Incidence and causes of sudden death in college athletes.

Barry Maron et al.
JACC 2014;63:1636-43.

Out of Hospital Cardiac Arrest in Children - Outcomes

J Am Coll Cardiol, 2011; 57:1822-1828, doi:10.1016/j.jacc.2010.11.054
© 2011 by the American College of Cardiology Foundation

Incidence, Causes, and Outcomes of Out-of-Hospital Cardiac Arrest in Children

A Comprehensive, Prospective, Population-Based Study in the Netherlands

Abdennasser Bardai, MD et al.

Email: h.l.tan@amc.uva.nl).

Objectives: This study sought to determine comprehensively the incidence of pediatric out-of-hospital cardiac arrest (OHCA) and its contribution to total pediatric mortality, the causes of pediatric OHCA, and the outcome of resuscitation of pediatric OHCA patients.

Background: There is a paucity of complete studies on incidence, causes, and outcomes of pediatric OHCA.

Methods: In this prospective, population-based study, OHCA victims younger than age 21 years in 1 province of the Netherlands were registered through both emergency medical services and coroners over a period of 4.3 years. Death certificate data on total pediatric mortality, survival status, and neurological outcome at hospital discharge also were obtained.

Results: With a total mortality of 923 during the study period and 233 victims of OHCA (including 221 who died and 12 who survived), OHCA caused 24% (221 of 923) of total pediatric mortality. Natural causes of OHCA amounted to 115 (49%) cases, with cardiac causes being most prevalent (n = 90, 39%). The incidence of pediatric OHCA was 9.0 per 100,000 pediatric person-years (95% confidence interval: 7.8 to 10.3), whereas the incidence of pediatric OHCA from cardiac causes was 3.2 (95% confidence interval: 2.5 to 3.9). Of 51 resuscitated patients, 12 (24%) survived; among survivors, 10 (83%) had a neurologically intact outcome.

Conclusions: Out-of-hospital cardiac arrest accounts for a significant proportion of pediatric mortality, and cardiac causes are the most prevalent causes of OHCA. The vast majority of OHCA survivors have a neurologically intact outcome.

Editorial:
J Am Coll Cardiol, 2011; 57:1829-1830, doi:10.1016/j.jacc.2010.11.055

Improved Outcomes for Cardiac Arrest in Children

Share the Baton With the Bystander*

Sumeet S. Chugh, MD*
Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California

* Reprint requests and correspondence: Dr. Sumeet S. Chugh, The Heart Institute, 5702 South Tower, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, California 90048 (Email: sumeet.chugh@cshs.org).

Key Words: bystander • cardiac arrest • death • pediatric • population • sudden • survival

We continue to grapple with the complexities of preventing and resuscitating out-of-hospital cardiac arrests (OHCAs). Of these, cardiac arrests among children clearly have the most devastating effect on communities. The study from Bardai et al. (1) based in North Holland, the Netherlands, is an important investigation with some caveats and several lessons that merit some discussion.
This was a prospective study in a community of 2.4 million people, with 588,389 residents younger than 21 years of age. It is important to recognize that the manner in which Bardai et al. (1) presented their data tends to overestimate the actual incidence of pediatric OHCA. Their definition of OHCA was very broad and included natural causes (cardiac and noncardiac) as well as all unnatural causes of OHCA, such as traffic accidents and violent trauma. Another reason for possible overestimation relates to their inclusion of subjects 20 years of age or younger (the 18- to 20-year age group represented 25% of total OHCAs). Nonetheless, their findings indicate that similar to adults, there is likely to be geographic variation in the annual incidence of pediatric OHCA. Even if we focus on the subgroup of natural OHCA of likely cardiac cause, the annual incidence ranges from 3.2 per 100,000 children in North Holland, the Netherlands, to 7.5 per 100,000 in Portland, Oregon (2). For the purpose of reporting, it is helpful to make a clear separation between OHCA resulting from natural causes versus that resulting from unnatural causes, because the approach to prevention is distinctly different for each category. Although childhood cardiac arrests invariably are the most devastating of the OHCAs, fortunately, they are relatively uncommon, representing 1.3% and 2.8% of all OHCAs in North Holland, the Netherlands, and Portland, Oregon, respectively.

