Ambulatory ECG monitoring and exercise-test risk findings
THE CONTEXT
Ambulatory ECG extends rhythm recording beyond a standard ECG snapshot. The target material also lists indications and high-risk findings for exercise testing.
Continuous ambulatory recording
•
Portable digital recorders usually provide continuous limb-lead ECG recordings for 1–7 days.
•
The main indication is suspected arrhythmia, including intermittent palpitation, dizziness or syncope. A standard ECG may miss an intermittent arrhythmia because it records only a snapshot.
•
Ambulatory ECG can also assess rate control in atrial fibrillation and detect transient myocardial ischaemia through ST-segment analysis.
Monitoring infrequent symptoms
•
For infrequent symptoms, a patient can activate a special recorder during an episode and place it on the chest wall to record the rhythm. Some devices transmit recordings electronically to hospital.
•
For very infrequent but potentially serious symptoms, such as syncope, a loop recorder resembling a leadless pacemaker can be implanted subcutaneously to record rhythm for 1–3 years.
Exercise-testing indications
•
Exercise testing assesses symptoms and severity of exertional angina and assists the diagnosis and risk stratification of stable angina.
•
It also assesses outcomes after coronary revascularisation and diagnoses exercise-induced arrhythmias while evaluating their treatment.
High-risk exercise-test findings
•
Ischaemia within stage 1 or 2 of the Bruce Protocol indicates a low threshold for ischaemia.
•
Other high-risk findings include a fall in blood pressure during exercise, widespread, marked or prolonged ischaemic ECG changes, and exercise-induced arrhythmia.