Empty
1. Knuuti J, Wijns W, Saraste A, Capodanno D, Barbato E, Funck-Brentano C, et al. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J. 2020;41(3):407-477.
PMID: 31504439
DOI: https://doi.org/10.1093/eurheartj/ehz425
2. Fihn SD, Gardin JM, Abrams J, Berra K, Blankenship JC, Dallas AP, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease. J Am Coll Cardiol. 2012;60(24):e44-e164.
PMID: 23182125
DOI: https://doi.org/10.1016/j.jacc.2012.07.013
3. Khan MA, Hashim MJ, Mustafa H, Baniyas MY, Al Suwaidi SKBM, AlKatheeri R, et al. Global epidemiology of ischemic heart disease: Results from the Global Burden of Disease Study. Cureus. 2020;12(7):e9349.
PMID: 32742886
DOI: 10.7759/cureus.9349
4. Ibanez B, James S, Agewall S, Antunes MJ, Bucciarelli-Ducci C, Bueno H, et al. 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J. 2018;39(2):119-177.
PMID: 28886621
DOI: https://doi.org/10.1093/eurheartj/ehx393
5. Amsterdam EA, Wenger NK, Brindis RG, Casey DE Jr, Ganiats TG, Holmes DR Jr, et al. 2014 AHA/ACC guideline for the management of patients with non–ST-elevation acute coronary syndromes. J Am Coll Cardiol. 2014;64(24):e139-e228.
PMID: 25260716
DOI: https://doi.org/10.1016/j.jacc.2014.09.017
Background
Cardiac event monitors are non-invasive, ambulatory electrocardiographic (ECG) devices used to continuously record the heart’s electrical activity for extended periods of time. The Holter monitor is the most common type, typically worn for 24–48 hours, providing continuous ECG monitoring to detect arrhythmias, ischemic changes, and conduction abnormalities not captured on standard resting ECG.
They are designed to correlate transient or intermittent cardiac symptoms (e.g., palpitations, syncope, chest pain) with underlying rhythm disturbances and to assess therapy efficacy.
Classification/Types
Holter Monitors
Continuous ECG recording for 24–72 hours.
Best for frequent daily symptoms.
Event Recorders
Activated by the patient during symptoms.
Worn for weeks to months; used when symptoms are infrequent.
Loop Recorders
Continuously record and overwrite memory until activated.
Capture events before and after activation.
Patch Monitors
Adhesive patch devices (e.g., Zio Patch).
Provide up to 14 days of continuous monitoring with improved patient compliance.
Implantable Loop Recorders (ILRs)
Subcutaneous devices lasting up to 3 years.
Used for unexplained syncope or cryptogenic stroke evaluation.
Pathophysiology and Rationale
Transient cardiac arrhythmias may go undetected on a 12-lead ECG due to their sporadic nature. Holter and event monitors extend the monitoring period, increasing the likelihood of correlating symptoms with arrhythmic episodes. They provide real-world cardiac rhythm data during daily activities, exercise, and sleep.
Indications
- Evaluation of palpitations or suspected arrhythmia.
- Assessment of syncope or presyncope.
- Monitoring efficacy of antiarrhythmic therapy or pacemaker/ICD function.
- Detecting silent myocardial ischemia.
- Risk stratification in patients with cardiomyopathy or prior myocardial infarction.
- Post-ablation or post-cardiac intervention follow-up.
Contraindications
- Severe dermatologic conditions preventing electrode/patch placement.
- Patient non-compliance or inability to maintain device.
- Rarely, allergic reactions to adhesives.
Diagnostic Yield
- Holter monitors: High yield for daily arrhythmias (atrial fibrillation, PVCs, ventricular tachycardia).
- Event monitors/loop recorders: Higher diagnostic yield in patients with infrequent symptoms.
- Patch monitors: Greater patient adherence and longer continuous monitoring increase arrhythmia detection rates.
Procedure and Use
Preparation: Clean skin, apply electrodes or patch.
Recording: Continuous or patient-activated data collection.
Diary: Patients log symptoms, activities, and timing for correlation.
Analysis: ECG data reviewed for arrhythmias, pauses, ischemic changes.
Physical Exam Findings Correlated
Vital Signs
- Tachycardia or bradycardia at rest or during symptomatic episodes.
General Appearance
- Syncope, dizziness, or paleness during arrhythmic events.
Cardiovascular System
- Irregular pulse, dropped beats, rapid or slow heart rate.
- Correlation with auscultatory findings (e.g., irregularly irregular rhythm in atrial fibrillation).
Neurological System
- Syncope, presyncope, confusion, or seizure-like activity associated with transient arrhythmias.
Advantages
- Non-invasive, ambulatory, real-time correlation of symptoms and rhythm.
- High diagnostic yield compared to standard ECG.
- Cost-effective compared to more invasive investigations.
Limitations
- Holter monitors: Limited recording period, may miss infrequent arrhythmias.
- Patient discomfort or non-compliance.
- Artifact and electrode dislodgement may compromise recording quality.
- Requires patient cooperation for accurate symptom diaries.
Complications
- Minor skin irritation from electrodes or patches.
- Data loss due to technical malfunction.
- False positives from artifacts.
Follow-up and Clinical Decision-Making
- Results guide therapy decisions such as initiation of antiarrhythmic drugs, anticoagulation for atrial fibrillation, pacemaker/ICD placement, or electrophysiology referral.
- Patients with negative Holter but ongoing symptoms may require extended monitoring with event recorders or implantable loop recorders.