Similar to adults, the vast majority of pediatric OHCAs (78% in the North Holland study) are related to cardiac causes. However, the age distribution of North Holland pediatric OHCAs in this subgroup is distinct from that of earlier reports. The significantly lower proportion of infants (39%) is a departure from the expected highest rates in the younger than 1 year age group compared with older pediatric age groups, and the authors point us to published data that suggests a 5.7-fold higher incidence of sudden infant death syndrome (SIDS) in the United States compared with the Netherlands (3). Because they do not provide us with any information regarding what proportion of infants had a diagnosis of SIDS, we have to assume that the rates of SIDS are lower compared with those of other communities. Although successful SIDS prevention through education and modification of behavior and societal or cultural practices is a well-established strategy, the North Holland findings could indicate that there is significant room for improvement in prevention of SIDS in other parts of the world.

The most striking findings of the North Holland study relate to the outcome of resuscitated pediatric OHCAs, both in terms of survival to hospital discharge as well as neurologic recovery. The overall rate of survival to hospital discharge was 24% (12 of 51), and the overall rate of neurologic recovery was 83%. When taken in the context of the existing literature (6.4% survival in a recent large North American experience [4]), this is an enviable rate of survival and neurologic recovery for pediatric OHCAs. OHCAs with ventricular tachycardia or ventricular fibrillation, as opposed to pulseless electrical activity or asystole, are significantly more likely to survive, and Bardai et al. (1) report high rates of ventricular tachycardia or ventricular fibrillation (36% overall, with 83% among adolescents). However, these rates do not seem to be explained by the somewhat modest response times that are in the range of 11 to 12 min. It is likely, therefore, that this favorable outcome is attributable to the high rates of witnessed collapse, bystander cardiopulmonary resuscitation, and use of automated external defibrillators. Although there are other factors, such as population density and overall education level of residents, that likely contribute to the survival advantage enjoyed by North Holland pediatric residents, this solid outcome clearly reflects successful bystander education in a well-deployed emergency medical response system.

Bardai et al. (1) need to be congratulated for their impressive work in a sizable community. Although their community may have some specific characteristics that are not transferable to other regions, the excellent survival and neurologic recovery rates are unmistakable and demonstrate the feasibility of attaining better outcomes for pediatric OHCA, especially by increasing awareness within the community. Improved bystander CPR, as well as use of automated external defibrillators, are likely to be of particular benefit for resuscitation in children. Simultaneously, because most naturally occurring pediatric sudden deaths are likely to be cardiac, we also must continue to focus our efforts on prevention. Although SIDS is acknowledged to be a complex disorder with multiple causes, major inroads have also been made by focused community-based educational interventions (3). In addition, the younger the age, the higher the likelihood of a genetic cause. A renewed emphasis needs to be placed on community health care providers obtaining detailed family histories with appropriate referral for genetic screening and counseling. In the event of unexplained sudden deaths, a molecular autopsy (5,6) should become part of the community forensic investigation as a critical means of enhancing prevention for family members who are left behind.




Footnotes

Dr. Chugh is the Pauline and Harold Price Professor of Cardiac Electrophysiology at the Cedars-Sinai Heart Institute, Los Angeles, California; there are no other relationships to disclose.

* Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.


