Cardiac screening with ECG in the young: significance of T wave inversion, T wave depth and T wave/QRS ratio

Abstract

Abstract Background In young apparently healthy individuals, repolarization changes at the ECG may suggest an underlying cardiomyopathy. Purpose This study aims to investigate the clinical significance of T waves depth and T/QRS ratio in young individuals who underwent cardiac screening and exhibited T wave inversion (TWI) at the ECG. Methods We analysed a database of individuals aged 14 to 35 years who underwent cardiac screening, which included a health questionnaire and 12-lead ECG with a charitable organisation, between 2008 and 2013. All individuals included had recently responded to a follow-up online health questionnaire or had documented outcomes on a national digital database. The amplitudes of QRS (peak to peak) and T waves (mV) were measured in the leads where TWI was present; the average T/QRS ratio and average TWI depth were calculated. Results Our cohort comprised 5360 subjects (mean age of 21 ± 6 years, 61% males). Of the 358 (7%) who were referred for further investigations based on their screening findings, 255 (5%) had an abnormal ECG. TWI was documented in 120 (2%) individuals [anterior TWI in 78, inferior TWI in 16, lateral TWI in 6, and overlaps in 20 cases]. After further investigations, 16/120 (13%) individuals were diagnosed with cardiomyopathy [9 hypertrophic cardiomyopathy (HCM), 5 arrhythmogenic cardiomyopathy (ACM), 1 dilated cardiomyopathy (DCM), and 1 left ventricular non-compaction cardiomyopathy (LVNC)]. Of the remaining 104/120 individuals, 18 were diagnosed with other cardiac conditions and 86 were not found to have a cardiac disease. During a mean follow-up of 8.1 ± 1.2 years, no deaths were documented among the 16 individuals diagnosed with a cardiomyopathy, but 3 of them experienced a sudden cardiac arrest (all of them had ACM). In individuals diagnosed with a cardiomyopathy both average T/QRS ratio and average TWI depth were higher compared to the rest (0.128 vs 0.117; p = 0.54 and 0.281 vs 0.162 mV; p = 0.03, respectively). Average T/QRS ratio and average TWI depth were higher in individuals diagnosed with HCM compared with the ones diagnosed with other cardiomyopathies (0.133 vs 0.115; p = 0.68 and 0.336 vs 0.164 mV; p = 0.05, respectively). Conclusion T wave inversion is a relatively common ECG finding in young apparently healthy individuals and this feature leads to a diagnosis of cardiomyopathy in 13% of cases. Among subjects exhibiting TWI, T/QRS ratio and T wave depth appear higher in the ones who are eventually diagnosed with cardiomyopathies.Figure 1.Flowchart of patient selection