Maturational changes in cardiac muscle myosin adenosine triphosphatase activity relative to hemodynamic alterations in newborn lambs

To determine the influence of heart rate (HR) on systolic time intervals (STI) in neonates, serial measurements of right ventricular (RVSTI) and left ventricular systolic time intervals (LVSTI) were made on 30 healthy term newborn infants at age 4-8 h, 24-30 h, eight days, and four weeks. STI was related to HR and age. Age-related changes were similar to previously reported results. The preejection periods (RPEP and LPEP) significantly shortened with increasing age, whereas the right and left ventricular ejection times (RVET and LVET) were unrelated to age. RPEP was unrelated to HR, but tended to be prolonged in restless infants. With increasing HR, RVET decreased and RPEP/RVET increased in all age groups, but less at four weeks. A rise in HR of 50/min resulted in an increase of RPEP/RVET by 26% of the mean value at age 4-8 h and by 20% at four weeks. In 14 infants, RVSTI was recorded during a change in HR. In all these infants, RPEP and RPEP/RVET increased with increasing HR. We conclude that HR-related changes of RVSTI in neonates are different from those in older subjects. It should be considered that in neonates elevated values of RPEP/RVET, suggesting increased pulmonary vascular resistance, may be caused by high HR and unrest.

show abstract

Heart rate and systolic time intervals in healthy newborn infants: Longitudinal study

Lindner

Döhlemann

Schneider

et al. 1985

Pediatr Cardiol

View full text Add to dashboard Cite

show abstract

Relation of myosin isozymes to the heart as a pump

Wikman‐Coffelt

Parmley

Mason

1982

American Heart Journal

View full text Add to dashboard Cite

Maturational changes in myocardial pump performance in newborn lambs

Riemenschneider

Allen

Mason

1986

American Heart Journal

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Maturational changes in cardiac muscle myosin adenosine triphosphatase activity relative to hemodynamic alterations in newborn lambs

Cited by 7 publications

References 28 publications

Heart rate and systolic time intervals in healthy newborn infants: Longitudinal study

Heart rate and systolic time intervals in healthy newborn infants: Longitudinal study

Relation of myosin isozymes to the heart as a pump

Maturational changes in myocardial pump performance in newborn lambs

Contact Info

Product

Resources

About