Featured Research

from universities, journals, and other organizations

An Irregular Heartbeat Makes Exercise Deadly

Date:
August 25, 2006
Source:
Journal of Clinical Investigation
Summary:
Humans lacking the protein cardiac calsequestin (CASQ2) have a normal heartbeat when not exercising, but their heartbeat becomes irregular when they exercise, putting them at risk for sudden death. A new study in mice, by researchers from Vanderbilt University, has now shed light on why the lack of CASQ2 only triggers an irregular, and potentially fatal, heartbeat during exercise.

The results of a study in mice that was conducted by researchers from Vanderbilt University has provided a potential explanation for why the heartbeat of humans lacking the protein cardiac calsequestrin (CASQ2) is irregular, and potentially fatal, only during exercise and not at other times.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a life-threatening disease characterized by an irregular heartbeat during exercise. CPVT can be caused by mutations in the gene encoding CASQ2, which is a Ca2+-binding protein found in the Ca2+ storage facility of the muscle cells of the heart.

Paradoxically, although CASQ2 is thought to have a crucial role in regulating contraction of the heart, individuals lacking both copies of CASQ2 and whose hearts contract relatively normally have been identified. In a study that appears online on August 24 in advance of publication in the September print issue of the Journal of Clinical Investigation, Björn Knollmann and colleagues generated Casq2-deficient mice to help explain this paradox.

Similar to humans lacking CASQ2, Casq2-deficient mice showed normal heart contraction under basal conditions, but both exercise and exposure to catecholamines (which are chemicals such as epinephrine made by the body during exercise and stress) induced an irregular heartbeat. The authors found that the lack of Casq2 was compensated for in several ways, including a substantial increase in the volume of the Ca2+ storage facility in the muscle cells of the heart, such that under basal conditions the heartbeat was regular.

However, when exposed to catecholamines, a lack of Casq2 caused Ca2+ to spontaneously leak from its storage facility and trigger an inappropriate heartbeat.

This study identifies the mechanisms behind the irregular heartbeats caused by a lack of Casq2, and might explain why the hearts of humans lacking CASQ2 beat relatively normally, but can beat irregularly and put these individuals at risk of sudden death when they exercise.


Story Source:

The above story is based on materials provided by Journal of Clinical Investigation. Note: Materials may be edited for content and length.


Cite This Page:

Journal of Clinical Investigation. "An Irregular Heartbeat Makes Exercise Deadly." ScienceDaily. ScienceDaily, 25 August 2006. <www.sciencedaily.com/releases/2006/08/060824224141.htm>.
Journal of Clinical Investigation. (2006, August 25). An Irregular Heartbeat Makes Exercise Deadly. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2006/08/060824224141.htm
Journal of Clinical Investigation. "An Irregular Heartbeat Makes Exercise Deadly." ScienceDaily. www.sciencedaily.com/releases/2006/08/060824224141.htm (accessed September 30, 2014).

Share This



More Health & Medicine News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How 'Yes Means Yes' Defines Sexual Assault

How 'Yes Means Yes' Defines Sexual Assault

Newsy (Sep. 29, 2014) — Aimed at reducing sexual assaults on college campuses, California has adopted a new law changing the standard of consent for sexual activity. Video provided by Newsy
Powered by NewsLook.com
Scientists May Have Found An Early Sign Of Pancreatic Cancer

Scientists May Have Found An Early Sign Of Pancreatic Cancer

Newsy (Sep. 29, 2014) — Researchers looked at 1,500 blood samples and determined people who developed pancreatic cancer had more branched chain amino acids. Video provided by Newsy
Powered by NewsLook.com
Colo. Doctors See Cluster of Enterovirus Cases

Colo. Doctors See Cluster of Enterovirus Cases

AP (Sep. 29, 2014) — Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com
Dr.'s Unsure of Cause of Fast-Spreading Virus

Dr.'s Unsure of Cause of Fast-Spreading Virus

AP (Sep. 29, 2014) — Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins