Is atrial septal defect alone able to affect the cardiac autonomic function or are there different factors that influence this function?/Author's Reply

To the Editor,

We read with a great interest the paper by Özyilmaz et al. (1) entitled "Heart rate variability improvement in children using transcatheter atrial septal defect closure" published in the Anatol J Cardiol 2015 Mar 4. The authors aimed to evaluate cardiac autonomic functions in children who underwent transcatheter closure of atrial septal defect (ASD) using analysis of heart rate variability (HRV) parameters. They concluded recovery of HRV indices approximately 6 months after transcatheter ASD closure.

ASD is a frequently seen congenital heart disease characterized with left-to-right shunting and dilation of the right cardiac chambers and pulmonary artery, which might result in heart failure, arrhythmia, and thromboembolic events as well as increased mortality. The enlarged right ventricle usually returns to normal size during the first 24 months after transcatheter device closure or surgical repair, although this normalization may persist for up to 5 years after defect closure (2). As mentioned in the article by Özyilmaz et al. (1), HRV impairment in patients with ASD has been attributed to right ventricular filling and right atrial tension due to left-to-right blood flow through ASD (3). However, in the study by Özyilmaz et al. (1), no data demonstrating dimensions of cardiac chambers before and after the transcatheter closure are available, and we do not know whether the initial dimensions are significantly different from those measured 6 months after transcatheter closure. In addition, the mean diameter of ASD as well as the range of the diameter of the defect in the study population is not mentioned in the article. With these additional data, we believe that readers of the journal can more easily understand whether the size of the defect and the dimensions of cardiac chambers have an effect on HRV parameters.

The interpretation of HRV analysis is not as simple as thought because of various factors that influence HRV indices, which might be affected by many variables such as hyperlipidemia and blood pressure (3-5). We think that it would be more helpful to demonstrate blood pressure levels and blood lipid profiles of the study population in terms of showing no variable affecting HRV parameters rather than ASD. Thus, one can understand whether ASD alone really impairs the cardiac autonomic function, which has a prognostic importance for survival (5).

References

1. Özyilmaz I, Ergül Y, Tola HT, Saygi M, Öztürk E, Tanidir IC, et al. Heart rate variability improvement in children using transcatheter atrial septal defect closure. Anatol J Cardiol 2015 Mar 4. Epub ahead of print.

2. Cansel M, Yagmur J, Ermis N, Açikgöz N, Tasolar H, Atas H, et al. Effects of transcatheter closure of atrial septal defects on heart rate variability. J Int Med Res 2011; 39: 654-61. [CrossRef]

3. Bakari S, Koca B, Öztunç F, Abuhandan M. Heart rate variability in patients with atrial septal defect and healthy children. J Cardiol 2013; 61: 436-9. [CrossRef]

4. Gülgün M, Fidanci MK. Heart rate variability can be affected by gender, blood pressure, and insulin resistance. Anatol J Cardiol 2015; 15: 262-3. [CrossRef]

5. Kudaiberdieva G, Görenek B, Timuralp B. Heart rate variability as a predictor of sudden cardiac death. Anatol J Cardiol 2007; 7: 68-70.

Mustafa Gülgün, Muzaffer Kürsat Fidanci, Alparslan Genç

Department of Pediatrics, Division of Pediatric Cardiology, Gülhane Military Medical Academy; Ankara-Turkey

Address for Correspondence: Dr. Mustafa Gülgün,

Gülhane Askeri Tip Akademisi, Pediyatrik Kardiyoloji Bölümü,

06010 Etlik, Ankara-Türkiye

Phone: [phone]

E-mail: [email protected], [email protected]

©Copyright 2015 by Turkish Society of Cardiology - Available online at www.anatoljcardiol.com

DOI:10.5152/AnatolJCardiol.2015.6595

Author's Reply

To the Editor,

We would like to thank the authors of the letter for their interest and criticism on our study entitled "Heart rate variability improvement in children using transcatheter atrial septal defect closure "published in Anatol J Cardiol 2015 Mar 4 (1).

