Correction of the QT Interval in Children.

Aihoshi, Sogo; Yoshinaga, Masao; Tomari, Tsutomu; Nakamura, Makoto; Nomura, Yoshio; Oku, Shozo; Haraguchi, Tsutomu; Osawa, Norihito; Miyata, Koichiro

doi:10.1253/jcj.59.190

Cited by 10 publications

(22 citation statements)

References 21 publications

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“…20 Bazett formula overcorrects the QT interval at high heart rates. Pediatric cardiologists who participated in the program used age-and sex-specific criteria using an exponential formula (QT/RR 0.31 ) 21 or Fridericia formula. 22 In the screening program, cardiologists use computer-based QTc values as a reference because all ECG machines used in Japan are generally equipped with a function for automated measurement of QT intervals.…”

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confidence: 99%

Genetic Characteristics of Children and Adolescents With Long-QT Syndrome Diagnosed by School-Based Electrocardiographic Screening Programs

Yoshinaga

Kucho

Jav

et al. 2014

Circ: Arrhythmia and Electrophysiology

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Original ArticleBackground-A school-based electrocardiographic screening program has been developed in Japan. However, few data are available on the genetic characteristics of pediatric patients with long-QT syndrome who were diagnosed by this program. Methods and Results-A total of 117 unrelated probands aged ≤18 years were the subjects who were referred to our centers for genetic testing. Of these, 69 subjects diagnosed by the program formed the screened group. A total of 48 subjects were included in the clinical group and were diagnosed with long-QT syndrome-related symptoms, familial study, or by chance. Mutations were classified as radical, of high probability of pathogenicity, or of uncertain significance. Two subjects in the clinical group died. Genotypes were identified in 50 (72%) and 23 (48%) of subjects in the screened and clinical groups, respectively. Of the KCNQ1 or KCNH2 mutations, 31 of 33 (94%) in the screened group and 14 of 15 (93%) in the clinical group were radical and of high probability of pathogenicity. Prevalence of symptoms before (9/69 versus 31/48; P<0.0001) and after (12/69 versus 17/48; P=0.03) diagnosis was significantly lower in the screened group when compared with that in the clinical group although the QTc values, family history of long-QT syndrome, sudden death, and follow-up periods were not different between the groups. Conclusions-These data suggest that the screening program may be effective for early diagnosis of long-QT syndrome that may allow intervention before symptoms. In addition, screened patients should have follow-up equivalent to clinically identified patients. Thus, the aim of the present study was to determine the genetic characteristics of pediatric patients with LQTS who were diagnosed by a school-based screening program and whose genetic testing was performed and to compare results with subjects who visited hospitals because of the presence of LQTS-related symptoms, familial history, or who were diagnosed by chance. Methods Study PopulationThe study population included 117 unrelated probands ≤18 years of age who were referred to the Department of Pediatrics, Kagoshima University Hospital, Japan, between November 1993 and March 2005 or to the National Hospital Organization Kagoshima Medical Center from April 2005 to December 2012 for genetic evaluation. The population included 69 subjects who were screened by a school-based ECG screening program (Table 1). In the present study, LQTS-related symptoms were defined as syncope, aborted cardiac arrest, or sudden cardiac death at <30 years old. Subjects were divided into 2 groups on the basis of index events: subjects who were diagnosed by the schoolbased ECG screening program (screened group) and those who visited hospitals because of the presence of symptoms and family history or who were diagnosed by chance (clinical group; Table 1). Diagnosis of LQTS and Screening of QT Intervals in the School-based ECG Screening ProgramThe present study was a retrospective study, and diagnosis of LQTS and screening for prolo...

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Genetic Characteristics of Children and Adolescents With Long-QT Syndrome Diagnosed by School-Based Electrocardiographic Screening Programs

Yoshinaga

Kucho

Jav

et al. 2014

Circ: Arrhythmia and Electrophysiology

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“…Cutoffs used to screen children and adolescents with prolonged QT intervals, corrected according to Fridericia's formula, have previously been reported using automatically measured data for QT and RR intervals (QT/RR data). 9 The accuracy of automatic QTc measurements, however, is questionable in many cases, and should be supplemented by manual readings. 8 …”

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Cut-Offs for Screening Prolonged QT Intervals From Fridericia's Formula in Children and Adolescents

