Sudden Cardiac Arrest: Boosting Chance of Survival

By Mary Jane Dittmar

Sudden cardiac arrest (SCA) has many causes and can strike at any time, as we all know. The medical community has been relentlessly working toward finding ways to increase the chances of survival for patients suffering SCA in the pre-hospital setting. One such initiative is the American Heart Association’s Mission: Lifeline® program, which has recently had added to it a cardiac resuscitation component. The objective is to streamline systems of care for response and treatment to improve SCA survival rates. The program provides public education and support for coordinating emergency medical services providers and hospitals to improve care for patients with cardiac arrest.1 According to the AHA, out-of-hospital cardiac arrest strikes about 382,000 Americans each year, and nearly 90 percent of these patients die.

The Lifeline program was originally introduced in 2007 to improve care for patients with ST-elevation myocardial infarction (STEMI), damage to the heart muscle caused by a blocked blood supply to the heart. Nearly 300,000 people have a STEMI annually. To prevent death, blood flow must immediately be restored, either by surgically opening the blocked vessel or by giving clot-busting medication.2 More than 580 community-based STEMI systems are now registered in Mission: Lifeline, covering more than 60 percent of the U.S. population.3 The AHA recognizes hospitals for quickly and appropriately treating heart attack patients. Ten hospitals have been accredited as of May 23, 2012; more applications are being considered.

“The system of care needed for a person who has a cardiac arrest in the community is much the same as it is for STEMI; many cardiac arrest patients also have STEMI,” explains Christopher B. Granger, M.D., AHA’s chair of Mission: Lifeline Advisory Working Group. That system of care includes the time span beginning with what bystanders do to help the person with SCA and the actions of EMS and hospital personnel to post-hospital care.1

Dr. Granger points out: “We know how to improve survival, but the simple things—like training people to recognize cardiac arrest, call 911, and perform hands-only CPR—are not being done for most victims. Success depends on a coordinated and systematic approach for the community.”1

Dr. Granger, professor of medicine at Duke University Medical Center, in Durham, N.C., reports that “paramedics are making the STEMI diagnosis earlier; patients are being transported or transferred to appropriate hospitals more quickly; and blocked arteries are being opened faster—all translating to more lives saved.”

Graham Nichol, M.D., volunteer for Mission: Lifeline and professor and director at the University of Washington-Harborview Center for Prehospital Emergency Care in Seattle, Washington, notes, “a large variation in survival after out-of-hospital cardiac arrest from one community to the next.” People must recognize possible cardiac arrest, call 911, and begin CPR immediately, he emphasizes. Nichol says in most U.S. communities, about 20 percent of patients who have cardiac arrest have a bystander administer CPR, whereas in communities that are very successful in improving survival rates, like Seattle and parts of Arizona, 40 percent to 50 percent of SCA patients receive bystander CPR. Dr. Nichol noted that care can be improved only if everybody in a community works together.3

Civilians, however, have been hesitant about using automated external defibrillators (AEDs) on SCA patients, even if an AED is available. According to one study published in 2010, more than half of respondents at an Amsterdam train station said they would be unwilling to use an AED during an emergency. Respondents said they did not know how to use the AED or were afraid of causing harm to the patient.3

New technology appears to be helping civilians become more comfortable in responding to emergencies requiring AEDs. In a study by the University of Washington’s Department of Medicine, untrained children proved only slightly slower than trained medical responders in using an AED. The sixth-grade participants were first-time rescuers in a mock SCA emergency; they were able to offer help in an average of 90 seconds.3

John Fiegel, Interim President of the Sudden Cardiac Arrest Association, says, “Creating a culture that understands what an AED is and how it is used will ensure that more lives can be saved.”

The use of AEDs, no doubt, is a crucial topic for community public education programs. These programs should emphasize also the need to maintain the AED units and shuld outline the provedure doing so. The American College of Emergency Physicians found in a 2011 study that dead batteries were responsible for close to 25 percent of AED failures. All AEDs have an active indicator that alerts owners to a low battery. In a new model, a maintenance screen displays the pad and battery expiration dates and the amount of battery life remaining. AED pads also have a finite shelf life. Video prompts can also assist in maintaining units. Visual guides show how to replace batteries and pads and to upgrade software. Digital cards and USB ports make it possible to update AEDs in the field by electronically downloading software. 3

Public education should include also an explanation of the Good Samaritan Law that protects laypersons from liability if injury or death results during an emergency in which a layperson attempts to help the victim; in addition, not having a properly working AED on the premises could also be the basis for a lawsuit by a victim’s family if an SCA patient dies because of the absence of an AED.  Business owners must continually ensure the units are in working order and that staff members are trained in their use. AEDs should be kept in central locations with signage. 3

As new information on SCA is discovered, we must continually update our personal knowledge base. For example, recognizing that a person is having a STEMI will get that patient the type of help (surgical intervention or clot-busting drugs) to restore blood flood as quickly as possible. Keeping someone who suddenly feels ill or becomes unconscious under close medical scrutiny and getting/or performing medical intervention immediately may be a life-saver. If a firefighter complains of not feeling well on the fireground or in the fire station, perhaps it would be wise to stay with that firefighter until he has been thoroughly checked out medically and not allow him to go back to the station or home to rest alone. We are searching for answers to some of the line-of-duty deaths for SCA. We don’t know where we will actually find a clue.

