[Relation of electrocardiographic features and distribution of hypertrophy in hypertrophic non-obstructive cardiomyopathy during childhood].

The relationship between the electrocardiographic features and the distribution of ventricular hypertrophy in pediatric patients with hypertrophic non-obstructive cardiomyopathy (HNCM) aged from 6 to 16 years (mean 11.6 years) was studied during a period of 6 months to 10 years (mean 3.9 years). Hypertrophy in the three segments (anterior septum, lateral free wall, posterior free wall) of the left ventricle in 17 patients with HNCM was evaluated by two-dimensional echocardiography (short-axis cross section of the left ventricle) at the end-diastolic period. The 17 patients were divided into four groups according to the echocardiographic findings as follows: Group A: hypertrophy in the ventricular anterior septum with or without posterior septum (eight patients). Group B: hypertrophy in both the ventricular septum and lateral left ventricular free wall (three patients). Group C: hypertrophy in the lateral left ventricular free wall (three patients). Group D: hypertrophy in the posterior left ventricular free wall with or without posterior septum (three patients). The incidence of electrocardiographic abnormalities in each group was analyzed using serial standard 12-lead electrocardiography. Electrocardiographic abnormalities and the distribution of the ventricular hypertrophy were related as follows: Lateral free wall: increased SV1 + RV6 (p < 0.05), ST-T change in leads V5.6 (p < 0.01). Posterior free wall: ST-T change in leads II.aVF (p < 0.05). Electrocardiographic abnormalities in HNCM patients in the hypertrophy were: Group A: abnormal Q waves in leads II.III.aVF (75%) and V5.6 (50%), high voltage R waves in leads II.III.aVF (25%) and V1 (38%), low voltage R waves in leads V2.3 (13%) and V5.6 (38%), and ST-T changes in leads I.aVL (25%), II.aVF (13%) and V2-4 (50%). Group B: abnormal Q waves in leads II.III.aVF (33%), high voltage R wave in lead V1 (33%), increased SV1 + RV6 (67%), low voltage R waves in leads V2.3 (33%) and V5.6 (33%), and ST-T changes in leads I.aVL (33%), II.aVF (33%), V2-4 (67%) and V5.6 (67%). Group C: abnormal Q waves in leads I.aVL (33%) and V5.6 (33%), high voltage R waves in leads II.III.aVF (33%), V1 (67%) and V5.6 (33%), increased SV1 + RV6 (67%), low voltage R waves in leads V5.6 (33%) and ST-T changes in leads II.aVF (33%), V2-4 (33%) and V5.6 (67%).