Arrhythmic indications for ambulatory ECG monitoringCardiac palpitations
Сardiac palpitations have an infrequent nature. And so, sometimes, medium-term monitoring is indicated. An implantable device may one day become a perfect solution for the diagnosis of palpitations, but it is not established yet. And so this is the most prevalent indication for ambulatory ECG monitoring. Holter monitor is the most common technique used right now. A negative test in the presence of symptoms is often diagnostic and therapeutic.
Unexplained syncope or dizziness
If the patient has frequent symptoms, such as daily dizziness, Holter monitoring is very useful. Convenience and wide availability of the Holter monitoring make it a basic solution for the initial investigation in patients even with relatively infrequent episodes. But the success of Holter monitoring is limited in cases when the symptoms do not occur during the study. And so, medium-term automatic and long-term implantable loop recorders are crucial investigative tools for patients with syncope.
Suspected slow heart rhythms
In this case, a Holter monitor is preferable to all other methods because it provides a 24-hour or longer monitoring of the heart rate changes and can be synchronized with symptoms. This study should be done occasionally and at infrequent intervals depending on the symptoms. Holter monitoring is a critical investigation for such patient groups as the ones assessed for pacemaker implantation or requiring implantable cardioverter defibrillators.
Hereditary “electrical” abnormalities
This diverse group involves cardiac arrhythmias-associated hereditary abnormalities associated. The most common among them is the Wolff-Parkinson White syndrome with an accessory pathway, ventricular pre-excitation, and atrioventricular re-entrant tachycardia. This can lead to a sudden death caused by conduction of atrial fibrillation through the accessory pathway leading to a very rapid ventricular response and subsequent ventricular fibrillation. Ambulatory ECG monitoring can be performed to detect the re-entry tachycardia or even atrial fibrillation. But the probability of recording these arrhythmias depends on the frequency of patient symptoms, and so it is extremely unlikely for many patients.
Evaluate the abnormal ECG; ectopy and heart block
This is a very specific group, because frequent ventricular ectopy may require electrophysiologic ablative therapy. And the monitoring of the frequency of ectopic activity with the ablative therapy or pharmacological intervention requires repeated Holter monitoring. Evaluation for paroxysmal AFib requiring oral anticoagulation for frequent supraventricular ectopy patients, bundle branch block, bifascicular block, or atrioventricular block may also be done with Holter monitoring.
Cryptogenic Stroke Evaluation ‘‘Neuro-cardiology”
The most likely diagnosis in patients with a cerebrovascular accident of no known cause is occult asymptomatic atrial fibrillation or flutter. Holter monitoring is considered to be a preferable solution after an unhelpful ECG. Patient-activated event recording is of little use in this case due to the asymptomatic nature of the condition. In general, the length of the monitoring is considered to be one of the main factors for increasing the likeability of atrial fibrillation detection.
Evaluation of the success of either antiarrhythmic or ablative therapy
Ambulatory ECG may be desirable for quantitative and correlative assessment of symptoms and ECG findings for ventricular ectopic activity and ventricular arrhythmias. Also, it is considered to be a standard option for the assessment of supraventricular and ventricular arrhythmia patients who have undergone ablative therapy. Another indication is the monitoring of pro-arrhythmic responses after initiation of antiarrhythmic agents in high-risk patients.
Evaluation of ventricular tachycardia
Ambulatory ECG monitoring is used for the evaluation of ventricular arrhythmias and in particular assessment of the success after the therapeutic or ablative interventions. The Holter is the main solution for this scenario, but medium and long-term monitoring also has a growing role. In some rare situations, ambulatory ECG monitoring is necessary to exclude intermittent ventricular tachycardia - myocardial contusion or foreign body irritation such as the presence of prosthetic heart valves and functioning or redundant implanted pacemaker and cardioverter defibrillator leads.
Following acute myocardial infarction
Ambulatory ECG monitoring is often performed to detect cardiac arrhythmias in the recovery phase following an acute myocardial infarction. Arrhythmias, including atrial fibrillation, ventricular ectopy, tachyarrhythmias, and combinations of atrioventricular block and bradycardia are usually documented during the early phase. Monitoring review is necessary to guide therapeutic intervention and risk stratification.
Congestive and hypertrophic cardiomyopathy
Such patients are prone to ventricular and supraventricular tachyarrhythmias. Studies are recommending oral anticoagulants for AFib and implantable cardioverter defibrillators for potentially lethal ventricular tachyarrhythmias. And so the use of ambulatory ECG monitoring has become routine. Despite being useful, Holter monitoring has a low yield unless the patient is experiencing frequent palpitations. Event monitors may be very important for such a case as are implantable loop recorders for patients experiencing unexplained syncope.
Monitor cardiac implantable electronic device therapy
Cardiac implanted electronic devices (CIEDs), like pacemakers and implantable cardioverter-defibrillators, are sophisticated devices that deliver electrical therapy to the heart. This therapy may differ, with high voltage for defibrillation, low voltage for slow heart rhythms, and biventricular pacing for cardiac resynchronization therapy. Holter monitoring is valuable for evaluating cardiac resynchronization therapy. For therapy to be effective, patients need to be paced in both ventricles at least 90% of the time. The implanted device counts the number of sensed beats, but the requesting physician may still be concerned that the paced beats are ineffective for ventricular resynchronization because of intermittent ventricular fusion, This should be recognized in the Holter monitor tracings.
Dr. Nadezhda Klyzhanovska, MD, PhD