24hr Holter monitoring

Last updated date: 30-Jan-2023

Originally Written in English

24hr Holter Monitoring

Palpitation is among the most prevalent problems noticed by primary care doctors and cardiologists when they consult outpatients. Although it is normally harmless, it can occasionally be a sign of life-threatening diseases. Because historical clues are not always reliable, determining the source of palpitations can be challenging.  The majority of patients with arrhythmias do not experience palpitations. Palpitations are often caused by any type of arrhythmia, including sinus tachycardia, atrial fibrillation, premature ventricular contractions, or ventricular tachycardia.

The Holter analysis is recommended by the American College of Cardiology and the American Heart Association for individuals who have unexplainable fainting, near syncope, palpitations, or dizziness as class I indications for symptomatic assessment. If the causative disease of the palpitations cannot be diagnosed from the patient's history, physical assessment, and ECG, Holter monitoring is usually recommended, but the yield of this instrument is low in individuals whose symptoms occur occasionally.


Holter Monitoring

Holter Monitoring

Over the last five decades, Holter monitor has become more popular for diagnosing cardiac arrhythmias. It was created with the intention of observing deviations in normal heart rhythm during daily activities. Its application has expanded over time to include the detection of cardiac arrhythmias, assessment of arrhythmias, assessment of pharmacologic therapy, detection of pacemaker problems, heart rate variability investigations, and arrhythmia prognostic classification. It's also been used to diagnose atypical symptoms including palpitations, drowsiness, forgetfulness, drop episodes, and atypical chest pain, as well as to identify silent events of myocardial ischemia. Holter monitoring is a frequent diagnostic tool for evaluating these complaints.


What is Holter Monitoring?

What is Holter Monitoring?

A Holter monitor is battery-operated medical equipment that monitors the activity of the heart, such as pulse rate and rhythm. If the doctors need more data about how the heart works than a conventional electrocardiogram (ECG) can provide, they may request you to have one.

Holter monitoring for 24 hours is a continuous study that records the heart's rate and rhythm. The Holter monitor is worn for 24 hours while you go on your usual activities. This device has the same electrodes and electrical leads as a standard ECG, but with fewer leads. It can detect not just your heart's rate and rhythm, but also when you experience chest discomfort or manifestations of an irregular heartbeat (arrhythmia).

Ambulatory electrocardiogram (ECG) is another name for the Holter monitoring test. Other devices that can be used to assess cardiac rhythm for extended periods of time are available.


Indications of Holter Monitoring

Indications of Holter Monitoring

In the literature, there are no applicable suggestions for identifying patients who might benefit from Holter monitoring. The following are the current proposals:

  • Palpitations and irregular heartbeats were studied to see whether there was a link between the two.
  • To figure out what's causing the syncope or near-syncope.
  • To determine the severity of sudden cardiac arrhythmias or myocardial ischemia.
  • When brief atrial fibrillation or flutter is suspected, patients with neurologic episodes should be evaluated.
  • To make note of the efficacy and side effects of pharmacological and nonpharmacological interventions.
  • To identify proarrhythmic responses to antiarrhythmic medication.

The choice between two to three lead Holter monitoring and 12 lead Holter monitoring is largely determined by the preferred result. two to three leads are acceptable if it is being used to assess heart rate and rhythm. A 12 lead Holter monitoring, on the other hand, is the preferred modality for determining the cause of premature beats, dysrhythmias, or tachycardia.

The type of monitor to employ is determined by the frequency of episodes. A standard twelve-lead electrocardiogram is sufficient to determine a diagnosis when symptoms are persistent. For intermittent symptoms, cardiologists usually employ the Holter monitor. If symptoms only occur infrequently, longer-term devices such as an implantable loop recorder or an event monitor can be employed.

Supraventricular tachycardia (SVT), ventricular tachycardia (VT), atrial flutter, atrial fibrillation (AF), monomorphic or polymorphic VTs, long QT syndromes, supraventricular premature complexes (PAC), ventricular premature complexes (PVC), dominant atrioventricular accessory pathways, atrioventricular block, right and left bundle branch block, and left anterior and posterior fascicular block can all be diagnosed with a 12-lead Holter monitor.


Contraindications of Holter Monitoring

Contraindications of Holter Monitoring

  • If it delays urgent intervention, hospital admission, or a procedure, Holter monitoring is not recommended. It should not, for example, be included in the initial evaluation of angina, when a stress ECG test is more suitable.
  • The monitor is also not recommended in patients who have syncope and other high-risk conditions, as inpatient care is required at that time.
  • Patients experiencing symptoms including syncope, near-syncope, recurrent dizziness, or palpitation who have no other obvious reasons based on history, physical examination, or laboratory findings.
  • Even if patients had cardiovascular diseases such as left ventricular hypertrophy or valvular heart disease, the ACC recommendations opposed the use of ambulatory ECG for arrhythmia diagnosis or measurement of heart rhythm variation for risk assessment in patients without complaints of arrhythmia.



