The team was not able to collect tocodynamometry, intrauterine pressure, and electrohysterography data simultaneously. In paired comparisons, "tocodynamometry identified 248 contractions compared with 336 by electrohysterography, whereas intrauterine pressure catheter monitoring identified 319 contractions," the investigators report.

The electrohysterogram findings correlated better with those of the intrauterine pressure catheter, than with tocodynamometry, Euliano's team found.

However, the physicians point out that intrauterine pressure catheter placement is an invasive procedure, increasing the risk of infection, perforation of the uterus, and rupture of the placenta.

The investigators conclude that electrohysterography may provide a better way to noninvasively monitor uterine activity, especially in obese women.

"There is no specific degree" of obesity for which the clinician would opt for intrauterine pressure monitoring, Euliano told Reuters Health. "We first try external monitoring, and only use intrauterine pressure when that is inadequate" or if there is another reason to use it.

SOURCE: Obstetrics and Gynecology May, 2007.

Copyright © 2007 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.

iPods may interfere with pacemakers

Last Updated: 2007-05-10 16:37:06 -0400 (Reuters Health)

By Megan Rauscher

NEW YORK (Reuters Health) - Apple iPod MP3 music players may interfere with the functioning of implanted pacemakers, according to research reported Thursday at the Heart Rhythm Society's 28th annual scientific sessions underway in Denver, Colorado.

"Our observations are disconcerting because implantable pacemakers have become commonplace worldwide and the iPod has become a ubiquitous personal digital entertainment device," the Michigan-based study team writes in a meeting abstract.

Pacemaker malfunction caused by cell phones is well described. In their study, Dr. Krit Jongnarangsin of the University of Michigan, Ann Arbor and colleagues looked at the effect of four different iPod models (third generation, photo, video and Nano iPods) on implantable pacemaker function in 100 patients.

A technician monitored electrocardiographs while each iPod was held near the chest for 5 to 10 seconds in the on and off position.

The iPods, when held 2 inches from the patients' chest and as far as 18 inches, "interfered with pacemaker function in about one third of patients," Jongnarangsin noted in a telephone interview with Reuters Health.

Pacemaker oversensing - incorrectly sensing a cardiac event -- was seen in 19 percent of patients.

Telemetry interference -- defined as any other interference that did not affect pacing function and was not detected by pacemaker interrogation -- occurred in 32 percent, and pacemaker inhibition in 1 percent.

Oversensing and telemetry interference occurred more often with third generation iPods and the photo iPod than with the video and Nano iPod.

The observed iPod interference did not cause any clinical symptoms. "However, in one patient the iPod transiently inhibited pacemaker function," Jongnarangsin pointed out.

There is a concern, he added, that iPod interference might lead to an incorrect diagnosis of abnormal heart rhythm. "If we don't take into account that the patient has an iPod close to the pacemaker, we may assume that the patient has an abnormal heart rate rhythm," Jongnarangsin said.

"We need more information and more studies on iPod interference in pacemaker function," he concluded.

Copyright © 2007 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.