GUARDIAN the world's first and only heart attack warning system

Alerts in real-time even without symptoms

The GUARDIANis a cardiac monitoring device which monitors the patient 24/7 looking for ST-segment changes. When a change is detected, indicating a potential ACS event, the patent is alerted to seek emergency help. Used as an adjunct to symptoms, the GUARDIAN provides another layer of protection and alerts patients even in the absence of symptoms.

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The GUARDIAN is implanted in a similar manner to a single-chamber ventricular pacemaker. Following implantation, the GUARDIAN is set to collect data passively over a two-week period. At the end of the two-weeks, adjustments to the detection and alarm criteria are made (much like a post-implant follow-up for a pacemaker). The GUARDIAN then starts monitoring the patient 24/7.

Patients rely on symptoms to seek medical care but what if they don’t recognise the symptoms or there are none?

guardian unsure symptoms

Typical symptoms

Patients are generally aware of typical ACS event symptoms such as chest pain.

guardian atypical symptoms

Atypical symptoms

Patients often ignore atypical symptoms experienced during an ACS event.

guardian absent symptoms

No symptoms

Patients may experience no symptoms during an acute coronary syndrome event (a silent event).

Real-time alerts with the GUARDIAN algorithm

The GUARDIAN’s operation is based on the relationship between ST-segment changes and ischaemia. The GUARDIAN’s algorithm continuously monitors the patient’s heart signal for ST-segment changes and provides notification using triple-modality alerting when an abnormal change occurs.

The abnormal change is measured by “ST-Shift”. This shift is the difference between the patient’s current ST-segment and their base-line (learnt from data collected over the previous 24-hours). These shifts can be detected even when a patient is experiencing no symptoms.

Example patient alarm results, with the GUARDIAN implant1.

Patients with prior acute coronary syndrome (ACS) events, who remain at high risk, no longer have to rely on symptoms alone1

The warning alarm from the GUARDIAN ensured that the patient was admitted to the hospital early and was able to receive critical care treatment as soon as an event was detected.

*First Emergency Alarm – Device warning alerted patient to seek immediate medical treatment
**Second Emergency Alarm – Patient’s ruptured plaque confirmed by angiogram and other diagnostic tests


1. Fischell, T.,  Fischell, R., Avezum, A., et al. Initial Clinical Results Using Intracardiac Electrogram Monitoring to Detect and Alert Patients During Coronary Plaque Rupture and Ischemia. JACC. 2010 Sep 28; 56(14):1089–98

2. Gibson, M., Holmes, D., Mikdadi, G., et al. Implantable Cardiac Alert System for Early Recognition of ST-Segment Elevation Myocardial Infarction. JACC. 2019; 73(15):1919-1927.

The GUARDIAN is not available for supply in Australia and is currently not included on the Australian Register of Therapeutic Goods.