Clinical relevance of ECG abnormalities in community-based cardiovascular screening

Background

The 12-lead electrocardiogram (ECG) is an accessible, low-cost tool able to detect abnormalities suggestive of heart disease. However, its contribution to cardiovascular screening remains insufficiently defined. This study evaluated the prevalence and clinical significance of ECG abnormalities identified during a population-based screening programme.

Methods

A cross-sectional screening was conducted in three Portuguese communities. Eligible participants were volunteers aged ≥40 years or <40 years with a premature family history of coronary artery disease. Standardised evaluation included questionnaires, anthropometry, blood pressure, lipid profile, high-sensitivity CRP (hsCRP) and a resting ECG; optional venous blood sampling was offered. ECG abnormalities included non-sinus rhythm, pathological Q waves, ST-segment deviation, inverted or biphasic T waves, conduction disturbances and other investigator-reported alterations. Clinical, analytical and behavioural characteristics were compared.

Results

ECG abnormalities were present in 29% of the 198 screened individuals (n=58). The most frequent findings were minor abnormalities (22%), followed by conduction disturbances (5%), inverted T waves (3.7%), rhythm disturbances (3.7%) and pathological Q waves (2.5%). Most participants had a single abnormality (26%), while two abnormalities occurred in 4%.

Participants with ECG abnormalities were older (71 vs 65 years, p<0.001) and had more dyslipidaemia (69% vs 50%, p=0.015) and alcohol use (43% vs 28%, p=0.04). They also showed lower rates of active smoking (3.4% vs 13%, p=0.046) and lower hsCRP levels. Global cardiovascular risk was significantly higher in the abnormal-ECG group (p=0.02): 92% were classified as high or very-high risk versus 74% with normal ECGs. Two ECG-triggered cardiology referrals occurred: one supraventricular tachycardia and one pattern suggestive of apical hypertrophic cardiomyopathy.

Conclusions

Although abnormalities suggestive of coronary artery disease were uncommon, ECG abnormalities were strongly associated with greater cardiometabolic burden and higher estimated cardiovascular risk. The ECG also enabled early identification and referral of clinically significant conditions. Despite the moderate overall prevalence of abnormalities, these findings support the ECG as a valuable complementary tool in community screening, helping detect individuals at high or very-high cardiovascular risk and conditions requiring specialist evaluation.