TELEMONITORING IN CARDIOLOGY
Juan C. Chachques, MD, PhD.
European Hospital Georges Pompidou. University of Paris. France.
Congestive heart failure (HF) is a serious public health problem by virtue of its prevalence, high
mortality, high morbidity, and the expense of ongoing therapy. High cardiac filling pressures and
concomitant volume overload are frequently the cause of hospital admission for heart failure. Effective
management of heart failure is partly aimed on lowering the filling pressures and improving ventricular
performance. Heart failure is associated with a high rate of hospitalization and poor prognosis.
Telemonitoring could help implement and maintain effective therapy and detect worsening HF and its
cause promptly to prevent medical crises.
Several potential strategies to control fluid volume status are used in the daily practice. Clinic visits for
assessment of filling pressure by physical examination, multiple types of noninvasive measurements,
and repeated cardiac catheterization may be employed. There is considerable cost and inconvenience
for the patient associated with these strategies and, more importantly, these methods represent
pressure and volume status only as one discrete point in time without the perturbance of daily
activities or stress. To overcome this limitation, the role of continuous ambulatory hemodynamic
information in the management of heart failure is currently under investigation.
The use of implantable hemodynamic monitors (IHMs) may assist in the management of heart failure
by providing continuous ambulatory filling pressure status for optimal hemodynamic management.
Measurement of intracardiac hemodynamic parameters has been limited to brief periods in the acute
care setting. Implantable hemodynamic monitor that is capable of measuring chronic right ventricular
oxygen saturation and pulmonary artery pressure are in development.
The devices consist of an electronic controller placed subcutaneously and two transvenous leads
placed in the right ventricle (reflectance oximeter) and pulmonary artery (variable capacitance pressure
Current devices (e.g. Chronicle® system) include an implanted monitor, a pressure sensor lead with
passive fixation, an external pressure reference (EPR), and data retrieval and viewing components.
These implantable hemodynamic monitors (IHM) continuously measures and stores multiple
intracardiac pressure measurements, heart rate, and activity. Systems are implanted using the same
technique as a single-chamber pacemaker with preferential placement of the pressure sensor lead tip
near the right ventricular (RV) outflow tract, to minimize risk of sensor tissue encapsulation.
CLINICAL FEASIBILITY STUDIES
Will determine whether telemonitoring by community-based cardiology office practices will reduce the
risk of hospital readmission (for any cause) or death after an initial “index hospitalization” for HF. The
hypothesis is that, among patients recently discharged after a hospitalization for HF, telemonitoring will
decrease the rate of rehospitalization or death over 6 months.
Will determine whether telemonitoring is capable of:
1. Reduce the rate of all-cause hospital readmission.
2. Reduce the rate of hospital readmission for HF.
3. Reduce the total number of all-cause and HF-specific hospital readmissions.
4. Increase office visits with the clinician receiving information from the telemonitoring system.
5. Improve survival after index hospitalization.
6. Reduce the cost of inpatient medical care.
7. Improve health status.
8. Improve patient satisfaction with care.
9. Improve patients’ self-management of HF.
Chronic measurement of hemodynamic parameters in the outpatient setting with implantable sensor
technology appears to be feasible. The devices are well tolerated without significant untoward effects,
and the sensors generally function well over time, providing reliable information.
PACEMAKER & DEFIBRILLATOR MONITORING
The sensitivity of patient/parent capacity to detect pacemaker problems or dysrhythmias based on
clinical findings is still a critical issue. The specificity of routine monthly telemonotoring to screen for
asymptomatic pacemaker dysfunction or new-onset dysrhythmias is actually under evaluation.
Financial charges for use of telemonitoring seem to be significantly less than comparable outpatient
Recent developed implantable cardioverter defibrillator (e.g. Lumax® ICD) contains not only a
defibrillator that can deliver life-saving electric shocks to the heart, but also integrates a technology
that monitors the functions of both the heart and the device itself.
The device automatically transfers all important diagnostic data to the cardiologist over a mobile phone
network — once a day, and immediately in the case of a critical event. The physician just needs to log
in through a secure Internet site to be informed of the patient’s current cardiac status. Moreover, the
home monitoring technology automatically sends a SMS, email or fax to the physician in case of a
critical change in the patient’s heart rhythm.
A high-definition intracardiac ECG sent over the GPRS network enables the physician to detect
arrhythmias in time. As an additional feature, the system also detects possible technical malfunctions
in the device, such as a decreasing signal quality that could impair the precision of future therapies.
The physician can clearly distinguish interfering signals from cardiac events on a computer and
contact the patient for correction of the technical problem. The cardiologist may analyze the ICD’s
programming at any time using the Internet. Another asset of this technology is the considerable
improvement of the ICDs’ service time as a result of the reduced number of electric shocks.
