#Intervalo qt normal ecg series#

7 When the parents did not belong to the same ethnic group, the infants were included in a mixed group. The following variables were also recorded: birth weight, sex, water-electrolyte imbalances, or drugs taken by the mother that could have lengthened the QTc interval, and the ethnic group of the parents, according to the classification of Black. 6 In cases of discrepancies of over 10 ms, the value was agreed upon by consensus. The PR, RR, and QT intervals were measured in lead II and the QTc interval corrected for heart rate was calculated according to the Bazett formula, following the European guidelines for the interpretation of the neonatal ECG. It was connected to a computer, in which the data were then analyzed, that allowed up to an 8-fold amplification of the recording and the use of markers for the correct measurement. An approved Trim II electrocardiograph (Philips, Inc., Eindhoven, The Netherlands) was utilized. The ECG was interpreted independently by 2 different cardiologists in order to avoid inter-observer variation.

#Intervalo qt normal ecg series#

The purpose of this study is to assess the prevalence of these channelopathies on the basis of changes in the neonatal ECG in a cohort of consecutive newborns from a hospital in a multiethnic city like Barcelona, Spain.īetween November 2005 and November 2006, a consecutive series of full-term newborn infants underwent ECG at Hospital del Mar in Barcelona within the first 48 hours of life and with the infant in a tranquil state. 2 Finally, the SQTS was identified recently, 5 and its prevalence among newborn infants is also unknown. With respect to BS, there are no data on Japanese infants, but the prevalence among adults is 146.2/100 000 population. In the case of LQTS, there is a large-scale Italian registry 4 including more than 34 000 newborn infants that established a cutoff point for a normal QT interval corrected for heart rate (QTc) at 440 ms, with a prevalence of 0. The prevalence of these entities in Spain is unknown. Some authors attribute a percentage of sudden infant death syndrome (SIDS) to these channelopathies. The channelopathies most easily recognized by means of ECG, in addition to LQTS, are the Brugada syndrome (BS), which affects the sodium channel, and the short QT syndrome (SQTS), which affects the potassium channel. 2 Some of them may be suspected on the basis of the surface electrocardiogram (ECG), although, given the differences in penetrance, there are patients with these disorders and high risk of sudden death in whom they may be masked. 1 They are included among the so-called channelopathies, and genetic studies have enabled us to identify them as entities in their own right. Long QT syndrome (LQTS) is produced by alterations in the genes that encode different ion channels (mainly the potassium and sodium channels) that lead to potentially malignant cardiac arrhythmias.