Auricular overloadings: Electrocardiographic analysis of 193 cases

Abstract

The authors studied the auriculograms of 193 patients presenting mitral lesions (41 cases), congenital cardiac malformations (100 cases), and pulmonary disease (52 cases). In the great majority of the cases hemodynamic correlations were established and in 20 patients the vectorcardiogram was analyzed. The chief characteristics of the P wave and the P vector in left, right, and combined atrial overloading are stressed. The following conclusions are drawn: 1. (1) The most important findings for left atrial overloading are a marked backward orientation of the P vector, appearance of notching and increase in the duration of the P waves in the limb and left precordial leads. 2. (2) There seems to exist a correlation between the duration of the P waves and the degree of left atrial dilatation. 3. (3) P waves with normal duration may exist in the presence of hypcrtrophied but not significantly dilated left auricles. 4. (4) A tendency of the AP to deviate to the right in patients with mitral lesions was found whenever the right auricular pressures were elevated. 5. (5) In all cases of significant right auricular systolic overloading (systolic pressure above 10 mm Hg) in our series of congenital heart diseases, the amplitude of the P waves was above 2 mm either in the limb or precordial leads. 6. (6) Arterial oxygen desaturation tends to increase the amplitude of the P waves. Patients with both elevated right atrial pressures and arterial desaturation presented the highest P waves in this study. 7. (7) Slight degrees of right atrial overloading, particularly in patients with interatrial septal defect, were detected in many cases by the presence of peaked P waves of normal amplitude, mostly in V 1 and V 2. 8. (8) The interpretation of the ventricular complex adds important data in the diagnosis of right atrial overloading. 9. (9) Pulmonary emphysema and arterial desaturation as a consequence of disturbance in the mechanism of hematosis, in patients with chronic disease of the lungs, produce marked changes in the P waves and the P vector. The P waves become tall and peaked and the AP is deviated rightward and downward. 10. (10) In the presence of pulmonary emphysema with arterial desaturation, it is very difficult to decide by the auriculogram whether there also exists right auricular overloading. 11. (11) The existence of combined auricular overloading may be suspected from the ECG for two reasons: (a) the presence of morphologic signs compatible with overloading of both atria; (b) the existence of morphologic signs of left atrial overloading associated with a tendency of the AP to deviate to the right. 12. (12) Vectorcardiogram: P loops with leftward and backward orientation, increased in width, and sometimes showing eight-shaped figures are very suggestive of left atrial overloading. P loops with normal width, increased magnitude and a forward orientation are diagnostic of right atrial overloading.