Microvolt T-wave alternans during Holter monitoring in children and adolescents.
BACKGROUND
Time-domain microvolt T-wave alternans (TWA) has been described as a noninvasive marker of sudden cardiac death in adults. The incidence of TWA in pediatric populations has not been defined well. The aim of the study was to determine peculiarities of TWA in children.


METHODS
We examined 68 healthy patients-newborns (20) and children in age group of 7-17 years (48)-and 85 pediatric patients: ventricular premature beats-65; dilated cardiomyopathy (DCMP)-2; long QT syndrome (LQTS)-10; Brugada syndrome (BrS)-5, catecholaminergic ventricular tachycardia (CVT)-3. All underwent Holter monitoring (HM) with definition of the peak value of TWA by modified moving average method.


RESULTS
In healthy newborns, TWA was 32 +/- 8 (12-55) microV (HR 123-156 bmp). In healthy children (7-17 years) it was 30 +/- 11 (10-l 55) microV, (HR 64-132 bmp) without any differences between boys and girls. In all group of patients, TWA were significantly higher (P < 0.05) than in healthy. Circadian peak of TWA was found (90%) in a second part of day and at sleep (8%). Among them 60% (LQTS, BrS, and DCPM) had TWA > 55 microV.


CONCLUSIONS
Time-domain TWA during HM in children was independent of age, gender, and heart rate. In 94% healthy children, values of TWA do not exceed 55 microV but 20-50% children with cardiac pathology had TWA more than 55 microV. Night circadian type of TWA in diseases with risk of life-threatening arrhythmias associated with TWA was more than 55 microV.
Center for Syncope and Cardiac Arrhythmias in Children and Adolescents of the Federal Medical-Biological Agency of Russia, Clinical Children Hospital of Federal Medical-Biological Agency of Russia, Moscow, Russia. leonidmakarov@yahoo.com <leonidmakarov@yahoo.com>
Leonid
L
Makarov
Vera
V
Komoliatova
D000293:Adolescent; D017677:Age Distribution; D053840:Brugada Syndrome / Q000503:physiopathology; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology; D002648:Child; D015716:Electrocardiography, Ambulatory / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000503:physiopathology; D008297:Male; D017180:Tachycardia, Ventricular / Q000503:physiopathology; D018879:Ventricular Premature Complexes / Q000503:physiopathology