Holter Monitoring and Loop Recorders: From Research to Clinical Practice

Abstract

Since the 1960s, Holter monitoring has been a cornerstone for diagnosing suspected arrhythmias in patients of all ages. 1 The most common monitoring systems allow the continuous registration of three or more leads for 24-48 hours; newer Holter monitors allow continuous electrocardiogram (ECG) registration for 2 weeks.1 Extending the time of ECG registration will increase the diagnostic yield of Holter monitoring, especially for those rhythm disturbances that are infrequent but recurrent.1,2 This need for a prolonged ECG monitoring has been addressed by event recorders, which can monitor patients for up to 3 years, storing the ECG obtained a few minutes before and after the onset of an arrhythmia in its memory and transmitting data to the cardiac unit. 1,2 When interpreting the results of the ECG, the cardiologist has to determine whether symptoms reported by the patient could be linked to significant disturbances in heart rhythm.2 In other circumstances the detection of atrial or ventricular arrhythmias may alert the cardiologist, even if they occur asymptomatically, thus prompting a specific therapeutic decision such as starting antiarrhythmic or anticoagulant drugs or implanting a pacemaker or a cardioverter defibrillator. Cardiac Monitoring SystemsCardiac rhythm monitoring has an established diagnostic and prognostic role in different circumstances: syncope, palpitations and monitoring of patients with known or suspected episodes of atrial fibrillation (AF), e.g. those with stroke of uncertain aetiology (cryptogenic stroke).1-3 ECG monitoring may also play a role in identifying ventricular tachycardia (VT) in patients with recognised risk of sudden cardiac death. 4 As many devices with different characteristics are available, the choice of the most suitable monitoring system largely depends on the likelihood of detecting a significant correlation between symptoms and ECG findings. Holter MonitorsTraditional ambulatory Holter monitors are simple devices that usually have three leads and continuously register the ECG. They can be short-(24-48 hours) or long-duration (1-2 weeks) devices.1 Two-week Holter monitoring is preferred when diagnosing or excluding AF in cryptogenic stroke, but loop recorders and outpatient telemetry have even higher detection rates. Loop Recorders and Post-event RecordersNewer generation monitors are the so-called event recorders.According to their specific functions they can be divided into two categories: loop recorders, which include external loop recorders (ELRs) and implantable loop recorders (ILRs); and post-event recorders (non-looping recorders). 1 AbstractHolter monitors are tools of proven efficacy in diagnosing and monitoring cardiac arrhythmias. Despite the fact their use is widely prescribed by general practitioners, little is known about their evolving role in the management of patients with cryptogenic stroke, paroxysmal atrial fibrillation, unexplained recurrent syncope and risk stratification in implantable cardioverter defibrillator or pacemaker candidates. New Holt...

Clinical evaluation of a small implantable cardiac monitor with a long sensing vector

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Atrial fibrillation following heart transplantation: A systematic review and meta‐analysis of observational studies

“…Possible explanations for this heterogeneity include the differences in the methodology of diagnosis of AF, surgical approach, and patient characteristics in each study. Second, there have been significant advances in cardiac monitoring technology and electrophysiology studies (EKG, signal‐averaged EKG, Holter monitor) . It is possible that AF has been detected and diagnosed more frequently in the later studies, which may be influencing the findings of incidence trends of AF following heart transplantation.…”

Evaluation of new generation loop recorders placed during surgical ablation for atrial fibrillation

“…Given the LR is a subcutaneously implanted foreign body there is the potential for infectious and skin/soft tissue erosion. Recent studies have demonstrated rates of LR infection between 2% and 4% whereas one report of 65 patients observed a single device infection and one instance of localized cellulitis, with both patients requiring LR explant . In the Damiano study no infectious complications were reported; however, this study followed patients for only a 12‐month period .…”