The present studies were undertaken in an attempt to formulate an accurate expression of the relationship between the duration of left ventricular ejection and heart rate in man. On the basis of regression equations relating the duration of left ventricular ejection and heart rate in normal individuals, the index LVET + .0016 HR was derived and tested in normal adults and prepubertal children. The left ventricular ejection time index (ETI) remained constant and reproducible over the range of heart rate from 50 to 150 and yielded more consistent values in this range of heart rate than did previously derived equations. A slight but significantly higher value of the ETI was present in the adult females when compared to the adult males, while no significant difference according to sex was apparent in the children. A decrease in ETI was found when cardiac output was diminished in normal individuals during 60° head-up tilt and in patients with congestive heart failure. Of note was the finding of a significant correlation between the level of the ETI and the cardiac output in these situations. Submitted on December 13, 1962

Research on the early development of auditory localization responses is reviewed and the existence of a U-shaped developmental function is described. It has been reported that many newborns turn towards off-centred sound sources reliably at birth and will perform well for approximately the first month of life, poorly during the second and third months, and well again during the fourth month. This trend was confirmed in three of four infants who were tested extensively throughout their early months. The fourth baby failed to show reliable orientation towards sounds until the fourth month of life. During the period of temporary performance decrement, attempts to reinstate reliable responding by either introducing meaningful acoustic stimuli or eliminating possible auditory-visual conflicts were not successful. Potential explanations for this temporary decline in auditory orientation responses are discussed.*We wish to thank A. Muir, J. Rodger, and P.C. Dodwell for their helpful criticisms of this paper; M.K. Buell, H. Killen, B. Pater, and M. Sinclair who helped us test some of the babies; L. Paterson who helped score tapes; Rachel Clifton who helped us acquire a low-light-level videocamera; and A. Lister who typed the manuscript. We would also like to thank the mothers and their infants (J-H.

LEVY et al.1 described "aortico-left ventricular tunnel" as an abnormal communication that begins in the ascending aorta above the level of the coronary arteries, bypasses the aortic valve, and terminates in the left ventricle, resulting in aortic insufficiency. The authors described three cases and stated that four similar cases had been previously described. A review of the original papers2-5 suggests, however, that in three instances the history and anatomic findings were more compatible with rupture of a congenital aneurysm of a sinus of Valsalva than with an aortico-left ventricular tunnel. Levy et al.' made the point that in their three cases, and in another previously described by Edwards,3 the tunnel originated or joined the ascending aorta above the sinus of Valsalva and the sinuses were normal. Furthermore, evidence of the presence of the tunnel appeared during infancy, suggesting that it was present at birth and not the result of a postnatal rupture.An abnormal communication between the aorta and the left ventricle may also be secondary to a rupture of either a congenital or acquired aneurysm of a sinus of Valsalva. Congenital aneurysms usually come to the attention of the physician only after rupture into one of the adjacent cardiac chambers, although the diagnosis prior to rupture can be made by angiocardiography.6 Up to 1961 Sakakibara and Konno7 found 52 well-documented cases of aneurysm of the sinuses of Valsalva with rupture, and in three of these, 564 an aneurysm of the right sinus had ruptured into the left ventricle. The average age of rupture, as ascertained by history and physical examination, of the entire 52 cases was 32 years, and the youngest with rupture into Case Report This white male infant was first seen at the age Circulation, Volume XXXI, April 1965 From the

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