Electrocardiographic detection of hypertensive left atrial enlargement in the presence of obesity: re-calibration against cardiac magnetic resonance

Abstract

Left atrial enlargement (LAE) has adverse prognostic implications in hypertension.We sought to determine the accuracy of 5 ECG criteria for LAE in hypertension relative to cardiac magnetic resonance (CMR) gold-standard, and investigate the effect of concomitant obesity. 130 consecutive patients (age: 51.4 ± 15.1 years, 47% male, 51% obese, systolic blood pressure: 171 ± 29mmHg, diastolic blood pressure: 97 ± 15mmHg) referred for CMR (1.5T) from a tertiary hypertension clinic were included. Patients with concomitant cardiac pathology were excluded. ECGs were assessed blindly for: 1) P wave >110ms, 2) P mitrale, 3) P wave axis <30°, 4) Area of negative P terminal force in V1 >40ms·mm and 5) Positive P terminal force in aVL >0.5mm. LA volume ≥55ml/m 2 , measured blindly by CMR, was defined as LAE.Sensitivity, specificity, positive predictive value, negative predictive value, accuracy and area under the receiver operator curve were calculated. The prevalence of LAE by CMR was 26%. All the individual ECG LAE criteria were more specific than sensitive, with specificities ranging from 70% (P axis <30 o ) to 99% (P mitrale). Obesity attenuated the specificity of most of the individual ECG LAE criteria. Obesity correlated with significant lower specificity (48% vs 65%, P < 0.05) and a trend towards lower sensitivity (59% vs 43%, P = 0.119) when ≥1 ECG LAE criteria were present. Individual ECG criteria of LAE in hypertension are specific, but not sensitive, at identifying LAE. The ECG should not be used to excluded LAE in hypertension, particularly in obese subjects.

Sensitivity and specificity of ECG criteria of left atrial enlargement in comparison to cardiac magnetic resonance in patients with hypertrophic cardiomyopathy

“…Rodrigues et al also demonstrated higher specificity than sensitivity of ECG criteria, but the differences between sensitivity and specificity were larger than in our study. Contrary to our study, the authors observed higher specificity for the lead II than the lead V1 criterion [91% vs. 81%] [15] . They also observed that obesity was a strong attenuation factor for specificity.…”

“…Previous studies comparing electrocardiographic criteria with CMR for LA size assessment in other patient populations produced results similar to ours. In the majority of these studies the prevalence of LA enlargement by CMR was much lower than in ECG and varied between 20 and 30% [14][15][16] . It was higher only in the study by Burekaam et al, but the authors decided to choose a lower cut-off value for LA enlargement as compared to our and other studies [16] .…”

Electrocardiographic criteria for cardiac remodeling in hypertensive patients

“…Additionally, the authors did not compare various ECG criteria for LAE in order to determine which index had the best accuracy. Other investigators used different imaging methods for evaluation of LA volume (echocardiography and cardiac magnetic resonance) and found high specificity, but low sensitivity of ECG‐derived criteria for detection of LAE …”

“…The investigators used LA volume index derived by echocardiography as the gold standard method. Rodrigues et al found that individual ECG criteria of LAE in hypertension were specific, but not sensitive, in the diagnosis of LAE. As the reference imaging method for determination of LA volume, they used cardiac magnetic resonance and concluded that ECG should not be used to exclude LAE in the patients with arterial hypertension .…”

“…Rodrigues et al found that individual ECG criteria of LAE in hypertension were specific, but not sensitive, in the diagnosis of LAE. As the reference imaging method for determination of LA volume, they used cardiac magnetic resonance and concluded that ECG should not be used to exclude LAE in the patients with arterial hypertension . The authors compared five different ECG criteria for LAE, including PTFV1, and did not show significant difference in accuracy between them.…”