Prospective Study of Holter Monitoring in Pediatric Patients at Sohag University Hospital

Background: To estimate the various indications, values and misuses of Holter monitoring in the diagnosis and management of pediatric patients. Methods: The study was a prospective observational study, carried out at Pediatric Arrhythmia Clinic and at PICU of Sohag University Hospital over two years from 09/2017 to 09/2019. It encountered 80 pediatric patients (34 fe-males), their age ranged from 29 days to 15 years with mean age of 6.18 years. All patients were subjected to echocardiography, 12 leads ECG and holter monitoring for 24 hours. Minimum, mean, maximum heart rate, rhythms and corrected QT were evaluated. Indications of Holter examination, its abnormalities were analyzed, also its positive diagnosis and management were defined. Results: Palpitations and syncopy were the main indications for holter examination 22 (27.50%) patients for each, abnormal examination in 17 (21.25%), chest pain in 13 patients (16.25%) and cardiomyopathy (7.5%) (one with Hypertrophic Cardiomyopathy and five with Dilated Cardiomyopathy). There were 50 (62.50%) patients had abnormalities in Holter recordings. The highest contribution to diagnosis was in cardiomyopathy (83.3%) where the most common abnormalities were ventricular tachycardia (50%) and ventricular premature beats in (33.3%). An abnormal ECG was significantly associated with a higher diagnostic yield (p = 0.0001). Conclusion: The most important indications for Holter monitoring include palpitations, syncope, abnormal physical exam findings, chest pain, and cardiomyopathy. Holter monitoring is an extremely important tool in the assessment of patients with dilated cardiomyopathy. HM detects serious arrhythmias to identify patients who are at increased risk for subsequent morbid events. The abnormal ECG findings were associated with having an abnormal Holter, therefore Holter monitoring can be used to help select which patients should get this screening tool especially in low budget programs countries.


Introduction
More than 4 decades of clinical experience have shown long-term ECG to be one of the most effective noninvasive clinical tools in the diagnosis and assessment of cardiac symptoms, prognostic assessment or risk stratification of various cardiac populations and in the evaluation of many cardiac therapeutic interventions. It remains an indispensable and highly refined tool for cardiac rhythm analysis and risk prediction [1].
The clinical utility of ambulatory ECG lies in its ability to examine continuously a patient over an extended period of time, permitting patient ambulatory activity and facilitating the diurnal electrocardiographic examination of a patient in a changing environmental milieu (both physical and psychological) [2].
However, the value of Holter monitoring in capturing brief symptomatic episodes of conduction system disorders is limited by the fact that they have to occur often enough to be captured during the 24-hour period of recording. Holter technology was proven to be a valuable adjunctive non-invasive diagnostic technology to record the ambulatory long term ECG [3].
Despite its vast application in adult patients, studies in the paediatric age group are limited. The present work aimed to study the various indications, values and misuses of Holter monitoring in the diagnosis and management of pediatric patients.
This study included 80 pediatric patients who were recruited from pediatric arrhythmia clinic and PICU at Sohag University Hospital. Their age ranged from 29 days to 15 years with mean age of 6.18 years.

Patients and Methods
The study was prospective observational study that carried out at Pediatric Arrhythmia Clinic and at PICU of Sohag University Hospital over two years from September2017 to September 2019. An informed oral and written consent was taken from the caregivers of children included in the study. The study approved by Ethical Scientific Committee at Sohag Faculty of Medicine for approval. Inclusion criteria: Any child undergoes Holter monitoring was included in the study.
The patients were referred for the following indications: 1) Screening for arrhythmias in patients with: syncope, palpitations, chest pain, WPW, and abnormality on examination (rapid, slow, irregular heart).
2) Follow up of patients with frequent ventricular ectopics (VE) and on antiarrhythmic therapy.
3) In children with complete heart block, a decision needs to be made about their need for pacing. A lot of indications for pacing as stated by the AHA can be deduced from 24 hour HM. These include the presence of long pauses, the minimum heart rate and the presence of non benign arrhythmias.