An amplifier, tape recorder, electrodes attached to the individual's chest, playback unit, and analyzing unit made up the first Holter monitor, which was about the size of a briefcase. It was made up of ten electrodes, comprising six normal precordial electrodes and four torso electrodes. The purpose of chest leads is to keep signals from getting messed up. The chest leads, on the other hand, can vary. Mathematical strategies were offered to address these variations. While early versions had 12 leads, more current models have had as few as two or three leads.

The Holter is now the size of a small cell phone and provides two types of primary data to evaluate. The QRS complex is the one, and the R-R interval is another. It records constantly till it is disconnected from the person or the battery expires, however it is often used for 24-48 hours. 


Technique of Holter Monitoring

For 12–48 hours, Holter monitoring records an electrocardiogram (ECG) tracing on three channels. To match the timing of symptoms with the ECG, the patient presses a button. A qualified physician and a cardiac technologist evaluate the full recorded ECG for anomalies.

The usage of a Holter monitor in kids is limited due to wires and connections. The FDA approved a tool that is wireless, water-proof, and capable of continuous single-channel heartbeat monitoring for up to two weeks. Patients can start the recording by clicking a button to induce symptoms and link symptoms with the rhythm.


Holter Monitor Wireless

Holter Monitor Wireless

The system is a wireless patch with a low-cost disposable element and a battery-powered electronic device that measures 65 over 125 mm. The patch measures heart rate, heart rate variability, and arrhythmias while recording a single-lead ECG. The information is sent over Bluetooth to a mobile phone or a computer. The gadget, which is positioned on the upper left quarter of the patient's chest, also stores the collected impulses and information. On a single battery charge, the patch-based gadget provides up to seven days of tracking and storage and four days of real-time interaction with the web through a smartphone. The process of receiving, storing, and analyzing a wide range of impulses opens up the possibility of going much beyond simple parameter monitoring. The system sends an alarm to the computer whenever the patient's vital signs reach a hazardous level, and the doctor can see real-time data and ECG readings. The device also has a record event key, which patients are urged to press in the occurrence of symptoms.

The device was triggered via the Smart-Cardia smartphone app using Bluetooth communication after the coordinator/nurse applied the patch to the patient's chest. When the gadget was turned on, the real-time Electrocardiogram of the patient appeared on the screen, and the data recording began. After at least one day of recording, the device is withdrawn, the wireless disposable patch and electronic component are detached, the patch is discarded, and the data were uploaded to a computer via USB connection for processing, quality management, and report production.

The patch's ECG-based arrhythmia episodes were compared to a reference method with other Holter. Two distinct US board-certified cardiac technologists monitored and evaluated the Holter and patch information in a blinded manner, using the Holter and patch programs, respectively. An electrophysiologist double-checked the recorded arrhythmia episodes from both systems. The line drawings were carefully evaluated by the investigators if there were differences between the two device reports for the same patient. Components of the ECG waveform that were not assessable by the technologists, such as motion artifacts or muscle activity in the ECG data, were categorized as noise.

The existence of any arrhythmia or conduction irregularities on the patient's tracings was enough to rule out an arrhythmia or conduction abnormality.


What should I expect with the Holter Monitor?

  • The Holter monitor will be attached by a properly qualified technician who will show you how to record your symptoms while using it.
  • The electrodes are first attached to your chest by the technician. He or she may remove some hair off your chest if you have chest hair in order to secure the electrodes.
  • After the electrodes are in place, the technician assists you in putting on the Holter monitor and instructs you on how to care for it.
  • The monitor can be carried in a pocket or bag, or draped across your shoulders and neck like a handbag or camera. It can even be attached to your waist.
  • With the following exceptions, go about your normal activities while wearing the monitor:
  1. While wearing the monitor, do not bathe, shower, or swim.
  2. While wearing the monitor, avoid having X-rays.
  3. High-voltage places, detection systems, and large magnets should all be avoided.


  • During the test, the expert will explain to you how to keep a record of your movements and symptoms. It's critical to keep a detailed diary. If you experience symptoms like chest pain, difficulty breathing, irregular heartbeats, or fainting, keep track of when they started and what you were doing in your notebook. The variations in your ECG captured by the Holter monitor will be compared to the entries in your diary.


Cardiac Arrhythmia Discovered by Holter Monitor

Cardiac Arrhythmia by Holter Monitor

Supraventricular Tachycardia

Supraventricular tachycardia is a rapid or irregular heartbeat that involves the upper chambers of the heart. Cardiac arrhythmia is used as the medical term for an irregular heartbeat. Paroxysmal supraventricular tachycardia is synonymous with supraventricular tachycardia.

A healthy heart rate ranges between 60 and 100 beats per minute. Tachycardia is defined as a pulse rate of greater than 100 beats per minute. Your heart is beating roughly 150 to 220 times per minute during an attack of supraventricular tachycardia, but it can rarely beat faster or slower.

The majority of people with supraventricular tachycardia lead normal lives free of limitations or therapy. Others may require lifestyle modifications, medications, or heart surgeries to reduce or eradicate their rapid heart rhythm and symptoms.