Read on. Below are two other recent findings that can impact sudden cardiac death.

 

Endnotes

  1. “American Heart Association develops program to increase cardiac arrest survival,” Central Florida Cardiology Group, PA, www.cfcg.com; accessed June 4, 2012.
  2. “Systems treating severe heart attacks expanding nationwide,” American Heart Association, www.newsroom.heart.org, accessed May 23, 2012.
  3. “Technology to the Rescue,” Occupational Health & Safety, http://ohsonline.com, accessed May 31, 2012.

 Additional Resources:

www.heart.org/missionlifeline

www.cintas.com (first aid, CRP, AED training)

“QRS complex” on Electrocardiogram

A study published in Circulation online in May found that QRS duration is an independent predictor of the risk of sudden cardiac death (SCD) and may be useful in estimating SCD risk in the general population. “QRS” refers to the electrical waves traveling through the lower chambers (ventricles), shown on the electrocardiogram (ECG) as the “QRS complex.” The study was led by Sudhir Kurl, M.D., a research physician at the University of Eastern Finland in Kuopio. 

SCD was defined as death occurring within an hour after symptoms start or change abruptly, or within 24 hours if there’s no other non-cardiac cause of sudden death. “An essential part of our study is to bring the results to healthcare professionals — including those in preventive medicine — to make them aware that the simple, cheap and widely available ECG may have practical use in SCD risk stratification,” Kurl said.

The study involved 2,049 Finnish men, ages 42 to 60, between March 1984 and December 1989 and tracked them for 19 years. Researchers evaluated their ECG records, heart risk factors, heart disease they developed during the study, whether they died, and the cause of death. The participants were then placed into five categories according to their QRS durations. Among the entire cohort, 156 died from SCD.

Among the study’s significant results were the following:

  • The risk of SCD rose 27 percent for every 10-millisecond (ms) increase in the QRS duration.
  • The larger the QRS increase, the greater the SCD risk.
  • Men with QRS duration longer than 110 ms had 150 percent (or 2.5-fold) higher SCD risk than those with QRS of less than 96 ms, after researchers accounted for such factors as age, a previous heart attack, blood pressure, type 2 diabetes and fitness level.
  • Total deaths from any cause numbered 557. The 156 SCDs were compared with 185 non-sudden deaths from coronary heart disease, a narrowing of the arteries that supply blood to the heart.
  • QRS duration posed a higher risk of SCD than cigarette smoking, poor physical fitness, high systolic blood pressure, body mass index, and C-reactive protein.
  • Only a prior heart attack and type 2 diabetes increased risk of SCD more than QRS duration.

Kurl noted that “QRS duration is one of the strongest risk factors for sudden cardiac death, although left ventricular function was taken into account.” He recommends that “a resting ECG be used to help assess the risk of SCD in particular patients,” particularly people with known cardiovascular disease, cardiovascular risk factors and symptoms, and those who are inactive and plan to begin exercising.

Resource

  1. American Heart Association/American College of Cardiology guidelines for assessing risk in asymptomatic adults.

 

FDA: Zithromax (azithromycin)

The U.S. Food and Drug Administration (FDA) is reviewing the results of the study published in the New England Journal of Medicine  May 17, 2012, which reported a small increase in cardiovascular deaths, and in the risk of death from any cause, in persons treated with a five-day course of azithromycin (Zithromax) compared to persons treated with amoxicillin, ciprofloxacin, or no drug.

Azithromycin, a member of the macrolides class of antibacterial drugs, has been associated with cardiovascular effects–specifically, prolongation of the QT interval. In 2011, FDA reviewed macrolide drug labeling information related to QT interval prolongation and TdP and revised the WARNINGS AND PRECAUTIONS section of the Zmax drug label (azithromycin extended release for oral suspension) in March 2012 to include new information regarding risk for QT interval prolongation. The drug labels for clarithromycin and erythromycin also contain information about QT interval prolongation in the WARNINGS section. FDA is also updating risk information in the drug labels for additional macrolide antibacterial drugs.

Patients taking azithromycin should not stop taking their medicine without talking to their healthcare professional. Healthcare professionals should be aware of the potential for QT interval prolongation and heart arrhythmias when prescribing or administering macrolides. The MedWatch safety alert, including a link to the Drug Safety Communication is at 

http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm304503.htm.

Graphic courtesy of www.photos8.com.  

 

MARY JANE DITTMAR is senior associate editor of Fire Engineering and conference manager of FDIC. Before joining the magazine in January 1991, she served as editor of a trade magazine in the health/nutrition market and held various positions in the educational and medical advertising fields. She has a bachelor’s degree in English/journalism and a master’s degree in communication arts.

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