PEDIATRIC PACEMAKER MONITORING
Recommended as part of a comprehensive pacemaker follow-up protocol, the diagnostic and cost-
effectiveness of routine telephone monitoring (TM) in children is under evaluation. Patient age and
size with inherent age-related problems and potential inability to correlate symptoms with pacemaker
performance places the pediatric patient in a unique category, different from that of the adult.
ANOTHER APPLICATIONS OF TELEMONITORING
PULMONARY ARTERY HYPERTENSION
In patients with pulmonary artery hypertension, the desired outcome of pharmacological treatments is
a reduction of pulmonary pressure, which can be measured by right-heart catheterization or Doppler
echocardiography. However, both techniques provide only snapshots of the hemodynamic state. The
aim of telemonitoring in these cases is to test the usability of implantable hemodynamic monitors
(IHM). For this purpose, the device is implanted into patients with pulmonary hypertension who are
receiving long-term treatment with new drugs.
MONITORING SLEEP APNEA
Nearly 20% of heart-failure patients present problems with respiration. When stratified by the severity
of apnea, investigators report that patients with >15 apnea episodes per hour had a significantly lower
rate of survival from cardiac death than those with <15 apnea episodes per hour, confirming that sleep
apnea is a risk for mortality in heart-failure patients. These phases of apnea result in decreases in
oxygenation of the blood, causing problems for the heart, resulting in more arrhythmias and fatigue, as
well as also being associated with higher mortality. Normal clinical practice often does not take sleep
apnea into account because it is very difficult to recognize. However, apnea is an important risk factor
that is important to monitor and to treat.
A user-friendly home based electronic device may register weight, blood pressure, heart rate and
rhythm by means of ECG, ventilation frequency and oxygen saturation of the blood. In addition, the
patient can use a schematic code to enter details on his subjective state of health, changes of
medication and an optional contact request. Once per day the information can be sent via e-mail to a
Telemedical Centre where it is evaluated. If the critical limits of individually defined parameters are
crossed the primary care provider is promptly notified by fax. So treatment can be adjusted before
heart failure deteriorates and hospital admissions becomes necessary.
In-home communication systems allow patients to transmit information to their clinicians and provides
education to enable patients to actively participate in managing their condition. These systems use
conventional telephone lines and does not require the patient to have Internet access. Patients are
asked a pre-programmed series of questions and the system automatically uploads the responses to a
secure data center. A clinician in each practice can then log on to a secure Internet site using a Web
browser to review the patients’ responses. The system thus serves as an interface between patients at
home and their clinicians, facilitating monitoring of chronic conditions and patient education. Phone
monitoring is simple to use, does not require any equipment in patients’ homes and substantial
preliminary data suggest high patient and clinician satisfaction with its use.
Optimal management of patients with chronic heart failure has to detect emerging symptoms of a
beginning hemodynamic imbalance in time and to administer an appropriate therapy in order to avoid
decompensation and hospital admission. Telemonitoring of physiological and clinical parameters
supplies valuable information to improve health care of HF patients.
Current studies demonstrated that telemonitoring of haemodynamic data from an IHM was feasible.
Patient survey showed that the technology was user-friendly and that the training material provided
sufficient information for patients and their families to install and use the transmission equipment at
home. It also suggested that transmission success was independent of patient age or gender.
With the monitoring system, physicians and medical institutions can receive all the information about
patients while they are at home. Patient management before symptoms get to a point that they are
dangerous and would require hospitalization. By altering therapy based on the information
cardiologists receive from home, it will be possible to provide better care than simply having the
patient come in for periodic visits.
Telemonitoring, which bridges clinicians and patients with communication technology, holds promise
for closing the gap in HF care. This technology has the potential for standardized, widespread
implementation (and long-term maintenance) in the near future because it can be easily applied to
large patient populations and integrated into the current medical care system, home telemonitoring
can be easily exported to different healthcare systems across Europe. Supporting this potential,
preliminary evaluations have suggested that telemonitoring is feasible across a broad spectrum of
typical HF patients, relatively inexpensive on a per-patient basis, and highly effective in improving
A multicenter, randomized controlled trial should be organized to determine the effectiveness of a
telemonitoring strategy in decreasing hospital readmissions and death in patients with HF. Many HF
patients experience deterioration in their health status and an increase in weight and symptoms over a
period of days and weeks before ultimately presenting to medical attention and requiring
hospitalization. A frequent monitoring system can alert clinicians to the early signs and symptoms of
decompensation, providing the opportunity for intervention before the patient becomes severely ill and
requires hospitalization. Moreover, such a system can engage patients in their care and provide
instruction about beneficial self-care strategies. This intervention is not intended to substitute for
communication relating to acute care or acute, sudden changes in health status. In these cases,
patients are instructed to make direct and immediate contact with their doctor or hospital.