Astrocard® - Telemetry
Hardware and software system for in-hospital telemetry
For nearly half a century, continuous inpatient ECG monitoring has been widely used in clinical practice and has become an integral part of intensive care units. It is used to monitor cardiac rhythm disorders in patients whose condition carries a high risk of sudden, life-threatening arrhythmias.
The purpose of monitoring in this setting is to ensure an immediate response to a life-threatening arrhythmia as it develops, or to identify its warning signs and initiate preventive therapy.
Since the mid-1980s, with the introduction of dynamic ST-segment monitoring, this has also encompassed new tasks: detecting ischemic episodes in patients in the early phase of acute coronary syndromes, in patients who have undergone complicated catheter-based coronary interventions, and in patients with variant angina.
The widespread clinical use of drugs that prolong ventricular repolarization has introduced another task for inpatient ECG monitoring: monitoring QT-interval duration to help prevent torsades de pointes ventricular tachycardia.
Experience with inpatient ECG monitoring has nevertheless shown that real-time ECG monitoring is useful for certain categories of patients, although it is not mandatory in every case because their clinical conditions do not suggest a risk of life-threatening events. In such cases, monitoring can be carried out outside intensive care units, in non-intensive-care wards, using telemetry monitoring systems that allow patients a degree of physical activity and relative freedom of movement.
The following conditions fall into this category:
- Uncomplicated myocardial infarction more than 48 hours after onset
- Diagnostically indeterminate chest pain requiring further observation
- Status after uncomplicated percutaneous coronary intervention and after routine coronary angiography
- Initial stages of treatment with antiarrhythmic drugs or rate-control medication for atrial tachyarrhythmias
- Status after cardiac pacemaker implantation in patients who are not pacemaker-dependent
- Status after uncomplicated percutaneous catheter ablation for arrhythmias
- Evaluation for syncope of unexplained origin
- Terminal conditions for which resuscitation is not indicated, accompanied by arrhythmias requiring treatment because they cause discomfort
- Postoperative status in patients at high risk of myocardial ischemia
- Congenital or acquired conditions in children associated with a risk of myocardial ischemia or infarction
- Initial stages of treatment with psychotropic or other drugs that affect QT-interval duration and thereby influence the risk of torsades de pointes
- Acute neurological conditions, particularly subarachnoid hemorrhage
Telemetry central monitoring station
The telemetry central monitoring station is functionally equivalent to the central stations used for inpatient monitoring. It consists of one or more dedicated computers.
Display
Continuous on-screen display of the ECGs of monitored patients (up to 64 patients)
Printing
Immediate printing of ECG segments for different patients
Analysis
Analysis of incoming data, with alarm signals for major rhythm and conduction disorders and ST-segment changes
Storage
Storage of patient recordings in the database, with subsequent detailed retrospective processing using Holter monitoring software
Digital data transmission and signal processing, together with an original method for detecting QRS complexes and correcting baseline shifts, provide consistently high ECG recording quality (baseline drift elimination and interference suppression) and accurate detection of ST-segment depression and elevation, including for alarm generation.
For the convenience of medical staff, we have developed a mobile telemetry central monitoring station: a portable device that reproduces the central station screen and alarm signals. A physician carrying the mobile station can move freely throughout the equipped department.
Patient ECGs recorded during monitoring at the central station can be analyzed as standard 24-hour (Holter) monitoring recordings, with the following capabilities:
ECG review and presentation
- Review of 2–3-lead or 12-lead ECGs
- Presentation of analysis results as charts and tables
Automatic ECG analysis and classification
- Automatic classification of ventricular complexes by morphology
- Automatic analysis of ventricular and supraventricular arrhythmias
- Manual correction of automated analysis results
ST-segment and ischemia analysis
- ST-segment trend analysis
- Automatic calculation of heart rate, RR and ST trends
Rhythm and variability analysis
- Calculation of spectral and time-domain heart rate variability parameters
- Analysis of arrhythmia frequency
- Heart rate turbulence analysis
ECG intervals and morphology
- QT interval calculation (QTa, QTe)
- QT–RR relationship
- P-wave and PQ interval analysis
- QRST alternans analysis
Specialized algorithms and events
- Analysis of implanted pacemaker function
- Detection of nocturnal apnea episodes
Types of telemetry
recorders
Several types of wearable recorders with digital ECG data transmission over a radio link are currently available
2–3 leads
For monitoring rhythm disorders
12 leads
For monitoring ischemic changes and the QT interval
All of these recorders acquire ECG data and transmit it to the central station over the specified number of channels; they also feature an event-marking and staff-call button.