Hazeki

Yoshinaga

Takahashi

et al. 2010

Circ J

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Background:The corrected QT interval (QTc) according to Bazett's formula (QTc = QT/RR 1/2 ) has been used in clinical practice. Bazett's formula, however, overcorrects the QT interval at fast heart rates and undercorrects it at low heart rates. Guidelines and some investigators have recommended using Fridericia's formula (QTc = QT/RR 1/3 ) in these cases, especially in tachycardic subjects. The aim of the present study was to determine cutoffs for QTc suitable for screening pediatric subjects with prolonged QT intervals, based on manually measured values corrected by Fridericia's formula in a large number of subjects. Methods and Results:Three consecutive QT and RR intervals were measured in 4,655, 4,655, and 5,273 1st, 7th, and 10th graders, aged 6, 12, and 15 years, respectively. Each QT interval was corrected by Fridericia's formula, and mean values were calculated. Determination of the cut-offs for screening was based on the prevalence of abnormal electrocardiographic phenotypes of 1:1,164 and on the upper 0.025 percentile in the QTc distribution derived from previous studies. The tentative cut-offs suitable for screening subjects with prolonged QT intervals were 430 ms for 1st graders, 445 ms for 7th graders, and 440 and 455 ms for 10th grade boys and girls, respectively. Conclusions:These tentative cut-offs can be used to screen subjects with prolonged QT intervals in the clinical setting. Further studies are needed to confirm their validity. (Circ J 2010; 74: 1663 - 1669

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“…In most studies, the majority of participants were male (8 out of 10, with 3 of these 8 having a 100% male population). One study had a majority of female participants, 18 and 1 study included a 100% female population 24 . The mean age was provided for 5 studies and was within our age range of 14−35 years old 19–21,25,26 .…”

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confidence: 99%

“…| 1111 lowest R 2 values and was reported to be most accurate in terms of its ability to remove the effects of HR at all HR ranges. [18][19][20][21][22][23][25][26][27] Notably, Fridericia was the preferred method proposed by all of the cross-sectional studies, and no papers specifically discouraged the use of QTcF. [18][19][20][21][22][23][25][26][27] Additionally, three studies determined that Framingham was not suitable for use for QT correction in athletes and young people, 19,23,25 and was not specifically recommended by any of the included studies.…”

Section: Comparison Of Qt Interval Correction Methodsmentioning

confidence: 99%

“…There were no studies that supported the use of QTcB within young adults and athletes (Table 2). Nine studies concluded that QTcB was least reliable method for removing the effect of HR and was inaccurate at both high and low HRs across all age [18][19][20][21][22][23][25][26][27] These studies concluded that QTcB tends to overestimate QTc at higher HRs and underestimate at low HRs.…”

Section: Quality and Risk Of Bias Assessmentmentioning

confidence: 99%

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Comparison of methods for correcting QT interval in athletes and young people: A systematic review

Mahendran

Gupta

Davis

et al. 2023

Clinical Cardiology

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Screening elite athletes for conditions associated with sudden cardiac death is recommended by numerous international guidelines. Current athlete electrocardiogram interpretation criteria recommend the Bazett formula (QTcB) for correcting QT interval. However, other formulae may perform better at lower and higher heart rates (HR). This review aimed to examine the literature on various QT correction methods in athletes and young people aged 14−35 years and determine the most accurate method of calculating QTc in this population. A systematic review of MEDLINE, EMBASE, Scopus, and SportDiscus was performed. Papers comparing at least two different methods of QT interval correction in athletes or young people were included. Quality and risk of bias were assessed using a standardized tool. The search strategy identified 545 papers, of which 10 met the criteria and were included. Nine of these studies concluded that QTcB was least reliable for removing the effect of HR and was inaccurate at both high (>90 beats per min [BPM]) and low (<60 BPM) HRs. No studies supported the use of QTcB in athletes and young people. Alternative QT correction algorithms such as Fridericia (QTcF) produce more accurate correction of QT interval at HRs seen in athletes and young people. QTcB is less accurate at lower and higher HRs. QTcF has been shown to be more accurate in these HR ranges and may be preferred to QTcB for QTc calculation in athletes and young people. However, accurate QTc reference values for discrete HRs using alternative algorithms are not well established and require further research.

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Correction of the QT Interval in Children.

Cited by 10 publications

References 21 publications

Genetic Characteristics of Children and Adolescents With Long-QT Syndrome Diagnosed by School-Based Electrocardiographic Screening Programs

Genetic Characteristics of Children and Adolescents With Long-QT Syndrome Diagnosed by School-Based Electrocardiographic Screening Programs

Cut-Offs for Screening Prolonged QT Intervals From Fridericia's Formula in Children and Adolescents

Comparison of methods for correcting QT interval in athletes and young people: A systematic review

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