Auricular premature systole: I. Aberration of the ventricular complex in the electrocardiogram

Abstract

1. 1. The electrocardiograms of 201 patients who had auricular premature systoles (APS) were analyzed. One thousand three hundred six APS were found, and were divided into five groups according to the degree of their prematurity. Multiple APS of the same degree of prematurity occurring in one record were counted as one “type.” Multiple APS of different degrees of prematurity were counted as different “types.” The total number of “types” of APS was 525. Eight of these were blocked. 2. 2. APS with aberration of the ventricular complexes were three times as frequent as APS without aberration. 3. 3. If no aberration is present, the APS may be overlooked, or the irregularity may be misinterpreted as sinus arrhythmia. 4. 4. Aberration, especially of the T wave, is often more marked in the chest leads. Chest leads may thus aid in the recognition of APS. 5. 5. Forty-three types showed no aberration of QRS, but showed aberration of the RS-T segments or the T waves. 6. 6. Three hundred thirty-seven types of APS showed aberration of the QRS complexes. 7. 7. If aberration of QRS was of slight degree, increase or decrease in amplitude was the most frequent single change: changes in configuration (slurring, notching, appearance of a Q wave) were next in frequency; changes in duration occurred seldom except in conjunction with other changes; a reversal of direction never occurred alone. 8. 8. The higher degrees of aberration were less frequent than the lower. They consisted of changes in amplitude combined with changes in configuration, or various combinations of changes in amplitude, configuration, duration, and direction. 9. 9. The highest degree of aberration (twenty-eight types) affected all four characteristies of the QRS complex, amplitude, configuration, duration, and direction. APS with such bizarre ventricular complexes are commonly mistaken for ventricular premature systoles. 10. 10. The degree of prematurity of an APS is a major factor in determining the degree of its aberration. This was shown by the following facts: 10.1. a. None of the twenty-eight types of APS with very marked aberration occurred late in diastole. 10.2. b. None of the thirty-five types of APS without any aberration occurred very early in diastole. 10.3. c. None of the 101 types of APS occurring late in diastole showed more than moderate aberration. 10.4. d. None of the six types of APS occurring very early in diastole were free from aberration. 11. 11. The degree of prematurity is not the only factor which determines the degree of aberration. This was shown by the following facts: 11.1. a. Of one hundred types of APS occurring early in diastole, eleven showed no aberration. 11.2. b. Most electrocardiograms showing different types of APS in the same record revealed a lack of parallelism between aberration and the degree of prematurity; aberration often remained the same or became less marked as the degree of prematurity increased. 12. 12. No definite relationship was found to exist between the number of APS in a given record and the aberration of their ventricular complexes. 13. 13. P-R interval changes in APS had no influence on the aberration of their ventricular complexes. 14. 14. The patient's age had no influence on aberration. APS with marked aberration were found in children. APS without any aberration were found in patients over 70 years of age. 15. 15. Aberration occurred in normal and abnormal electrocardiograms. Aberration of all degrees occurred in noncardiac patients as frequently as in cardiac patients. Aberration was no more frequent in the presence of congestive heart failure than in its absence. 16. 16. Three cases are reported. Their serial records showed that significant changes in the degree of aberration of the APS occurred within a few days. In two cases, the change was probably brought about by the administration of quinidine, and, in the third, by a severe infection (pneumonia). 17. 17. Aberration of the ventricular complexes of APS reflects changes in intraventricular conduction; these changes may be physiologic; or they may be pathologic and may then be produced by diseases or by drugs affecting the conduction system, e. g., quinidine. 18. 18. Quinidine selectively affects APS by increasing their aberration, especially the duration of QRS. 19. 19. A change in the degree of aberration is more significant than aberration itself. It indicates a change in the condition of the heart which the remainder of the electrocardiogram may not clearly reveal.