Atrial Fibrillation

The most frequent type of treated heart arrhythmia is atrial fibrillation, also known as AFib or AF. When the heart beats too slowly, too quickly, or irregularly, it is called an arrhythmia.

When a person has atrial fibrillation, the usual pacing in the higher chambers of the heart (the two atria) is irregular, and blood flow from the atria to the lower chambers of the heart (the two ventricles) isn't as efficient as it should be. Atrial fibrillation can manifest itself as a series of transient bouts or as a long-term disease.


Atrial Flutter

One of the most prevalent aberrant cardiac rhythms is atrial flutter. It's triggered by an aberrant electrical circuit in the heart's upper chambers, which causes the atria to flutter and pulse fast rather than fully contracting. It can cause rapid heart rhythms and a heart that isn't as efficient as it should be. This raises your chances of having a stroke and may make you feel unwell.

Electrical impulses are given out from the right atriums' sinus node in a healthy heart. The pulse rate and the rhythm of heartbeats are controlled by this node. The atria are where electric signals flow through the cardiac muscle. This causes the muscle to contract. An aberrant electrical circuit emerges in the atria during atrial flutter. The upper chambers contract abnormally rapidly as a result of this.


Sinus Pause

The brief stoppage of sinus node firing is known as sinus pause or arrest. During sinus pause, there are no P waves or concomitant QRS-T on an electrocardiogram. This pause is sometimes followed by a junctional beat or idioventricular rhythm. Asystole occurs when the escape rhythm is absent. Sinus pauses of less than 3 seconds normally do not require further evaluation and can be observed in healthy people; however, lengthier pauses (more than 3 seconds) necessitate additional evaluation and treatment.


Ventricular Arrhythmia

Ventricular arrhythmia is a heart rhythm abnormality caused by aberrant electrical impulses in the heart's lower chambers. Ventricular tachycardia is another name for this disease.

At rest, a normal heart beats roughly 60 to 100 times per minute. The heart beats faster than normal in ventricular tachycardia, usually 100 or more times/minute.

The irregular heart rates impede the heart chambers from filling with blood appropriately. The heart may be unable to deliver enough blood to the body and lungs as a consequence.

Ventricular tachycardia can last anywhere from a few seconds to several minutes. You may have dizziness, difficulty breathing, or chest pain. Ventricular tachycardia can sometimes end up causing the heart to stop beating (sudden cardiac arrest), which is a serious medical emergency.


Complications of Holter Monitoring

The device is kept in an external pocket near the patient's chest, commonly in the form of a neck sling or in the patient's vest pocket. So, there aren't any dangers in theory, but the surface electrodes can irritate the underlying skin and cause skin ulceration if left in place, although this infrequently happens because the device specialists remove them when they remove the device from the patient.


Acute Myocardial Infarction ECG

For the diagnosis of the acute coronary syndrome, the resting 12-lead ECG is the first-line diagnostic technique. Within 10 minutes of the patient's arrival at the emergency room, it should be obtained. Dynamic alterations in the ECG waveform are frequently related to acute MI. If the initial EKG is non-diagnostic at presentation, serial ECG monitoring can provide vital clues to the diagnosis. The extent of reperfusion or re-occlusion can be determined using serial or continuous ECG monitoring. Reperfusion usually results in a significant and rapid decrease in ST-segment elevation.


ECG Changes of Acute Myocardial Infarction

In the absence of left ventricular hypertrophy and bundle branch block, the following ECG abnormalities suggest persistent coronary artery occlusion:

  • ST-segment elevation in two contiguous leads of greater than 5 mm in men younger than 40 years, greater than 2 mm in men older than 40 years, or greater than 1.5 mm in women in leads V2-V3 and/or greater than 1 mm in all other leads
  • New horizontal or down-sloping ST-segment depression greater than 5 mm in two consecutive leads and/or T inversion greater than 1 mm in two consecutive leads with significant R waves or R/S ratio greater than 1 mm
  • Hyperacute T-wave amplitude, with significant symmetrical T waves in two consecutive leads, could be an early indicator of acute MI, which could occur before ST-segment elevation.
  • Cardiac arrhythmias, intraventricular blocks, atrioventricular conduction delays, and loss of precordial R-wave amplitude are all ECG abnormalities linked to myocardial ischemia.


ECG Changes of Previous Myocardial Infarction

  • Any Q wave greater than 0.02 s in lead V2-V3 or QS complex greater than 1 mm deep in lead V2-V3  
  • Any Q wave greater than 0.02 s in lead V2-V3 or QS complex greater than 1 mm deep in lead V2-V3  
  • In the absence of a conduction defect, R wave > 0.04 s in V1-V2 and R/S more than 1 with a concordant positive T wave.



Holter Monitor

Holter monitoring had good diagnostic accuracy in identifying significant cardiac arrhythmias or patient symptomatic episodes, but as opposed to a shorter 24 hr. monitoring period, a duration of 48 hr. monitoring proved to be of modest additional benefit.