4)
Patients with cardiomyopathy (dilated, hypertrophic and restrictive). Methods: All patients in this study were subjected to the following: 1) Echocardiography: the following echocardiographic variables were recorded • Normal echocardiography.
• Picture of myocarditis: Echocardiography demonstrates four-chamber dilation with poor ventricular function and AV valve regurgitation. A pericardial effusion may be present.
2) 12 leads ECG: 12 leads ECG was done to all infants & children before having Holter monitoring using (FUKUDA DENSHI, CARDIMAX, model FCP-7101). 12 leads ECG Record analyzed using specific centile tables for normal values of ECG waves & intervals according to age [4].
3) Holter monitoring. Duration: 24 hours. Type of machine: Mortara 2016 american made H3+. Software: Mortara Company American made. Holter monitoring was applied to all children, minimum, mean, maximum heart rate, rhythms and corrected QT were evaluated.
Positive contribution of Holter was identified as: 1) Diagnosis: Establishing a new diagnosis/changing a current diagnosis/confirming a suspected diagnosis.
2) Management: Introducing new therapy/withdrawal of current therapy/change of current dosage of therapy.
Analysis: All Holter recorders were subsequently analyzed. This analysis system uses a feature extraction system to group individual QRS complexes based on their features and utilizes technician interaction in arrhythmia analysis aided by visual superimposition to correct for artefact and any erroneous analysis.
Arrhythmia detected either by ECG or Holter according to specific arrhythmia definitions as reported by George and his colleagues [5].
Statistical analysis Data was analyzed using STATA version 14.2 (Stata Statistical Software: Release 14.2 College Station, TX: StataCorp LP.). Quantitative data was represented as mean, standard deviation, median and range. Data was analyzed using student t-test to compare means of two groups and ANOVA for comparison of the means of three groups or more and least significance difference (LSD) post hoc test. When the data was not normally distributed Kruskal Wallis test for comparison of three or more groups and Mann-Whitney test was used to compare two groups.

Results
The median age of the 80 included patients (34 females and 46 males) was 6 years ranging from 29 days to 15    There were 22 patients with palpitation, the holter recording was normal in 11 patients, 4 patients had sinus tachycardia, 3 patients had ventricular ectopics, one patient had 2nd degree heart block, 2 patients had SVT and one patient had WPWS pattern.
There were 22 patients with Syncope, the holter recording was normal in 8 patients, one patient had sinus bradycardia, another one patient had sinus ta-chycardia, 2 patients had atrial ectopic, one patient had junctional ectopic, 5 patients had ventricular ectopics, 3 patients had 1 st degree heart block and one patient had ventricular tachycardia (diagnosed by stress ECG as catecholaminergic ventricular tachycardia).
There were 17 Patients with abnormal examination which include irregular HR (heart block & ectopics), tachycardia and bradycardia The holter recording was normal in 2 patients, 6 patients had sinus bradycardia, 3 patients had sinus tachycardia, one patient had junctional ectopic, one patient had ventricular ectopics, one patient had 1 st degree heart block, 2 patients had 3rd degree heart block and one patients had SVT.
There were 13 patients with chest pain, the holter recording was normal in 9 patients one patient had sinus tachycardia, one patient had junctional ectopic and 2 patients had ventricular ectopics.
There were 6 patients with cardiomyopathy (5 DCM & 1 Hypertrophic cardiomyopathy), all patients with cardiomyopathy had abnormal holter finding. Their Holter recording showed that one patient had sinus tachycardia, 2 patients had ventricular ectopics and 3 patients had ventricular tachycardia Table 4, Figure 1.  Of the 22 patients with palpitation holter was useful in diagnosis of 5 (22.73%) patients and was useful in management of 4 (18.18%) patients.
Of the 22 patients with syncope, Holter was useful in diagnosis of 10 (45.45%) patients and was useful in management of 7 (31.82%) patients.
Of the 17 patients with abnormal examination Holter was useful in diagnosis of 6 (35.29%) patients and was useful in management of 4 (23.53%) patients.
Of the 13 patients with chest pain Holter was useful in diagnosis of 4 (30.77%) patients and was useful in management of 2 (15.38%) patients.
Of the 6 patients with cardiompopathy ECG was useful in diagnosis of 5 (83.33%) patients and was useful in management of 2 (33.33%) patients Table 5, Figure 2.
Eighty-four% of patients who had abnormal ECG had abnormal Holter recording, with astatically significant difference between patients who had normal ECG and abnormal ECG regarding positive abnormality in Holter.
Holter recording was useful in diagnosis of 55% of patients with astatically World Journal of Cardiovascular Diseases

