Background: Anatomical left atrial enlargement is associated with significant cardiovascular morbidity and mortality, heart failure, stroke, atrial fibrillation and diastolic dysfunction. This concept is more pronounced in hypertensive population, who have an especially increased risk of LA enlargement from diastolic dysfunction when compared to the general population. However, left atrial enlargement may not be correlated with basic investigation such as electrocardiographic (ECG) criteria. In the past, studies usually correlating ECG criteria with anatomic measures mainly used an inferior M-mode or two dimensional echocardiography; moreover, these were applied in the general population, not hypertensive patients. In the present study it was sought to determine the accuracy of the ECG criteria to diagnose anatomical left atrial enlargement in a hypertensive population, as determined by volumetric cardiovascular magnetic resonance imaging (CMR).
Material and Method: A total of 230 consecutive hypertensive patients referring for CMR (46.2% males, mean age 71.5+10.44 years) were enrolled. The ECG criteria for left atrial enlargement (LAE) was analyzed as well as left atrial volume index using the biplane area-length method from CMR. ECG criteria for LAE were assessed by investigator blinded to CMR data.
Results: Mean SBP/DBP at the time of CMR was 140/67+18.5/9.7 mmHg. Mean BMI was 26.8+4.7 kg/m2, co-morbid diseases were as follows; DM, 68 patients (57.1%) and dyslipidemia 67 patients (56.3%). Mean LA volume index was 59.77+17.93 ml/m2 and mean LVEF was 63.18+7.16%. The prevalence of CMR (with the cut-off point of 28 ml/m2) LAE was 98% and by any ECG criteria, was 47%. Sensitivity of individual ECG criteria for LAE, p>120 ms was 49.6%, biphasic P wave in V1 was 30.8%, and P notch >40 ms was 9.7%. If combined, ECG criteria p>120 ms and biphasic P wave in V1, sensitivity increased to 58.1%, that was higher than individual criteria. Specificity of individual ECG criteria for LAE was 100%.
Conclusion: In the LAE from ECG criteria, at least one criteria is not sensitive for anatomical LAE but for specificity in hypertensive population. For individual criteria, p>120 ms had the highest sensitivity. These findings from our study emphasized the lack of sensitivity of LAE by ECG criteria in hypertensive patients. Therefore, LAE by ECG criteria might be discovered too late to be the prognosticator in hypertensive patients.

Keywords: Left artrial enlargement, ECG, MRI