Arq Bras CardiolabcArquivos Brasileiros de CardiologiaArq. Bras. Cardiol.0066-782X1678-4170Sociedade Brasileira de Cardiologia - SBCtQdb6CVg9pP4xLG5cvGBt3tS0066-782X201600060054610.5935/abc.20160085Letter to the EditorPredictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid PatientsCeritLeventNear East University HospitalDepartment of CardiologyNicosiaCyprusDepartment of Cardiology - Near East University Hospital, Nicosia, CyprusMailing Address: Levent Cerit, The Institute of Environmental Sciences, Bogazici University, Turkey. Near East University Hospital, Near East Street. Postal Code 07100, Nicosia. E-mail: drcerit@hotmail.com, drcerit@yahoo.com0620161066546547250220162902201604032016This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Keywords:Atrial FibrillationHyperthyroidismEuthyroid Sick SyndromesThyroid Disease
To the Editor,
I have read with great interest the article entitled "Predictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid Patients" by Gürdogan et al.,1 recently published in Arquivos Brasileiros de Cardiologia. The investigators reported that rates of atrial fibrillation (AF) recurrence were similar in hyperthyroid and euthyroid patients and that the duration of AF was the only predictor of AF recurrence in both.
Hyperthyroidism is a well-known risk factor for paroxysmal and permanent AF. Marrakchi et al.2 have reported that a low serum thyroid-stimulating hormone (TSH) level is an independent risk factor for AF. All other factors predisposing to AF were mentioned and discussed in that article.
Additionally, Demir et al.3 have found a strong relationship between vitamin D deficiency and nonvalvular AF. Serum vitamin D levels correlated with high sensitive C-reactive protein levels and left atrial diameter, and were significantly associated with AF in Chinese patients with nonvalvular persistent AF.4 Hanafy et al.5 have revealed the direct electromechanical effects of vitamin D administration on the left atrium and found that vitamin D could effectively prevent and terminate AF.
In the light of this knowledge, Gürdogan et al.1 should have reported the vitamin D levels of the patients in their study and discussed the association between the levels of this vitamin and AF recurrence.
References1 Gürdogan M, Ari H, Tenekecioglu E, Ari S, Bozat T, Koca V, et al. Predictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patients. Arq Bras Cardiol. 2016;106(2):84-91.GürdoganMAriHTenekeciogluEAriSBozatTKocaVPredictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patientsArq Bras Cardiol2016106284912 Marrakchi S, Kanoun F, Idriss S, Kammoun I, Kachboura S. Arrhythmia and thyroid dysfunction. Herz. 2015;40(Suppl 2):101-9.MarrakchiSKanounFIdrissSKammounIKachbouraSArrhythmia and thyroid dysfunctionHerz201540Suppl 21011093 Demir M, Uyan U, Melek M. The effects of vitamin D deficiency on atrial fibrillation. Clin Appl Thromb Hemost. 2014:20(1):98-103.DemirMUyanUMelekMThe effects of vitamin D deficiency on atrial fibrillationClin Appl Thromb Hemost2014201981034 Chen WR, Liu ZY, Shi Y, Yin W, Wang H, Sha Y, et al. Relation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patients. Ann Noninvasive Electrocardiol; 2014:19(2):166-73.ChenWRLiuZYShiYYinWWangHShaYRelation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patientsAnn Noninvasive Electrocardiol20141921661735 Hanafy DA, Chang SL, Lu YY, Chen YC, Kao YH, Huang JH, et al. Electromechanical effects of 1,25-dihydroxyvitamin D with antiatrial fibrillation activities. J Cardiovasc Electrophysiol. 2014:25(3):317-23.HanafyDAChangSLLuYYChenYCKaoYHHuangJHElectromechanical effects of 1,25-dihydroxyvitamin D with antiatrial fibrillation activitiesJ Cardiovasc Electrophysiol2014253317323ReplyARIHasanDr.
We are pleased that Dr. Cerit showed great interest in our article entitled ''Predictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid Patients'' published in Arquivos Brasileiros de Cardiologia.1
Recent studies have found that vitamin D deficiency is related to nonvalvular AF.2,3 However, the relationship between this deficiency and nonvalvular AF is not dependent on the occurrence of thyroid disorder. In the study published by Demir et al.,2 the TSH levels were normal in all AF groups. In addition, thyroid dysfunction was an exclusion criterion in the studies by both Demir et al.2 and Chen et al.3 We did not evaluate the vitamin D levels in our study's participants, which we can add as a limitation of our research. However, the participants in our study did not report any symptom or treatment of vitamin D deficiency. After thyroid surgery, in particular, patients may have vitamin D deficiency and hypothyroidism, but none of the patients in our study had prior thyroid surgery.
Considering the above, large-scale trials are still necessary to evaluate the relationship between vitamin D levels, thyroid function, and AF. We thank Dr. Cerit for this great contribution to our work.