Heart rate variability is a parameter used for the non-invasive evaluation of the neurohumoral control of the heart. One study reported reduced measurements of HRV in children with various congenital heart diseases (2). In another study, it has been shown that the dilatation of RV can decrease for up to 5 years after ASD closure (3). Some studies have published the normalization of RV size during the first 24 months after device closure (4). There may be other factors that affect the cardiac autonomic function besides atrial septal defect as the author mentions. However, Cansel et al. (4) found that the right ventricular diameter and pulmonary artery systolic pressure significantly decreased 6 months after transcatheter closure compared with values measured before transcatheter closure in patients with ASD. In our study, we concluded that HRV in children recovers approximately 6 months after transcatheter ASD closure. We did not report the dimensions of cardiac chambers before and after transcatheter closure. In our article, HRV after transcatheter ASD closure was compared with that of the control group. We did not declare that heart chambers reached normal values in 6 months. In our study, the 6th month HRV of patients who underwent transcatheter ASD closure approached the levels of the control group (1). HRV and reaching normal levels of right ventricular measurements are two different things. HRV could return to the normal range before the normalization of heart cavity due to hemodynamic improvement after transcatheter closure.

Our study was designed using the heart rate variability data of Holter ECG in the previously published "'Holter Electrocardiographic Findings and P-wave Dispersion in Pediatric Patients with Transcatheter Closure of Atrial Septal Defects"' study. A previously published part of this study was not used the heart rate variability data (5). Patient information [mean±SD, pulmonary artery pressure (mm Hg), Qp/Qs ratio, stretched diameter of ASD (mm), device defect ratio, device diameter (mm): 20.8±4.4, 2.1±0.4, 16.8±3.8, 1.3±1.4, 19±4.2, respectively] were not written again because they were declared in this previously published study (1).

References

1. Özyilmaz I, Ergül Y, Tola HT, Saygi M, Öztürk E, Tanidir IC, et al. Heart rate variability improvement in children using transcatheter atrial septal defect closure. Anatol J Cardiol 2015 Mar 4. Epub ahead of print.

2. Massin M, von Bernuth G. Clinical and haemodynamic correlates of heart rate variability in children with congenital heart disease Eur J Pediatr 1998; 157: 967-71. [CrossRef]

3. Meyer RA, Korfhagen JC, Covitz W, Kaplan S. Long-term follow-up study after closure of secundum atrial septal defect in children: an echocardiographic study. Am J Cardiol 1982; 50: 143-8. [CrossRef]

4. Cansel M, Yagmur J, Ermis N, Açikgöz N, Tasolar H, Atas H, et al. Effects of transcatheter closure of atrial septal defects on heart rate variability. J Int Med Res 2011; 39: 654-61. [CrossRef]

5. Özyilmaz I, Özyilmaz S, Tola HT, Saygi M, Kiplapinar N, Tanidir C, et al. Holter electrocardiography findings and P-wave dispersion in pediatric patients with transcatheter closure of atrial septal defects. Ann Noninvasive Electrocardiol 2014; 19: 174-81. [CrossRef]

Isa Özyilmaz, Sinem Özyilmaz*, Yakup Ergül, Alper Güzeltas

Departments of Pediatric Cardiology, *Cardiology, Mehmet Akif Ersoy Cardiovascular and Thoracic Surgery Center, Training and Research Hospital; Istanbul-Turkey

Address for Correspondence: Dr. Isa Özyilmaz,

Istanbul Mehmet Akif Ersoy Gögüs Kalp ve Damar Egitim ve

Arastirma Hastanesi, Istasyon Mah. Turgut Özal

Bulvari No:11, 34303 Küçükçekmece, Istanbul-Türkiye

Phone: + 90 212 692 20 00

Fax: + 90 212 471 94 94

E-mail: [email protected]