VALIDATION OF ELECTROCARDIOGRAPHIC CRITERIA OF LEFT ATRIAL ENLARGEMENT BY TRANSTHORACIC ECHOCARDIOGRAM

T. Huynh, P. Tran
McGill University Health Centre, Montreal General Hospital
1650 Cedar Avenue, Montreal, Quebec, CANADA H3G 1A4

Abstract: Previously described electrocardiographic criteria of left atrial enlargement were based on old echocardiographic M-mode measurements.  New measurements with phased-array 2-D echocardiography show that these criteria have poor accuracy, and suggest that other electrocardiographic criteria more sensitive for left atrial enlargement should be developed.

INTRODUCTION

Previously described electrocardiographic (EKG) criteria of left atria enlargement (LAE) were based mainly on old 1960 echocardiographic (echo) M-mode measurements [1-5].  We aimed to validate the sensitivity, specificity and accuracy of these criteria with the more sophisticated echocardiography technology currently available.

METHODS

We analyzed all patients who had echocardiography and EKG, within a one-month interval, during the year 2000.  The following criteria for LAE were studied:

Criteria 1: depth of the terminal negative portion of P wave in V1 >1 mm. 

Criteria 2: P wave duration in II, III, AVF > 0.12 sec.

We excluded all patients with paced rhythm, atrial fibrillation/flutter, artifacts and wandering EKG baseline.  All patients underwent standard transthoracic echo with a phased-array 2-D echocardiography machine HP5500.  LAE was diagnosed when LA maximal diameter was > 40mm in a parasternal view (Figures 1 and 2).

RESULTS

There were 104 pts with entirely normal echo and LA dimensions.  Their mean age was 47.0 + 15 years, and 53% were female.  Sixty-six (66) patients had LAE confirmed by echo.  These patients were older with mean age of 70.5±10.2, and 38% were female. Their mean LA diameter was 46.8 + 6.5mm (41-75). 

Criteria	Specificity	Sensitivity	Accuracy
Criteria 1	99.0%	7.6%	63.5%
Criteria 2	98.1	65.2%	85.3%

Figure 1:  Recorded 2-D echocardiogram/parasternal view.

Figure 2: Delineation of heart chambers from above view.  IVS: Interventricular septum; RV: Right ventricle; LV: Left ventricle; Ao: Aortic root; LA: Left atria.

Previous studies, based on old echo technologies, reported high accuracy of these two criteria. Compared to previous reports, our results suggested lower accuracy of these EKG criteria of LAE with very poor sensitivity of criteria 1.

DISCUSSION

Although highly specific, the current EKG criteria of LAE are poorly sensitive with accuracy ranging from 63.5%-85.3%. We suggest that other criteria more sensitive for LAE should be developed.

REFERENCES

[1] Miller DH, Eisenburg RR, Kligfield D, et al.  Electrocardiographic recognition of left atrial enlargement.  J Electrocardiography 1963;16:15-22.

[2] Munuswamy K, Alpert MA, Martin RH, et al.  Sensitivity and specificity of commonly used electrocardiographic criteria for left atrial enlargement determined by M-mode echocardiography. Am J Cardiol 1984;53:829-832.

[3] Chirife R, Gibson GS, Frankle WS.  Electrocardiographic detection of left atrial enlargement:  correlation of P wave with left atrial dimension by echocardiography.  Br Heart J 1975;37:1281-1288.

[4] Hazen MS, Marwick TH, Underwood DA. Diagnostic accuracy of the resting EKG in detection and estimation of left atrial enlargement: an echocardiographic correlation in 551 patients.  Am Heart Journal;122:3:823-828.

[5] Alpert MA, Munuswany K.  Electrocardiographic diagnosis of left atrial enlargement.  Arch Intern Med 1989;149:1161-1165.