Discussion
The clinical utility of ambulatory ECG lies in its ability to examine continuously a patient over an extended period of time, permitting patient ambulatory activity and facilitating the diurnal electrocardiographic examination of a patient in a changing environmental milieu (both physical and psychological) [2]. Despite its vast application in adult patients, studies in the pediatric age group are limited. The present work aimed to study the various indications, values and misuses of Holter monitoring in the diagnosis and management of pediatric patients.
The present study conducted 80 pediatric patients who were recruited from Pediatric Arrhythmia Clinic and PICU at Sohag University Hospital their age range was 29 days to 15 years with mean age of 6.18 years. 46 (57.5%) males and 34 (42.5%) females. The main indications for Holter monitoring of these patients were palpitation & syncope. These results agree with findings of many literatures [6] [7]. The most common indication for Holter examination in our cohort patients was the evaluation of palpitaion. In this study there were 22 patients with palpitation, the Holter recording demonstrated abnormalities in 11 patients; four had sinus tachycardia, three had ventricular ectopic, one had 2nd degree heart block, two had SVT and one had WPWS pattern,, with a diagnostic yield of 22. The current study reported 22 patients with Syncope, their Holter recording was normal in 8 patients, one patient had sinus bradycardia, another one patient had sinus tachycardia, 2 patients had atrial ectopic, one patient had junctional ectopic, 5 patients had ventricular ectopic, 3 patients had 1 st degree heart block and one patient had ventricular tachycardia, with a diagnostic yield of 45.45% of patients and an percentage of 31.82% had a change of management. Cardiac arrhythmias should be considered among the malignant causes of syncope in children. Hence, syncope is a common cause of referral for Holter (27.5%, n = 22 patients) [8]. The low diagnostic yield of Holter in children with syncope had been previously reported [9].
The results of the present study agrees with that of Kilic, et al., who reported a much higher diagnostic yield of AECG, but the highly selective nature of the study population most likely contributed to this fact [10].
Chest pain is a common cause of anxiety among patients and parents and it is one of the most frequent causes of referral to cardiology outpatient clinics. Our results demonstrated 13 cases (16.25%) with chest pain, the Holter recording was abnormal only in 4 patients; one had sinus tachycardia, one had junctional ectopic and 2 had ventricular ectopic. It with a diagnostic yield of 30.77% of patients and a percentage of 15.38% had a change of management. This agrees with the findings of Baker, et al. and Hegazy, et al. who documented that chest pain particularly in the absence of organic heart disease, Holter monitoring has little value. The primary role of HM in this case may be to exclude rather than diagnose a cause [11]. Despite large pediatric study by Hegazy et al., demonstrated none of their patients presented with chest pain had abnormal recordings [7].
In the current study there were 6 patients with cardiomyopathy (five with Holter monitoring assessments to complete their diagnostic work up and help decision making [12].
Our results found only one patient had WPWS pattern, although the diagnostic assessment and the treatment have been described in patients with symptomatic WPW, the management of asymptomatic subjects remains controversial.
Holter monitoring was deemed unnecessary in evaluation of asymptomatic patients with WPW. Usually these patients are assumed to have a benign process, however very occasionally they present with VF as the first manifestation of the syndrome hence the dilemma of how extensively they should be investigated and managed. Despite the fact that Sarubbi, 2006 has been concluded that patients with WPW who develop AF and VF are different from those who don't; noninvasive methods as HM seem to be relatively incomplete for risk stratification [13].
The current study did not encountered children with postoperative arrhythmia due to our hospital had adult cardiac surgery only. Despite large study results by Hegazy et al., [7] revealed the value of HM in postoperative arrhythmia that reported 29.4% diagnostic yield and 26.5% in their management. However, their study established the HM is an important non-invasive method for detecting heart rhythm in children after repair of Fallot' tetrology.
The higher percentage of abnormal Holter findings in the present study compared to other studies is probably due to the highly selective nature of the study population. ECG examination is economical compared with the HM that is a major consideration in developing countries with low -budget programs. Thus, we aim to predetermine the usage and indications of HM based on the results of current study and the previous literatures.

Study limitations
Limitations of the present study include its single center experience and the relatively small number of patients. More studies with a larger number of children and follow up patients with postoperative and post device closure of ASD and VSD assessment is required.

Conclusion
The most important indications for Holter monitoring include palpitations, syncope, abnormal physical exam findings, chest pain, and cardiomyopathy. Holter monitoring is an extremely important tool in the assessment of patients with dilated cardiomyopathy. HM detects serious arrhythmias to identify patients who are at increased risks for subsequent morbid events. The abnormal ECG findings were associated with having an abnormal Holter, therefore Holter monitoring can be used to help select which patients should get this screening tool especially in low budget programs countries.