By Michael H. Crawford, MD
Professor of Medicine, Chief of Clinical Cardiology, University of California, San Francisco
Dr. Crawford reports no financial relationships relevant to this field of study.
SYNOPSIS: This study of almost 15,000 young caucasian subjects that included 32% women and 20% athletes showed that T-wave inversion in ECG leads V1 and 2 is a normal variant. T-wave inversions extending beyond V2 are rare and may warrant further evaluation, but in this study no such individuals exhibited cardiac abnormalities.
SOURCES: Malhotra A, Dhutia H, Gati S, et al. Anerior T-wave inversion in young white athletes and nonathletes prevalence and significance. J Am Coll Cardiol 2017;69:1-9.
Kirchhof P, Fabritz L. Anterior T-wave inversion does not convey short-term sudden death risk: Inverted is the new normal. J Am Coll Cardiol 2017;69:10-12.
ECG T-wave inversions (TWI) in the anterior precordial leads generally are considered abnormal, but precise criteria are lacking. Investigators from England analyzed a convenience population of 14,646 young (16-35 years of age), Caucasian, apparently healthy adults (32% women), which included 2,950 (20%) athletes. Although not sponsored by the National Health Service, several elite sporting organizations in England underwrote annual medical testing of their member athletes through the charitable organization CRY (cardiac risk in the young). The CRY also tested any young adult who desired testing. The evaluation included history, physical examination, ECG, and referral for further testing in those with abnormal findings or designated as research controls. Subjects with cardiac symptoms and a history or family history of cardiac disease or premature sudden cardiac death or complete right bundle branch block were excluded. All subjects in this population underwent echocardiography, and those with abnormal ECGs were subjected to ambulatory ECG monitoring, exercise testing, signal averaged ECG, or cardiac MRI. Those with TWI in two or more contiguous anterior precordial leads (V1-4) were considered abnormal, and this was discovered in 338 (2.3%) subjects. It was more common in women (4.3%) than men (1.4%; P < 0.0001) and in athletes compared to nonathletes (3.5% vs. 2%; P < 0.0001). In athletes, it was more common with endurance athletes than strength athletes. It was confined to leads V1-V2 in 77% of all cases, with only 78 (0.5%) showing TWI beyond V2. Echocardiography in 338 of the abnormal TWI subjects (103 athletes, 235 nonathletes) were compared to 1,848 (1,079 athletes) without anterior TWI. No differences in cardiac structure or function were detected. Cardiac MRI was performed in 250 with anterior TWI. No evidence of arrhythmogenic right ventricular cardiomyopathy (ARVC), hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy, or myocardial scar were detected. During the mean follow-up of 23 months, no one with anterior TWI experienced a cardiac event. The authors concluded that TWI confined to ECG leads V1-V2 is a normal variant, but TWI beyond V2 is rare and may warrant further investigation.
ECG anterior precordial TWI has been suggested as a screening tool for the further evaluation of otherwise healthy adults because it is common in ARVC, HCM, and other cardiomyopathies. Since the European Society of Cardiology (ESC) recommended ECG screening in all pre-participation sports health examinations, it is a trigger finding for further testing. However, it is known to be more common in athletes, especially those of Afro-Caribbean origin and, thus, its value is questionable. Also, there are little data in Caucasians about this finding. Therefore, this study from the United Kingdom is of interest. The strength of the study is its large size (almost 15,000), reasonable proportion of women (32%) and athletes (20%), and the liberal use of further testing in those with anterior TWI (echo 100%), cardiac MRI (74%), signal-averaged ECG (93%), ambulatory ECG monitoring (87%), and exercise ECG testing (81%). Also, the anterior TWI group was followed for two years. In addition, the ECGs were performed correctly using the American Heart Association-recommended submammary lead placement in women, rather than the often-performed placement of V3-6 below the brassiere. It was not a randomized trial and may have suffered from selection bias, but the large size partially mitigates this limitation. Finally, ARVC is believed to be accelerated by exercise, so we cannot exclude that the anterior TWI is not an early sign of disease that cannot be confirmed by imaging yet. Although no events occurred during two years of follow-up, this was a cross-sectional study and no further imaging was conducted after the baseline testing.
The results support the Seattle consensus recommendations to consider further evaluation only if the TWI goes beyond V2, rather than the ESC recommendation of beyond V1. However, ARVC is more common in continental Europe, especially Italy, than in the United Kingdom or the United States, which may justify more sensitive criteria. The trade-off is lower specificity, which is a problem because of the unnecessary anxiety, delay of participation, and cost of pursuing further testing. In fact, these investigators do not even strongly recommend further testing when the TWI is beyond V2, because no one with anterior TWI in their study was found to have a cardiomyopathy. Of course, those with symptoms or signs or a family history of cardiac disease were excluded. Thus, one could argue that these criteria are worthless. In fact, this very lack of specificity is why the American Heart Association still does not recommend ECG screening for pre-participation evaluation of asymptomatic athletes without a family history or physical exam findings suggestive of heart disease. The accompanying editorial concludes that we need better tools to exclude these rare cardiomyopathies. I agree.