient care reduces morbidity and mortality even in high
risk patient groups. However, this intensified care conflicts
with limited resources and growing restrictions in the health
systems in most countries. Furthermore, this intensification
competes with broadened indications for implantable devi-
ces, especially ICDs and CRT devices, which often have to be
closely followed for optimal results (12, 13).
The dilemma’s solution suggested herein is the use of HM:
The automatic daily remote transmission of implant data, com-
bined with user selectable alert criteria and 24 hours access to
the data for the attending physician. HM has been shown to
transmit data about the patient and the implant with a high
reliability (2). If the home of the patient has a sufficient GSM
coverage, the messages of the implant reach the service cen-
ter within minutes. The data are extracted from the implant
with the focus on the most promising scenarios for improv-
ing patient management: Incidence and characteristics of atrial
and ventricular tachycardia, and indicators for worsening
heart failure. The 24 hour resolution of the transmitted data
together with automatic alert criteria enables short reaction
times. The combination of the data to a scalable trend of up
to two years allows a continuous disease monitoring with
feed-back on therapy success and side effects.
The first clinical trial in ICD therapy is close to its completion.
Preliminary results have revealed the great potential of HM
for meeting today’s demands for improved flexibility in pati-
ent follow-up without sacrificing patient safety and therapy
effectiveness (14). Hence, several randomized controlled cli-
nical trials have been started to prove the clinical benefit of
the regular automatic implant data transmission. They ma-
inly intend to improve the patients’ follow-up by shortening
of the reaction time after undesired changes in the course of
the therapy, and by avoiding unnecessary but time and re-
sources consuming routine follow-up.
Although final results are not yet available, it is anticipated
that the studies will prove a large benefit for patients and physi-
cians. More detailed analyses will reveal which subsets of pati-
ents benefit most, and in which periods. Irrespective of the
precise results, the participants in the ongoing ICD studies
are already starting to change their general clinical practice:
A large percentage of patients is routinely equipped with a
HM implant and monitored for the first period after the im-
plantation, during changes of the accompanying therapy and
towards the expected end of battery lifetime. Furthermore,
some centres have started to pre-classify their patients into
groups requiring more or less intense care according to the
HM data.
The tendency to implant HM devices is even more pronoun-
ced in heart failure patients, although the HM resynchronisa-
tion device has only become available beginning of 2005. Fol-
lowing the above mentioned results from patient manage-
ment, training, and monitoring programmes, it is generally
expected that the heart failure patient will probably benefit
from lifelong HM. The transmitted data reflects progression
and reversal of heart failure. Success and side effects of resyn-
chronisation and medication therapy are monitored. Critical
phases of the therapy may be seen much earlier than without
remote monitoring. Shortened reaction times may avoid ma-
nifestation of adverse events.
Several issues remain to be solved. The psychological impact
on the patient and relatives will be investigated. Being under
constant surveillance may give the patient a subjective feeling
of safety, or also be burdensome. The organization of the out-
patient departments must adapt to more flexible follow-up
periods, and to call patients in by telephone if HM warns of
an undesired situation. The reimbursement of the costs invol-
ved with HM, most important the necessary hardware and
the analysis of HM data by hospital staff, is still open in most
countries. Nevertheless, the time has come for a more flexible
patient management. The conflict between limited financial
and time resources and high quality medical therapy for an
aging population requires changes in the traditional way of
patient follow-up. The incorporation of modern information
technology into cardiovascular implants – as it is done with
HM – offers a reliable way to do this.
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