Dr. Hasan ARIReferences1 Gürdogan M, Ari H, Tenekecioglu E, Ari S, Bozat T, Koca V, et al. Predictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patients. Arq Bras Cardiol. 2016; 106(2):84-91.GürdoganMAriHTenekeciogluEAriSBozatTKocaVPredictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patientsArq Bras Cardiol2016106284912 Demir M, Uyan U, Melek M. The effects of vitamin D deficiency on atrial fibrillation. Clin Appl Thromb Hemost. 2014:20(1):98-103.DemirMUyanUMelekMThe effects of vitamin D deficiency on atrial fibrillationClin Appl Thromb Hemost2014201981033 Chen WR, Liu ZY, Shi Y, Yin W, Wang H, Sha Y, et al. Relation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patients. Ann Noninvasive Electrocardiol. 2014;19(2):166-73.ChenWRLiuZYShiYYinWWangHShaYRelation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patientsAnn Noninvasive Electrocardiol2014192166173Carta ao EditorPreditores de Recorrência de Fibrilação Atrial em Pacientes com Eutireoidismo e HipertireoidismoCeritLevent1Department of Cardiology - Near East University Hospital, Nicosia, CyprusCorrespondência: Levent Cerit, The Institute of Environmental Sciences, Bogazici University, Turquia. Near East University Hospital, Near East Street. CEP 07100, Nicosia. E-mail: drcerit@hotmail.com, drcerit@yahoo.comPalavras-chave:Fibrilação AtrialHipertireoidismo, Síndromes do Eutiroideo DoenteDoenças da Glândula Tireóide
Ao Editor,
Li com grande interesse o artigo intitulado "Preditores de Recorrência de Fibrilação Atrial em Pacientes com Eutireoidismo e Hipertireoidismo", publicado recentemente por Gürdogan et al.1 nos Arquivos Brasileiros de Cardiologia. Os investigadores relataram que as taxas de recorrência de fibrilação atrial (FA) foram semelhantes em pacientes com hipertireoidismo e eutireoidismo e que a duração da FA foi o único preditor de recorrência de FA em ambos.
O hipertireoidismo é um fator de risco conhecido para FA paroxística e permanente. Marrakchi et al.2 relataram que o nível sérico reduzido de hormônio estimulador da tireoide (TSH) é um fator de risco independente para a FA. Todos os outros fatores predisponentes para FA foram mencionados e discutidos neste artigo.
Adicionalmente, Demir et al.3 encontraram uma forte correlação entre a deficiência de vitamina D e a FA não valvar. Os níveis séricos de vitamina D correlacionaram com níveis de proteína C reativa ultrassensível e diâmetro atrial esquerdo, e estiveram significativamente associados à FA em pacientes chineses com FA persistente não valvar.4 Hanafy et al.5 mostraram os efeitos eletromecânicos diretos da administração de vitamina D no átrio esquerdo e encontraram que a vitamina D poderia prevenir efetivamente e corrigir a AF.
Em vista destes conhecimentos, Gürdoğan et al.1 deveriam ter citado em seu estudo os níveis de vitamina D dos pacientes e discutido a relação entre os níveis de vitamina D e a recorrência de FA.
Carta-respostaARIHasanDr.
Ficamos satisfeitos que o Dr. Cerit tenha mostrado grande interesse em nosso artigo intitulado "Preditores de Recorrência de Fibrilação Atrial em Pacientes com Eutireoidismo e Hipertireoidismo" publicado nos Arquivos Brasileiros de Cardiologia.1
Estudos recentes mostraram que a deficiência de vitamina D está associada à FA não valvar.2,3 No entanto, a relação entre ambos não é dependente da ocorrência de distúrbios tireoidianos. No estudo publicado por Demir et al.,2 os níveis de TSH estavam normais em todos os grupos com FA. Além disto, a disfunção tireoidiana foi um critério de exclusão nos estudos tanto de Demir et al.2 quanto de Chen et al.3 Nós não avaliamos o nível de vitamina D em nossos participantes, o que pode ser adicionado como uma limitação da nossa pesquisa. No entanto, os participantes do nosso estudo não relataram qualquer sintoma de deficiência de vitamina D ou tratamento para esta condição. Após cirurgia tireoidiana, em particular, os pacientes podem apresentar deficiência de vitamina D e hipotireoidismo, mas nenhum dos pacientes em nosso estudo apresentavam cirurgia tireoidiana prévia.
Considerando estas questões, estudos com grande número de pacientes ainda são necessários para avaliar a associação entre os níveis de vitamina D, função tireoidiana e FA. Nós agradecemos o Dr. Cerit por esta contribuição importante para o nosso trabalho.
Dr. Hasan ARIReferences1 Gürdogan M, Ari H, Tenekecioglu E, Ari S, Bozat T, Koca V, et al. Predictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patients. Arq Bras Cardiol. 2016; 106(2):84-91.GürdoganMAriHTenekeciogluEAriSBozatTKocaVPredictors of atrial fibrillation recurrence in hyperthyroid and euthyroid patientsArq Bras Cardiol2016106284912 Demir M, Uyan U, Melek M. The effects of vitamin D deficiency on atrial fibrillation. Clin Appl Thromb Hemost. 2014:20(1):98-103.DemirMUyanUMelekMThe effects of vitamin D deficiency on atrial fibrillationClin Appl Thromb Hemost2014201981033 Chen WR, Liu ZY, Shi Y, Yin W, Wang H, Sha Y, et al. Relation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patients. Ann Noninvasive Electrocardiol. 2014;19(2):166-73.ChenWRLiuZYShiYYinWWangHShaYRelation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patientsAnn Noninvasive Electrocardiol2014192166173