Left ventricular longitudinal strain and strain rate measured by 2-D speckle tracking echocardiography in neonates during whole-body hypothermia.

Abstract

The purpose of the study was to assess changes in cardiac performance in newborn infants with hypoxic-ischemic encephalopathy during therapeutic hypothermia and rewarming with two-dimensional speckle tracking echocardiography. For eight asphyxiated neonates (median birth weight (range): 3038 (2725-3253) g; umbilical artery pH: 6.9 (6.8-7.18) undergoing whole-body hypothermia (33-34°C), left ventricular longitudinal strain and strain rate, as well as heart rate, cardiac output and left ventricular fractional shortening, were determined at four points in time: the start (T1) and end of hypothermia (T2), immediately after rewarming (T3) and the age of 5 to 7 d (T4). Mean (standard deviation) heart rate increased from 93 (12) beats/min at T1 to 133 (12) beats/min at T4 (p < 0.001). Cardiac output was low during hypothermia (T1: 207 [43] mL/kg/min, T2: 240 [70] mL/kg/min) and increased significantly (p < 0.001) afterward (T3: 329 [70] mL/kg/min, T4: 388 [78] mL/kg/min). Left ventricular fractional shortening remained unchanged. Left ventricular global longitudinal peak systolic strain did not differ significantly between hypothermia and rewarming, whereas the systolic strain rate increased from -1.1 (0.3) s(-1) at T1 to -1.8 (0.26) s(-1) at T4 (p = 0.001). Hypothermia affects peak systolic strain rate, heart rate and cardiac output, with complete recovery after rewarming, whereas peak systolic strain and fractional shortening remain stable.

• Authors: Christoph Czernik, Stefanie Rhode, Sven Helfer, Gerd Schmalisch, Christoph Bührer
• Journal: Ultrasound in medicine & biology (Ultrasound Med Biol) Vol. 39 Issue 8 Pg. 1343-9 (Aug 2013) ISSN: 1879-291X [Electronic] England
• PMID: 23743104 (Publication Type: Journal Article)
• Copyright: Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Topics

• Elastic Modulus
• Elasticity Imaging Techniques (methods)
• Female
• Heart Ventricles (diagnostic imaging, physiopathology)
• Humans
• Hypothermia, Induced
• Hypoxia-Ischemia, Brain (diagnostic imaging, physiopathology, therapy)
• Infant, Newborn
• Male
• Treatment Outcome