T wave morphology and QRS voltages in adolescents with T wave inversion: relevance for family screening

Abstract Background T wave inversion (TWI) in young apparently healthy individuals may be suggestive of an underlying cardiomyopathy. T wave and QRS morphology in these individuals may predict the presence of other family members harbouring cardiomyopathy. Purpose The aim of this study was to evaluate whether T wave morphology (depth and width) and QRS voltages (QRSV) in screened adolescent individuals may predict an abnormal baseline evaluation in screened relatives. Methods Data (health questionnaire and ECG) was obtained from a nationwide cardiac screening program in adolesecents (BEAT-IT). Individuals with pathological TWI were recruited. Those with non-persistent anterior TWI at 16 years were excluded. Data on T wave depth mV, width ms, and peak-to-peak QRSV mV in leads with TWI (excluding V1 / aVR) were measured with callipers using Philips IntelliSpaceECG. The mean depth, width and QRSV for all leads with TWI were recorded. The mean ratios comparing all 3 variables were also computed. Continuous variables were statistically evaluated with the student T-Test or Mann Whitney U Test (depending on normality distribution). Recruited probands were placed into two groups, depending on the outcome of family screening. A positive outcome was defined as ≥1 family member with an abnormal screen. Results The total cohort consisted of 2672 subjects (mean 15 years, males 50.4%, 95.8% Caucasian, 38.9% competitive athletes). Sixteen subjects had TWI (n=6 Lateral, n=6 Anterior, n=3 isolated Inferior, n=1 Anterior/Inferior). A third had TWI in multiple territories (n=5/16, 31.3%). One was given a diagnosis (HCM). A fourth had a clinically actionable variant (CAVs) (n=2 MYH7, n=1 ACTC1, n=1 MYBPC3). Family screening (n=87 relatives) lead to 9 families having at least one family member with an abnormal baseline evaluation (53.3%). Half of families had at least one relative with an abnormal ECG (n=8, 50.0%). A diagnosis was present in 3 families (18.8%) (n=2 HCM, n=1 DCM). All these relatives had CAVs. QRSV / T wave characteristics in probands with anterior TWI were similar in all probands, irrespective of the outcome of family screening. ECG data for probands with non-anterior TWI were analysed separately. T wave depth (p=0.033), T wave depth-to-width ratio (p=0.033) and T wave depth-to-QRSV ratio (p=0.033) were all found to be higher in families with a positive outcome (Table 1). ROC curve analysis showed that all 3 variables (AUC 0.952 and p=0.030 for all 3) performed extremely well in discriminating the outcome of family screening (Table 1). Cut off values are also tabulated in table 1. Conclusion QRSV and T wave morphology in probands with TWI can be surrogate predictors for the outcome of family screening at baseline. Relatives of probands with non-anterior TWI exhibiting deeper T waves, a higher T wave depth-to-width ratio, and a higher T wave depth-to-QRSV ratio were able to effectively distinguish the outcomes of family screening.