References

1. Bardai A, Berdowski J, van der Werf C, et al. Incidence, causes, and outcomes of out-of-hospital cardiac arrest in children: a comprehensive, prospective, population-based study in the Netherlands J Am Coll Cardiol 2011;57:1822-1828.[Abstract/Free Full Text]
2. Chugh SS, Reinier K, Balaji S, et al. Population-based analysis of sudden death in children: the Oregon Sudden Unexpected Death Study Heart Rhythm 2009;6:1618-1622.[CrossRef][Web of Science][Medline]
3. Moon RY, Horne RS, Hauck FR. Sudden infant death syndrome Lancet 2007;370:1578-1587.[CrossRef][Web of Science][Medline]
4. Atkins DL, Everson-Stewart S, Sears GK, et al. Epidemiology and outcomes from out-of-hospital cardiac arrest in children: the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest Circulation 2009;119:1484-1491.[Abstract/Free Full Text]
5. Chugh SS, Senashova O, Watts A, et al. Postmortem molecular screening in unexplained sudden death J Am Coll Cardiol 2004;43:1625-1629.[Abstract/Free Full Text]
6. Tan HL, Hofman N, van Langen IM, van der Wal AC, Wilde AA. Sudden unexplained death: heritability and diagnostic yield of cardiological and genetic examination in surviving relatives Circulation 2005;112:207-213.[Abstract/Free Full Text]

T wave components in LQTS 1

• CIRCEP.110.958827Published online before print April 21, 2011
• Original Article

Detection of Extra-Components of T Wave by Independent Component Analysis in Congenital Long QT Syndrome

1. Hitoshi Horigome,
2. Yasuhiro Ishikawa,
3. Junko Shiono,
4. Mari Iwamoto,
5. Naokata Sumitomo and
6. Masao Yoshinaga

1. ¹ University of Tsukuba, Tsukuba, Ibaraki, Japan;
2. ² Ishikawa Clinic & Toyohashi University of Technology, Toyohashi, Aichi, Japan;
3. ³ Ibaraki Children's Hospital, Mito, Ibaraki, Japan;
4. ⁴ Yokohama City University, Yokohama, Japan;
5. ⁵ Nihon University, School of Medicine, Tokyo, Japan;
6. ⁶ National Hospital Organization Kagoshima Medical Center, Kagoshima, Jap
   hhorigom@md.tsukuba.ac.jp

Abstract

Background—The main EKG criteria for the diagnosis of long QT syndrome (LQTS) include abnormal T wave morphology as well as prolonged QT interval. The T wave in LQTS probably includes additional components of myocardial repolarization process, which is derived from aberrant ion currents. We investigated whether independent component analysis (ICA) can extract such abnormal repolarization component.

Methods and Results—Digital EKG data were obtained as time series from 10 channels using 20 surface electrodes in 22 patients with genetically-confirmed LQTS type 1 (LQT1) and 30 normal subjects. In each case, T wave area was analyzed by radical ICA after noise reduction by the wavelet thresholding method. Furthermore, inverse ICA was applied to determine the origin of each independent component (IC). Radical ICA revealed that a T-wave consisted of four basic ICs in all control subjects, whereas five or more (mostly 6) ICs were identified in all 22 cases of LQT1. The extra ICs, which were not evident in normal subjects, were assumed to contribute to the formation of abnormal T-wave morphology. The extra ICs were identified even in those patients with normal QTc values and those taking β-blockers. Inverse ICA indicated that the additional ICs originate predominantly from the late phase of the T wave of the left ventricle.

Conclusions—Extra ICs appear during repolarization in all LQT1 patients but not in normal subjects. ICA is a potentially useful multivariate statistical method to differentiate LQT1 patients from normal subjects.

ECG for Sports Screening

A pilot study of the feasibility of heart screening for sudden cardiac arrest in healthy children
Victoria L. Vetter et al.

American Heart Journal. Available online 12 March 2011

Background
In children, sudden cardiac arrest (SCA) is associated with structural and electrical cardiac abnormalities. No studies have systematically screened healthy school children in the United States for conditions leading to SCA to identify those at risk.
Methods
From June 2006 to June 2007, we screened 400 healthy 5- to 19-year-olds (11.8 ± 3.9 years) in clinical offices at The Children's Hospital of Philadelphia using a medical and family history questionnaire, weight, height, blood pressure, heart rate, cardiac examination, electrocardiogram (ECG), and echocardiogram (ECHO). Our goals were to determine the feasibility of adding an ECG to history and physical examination and to identify a methodology to be used in a larger multicenter study. A secondary objective was to compare identification of cardiovascular abnormalities by history and physical examination, ECG, and ECHO.
Results
Previously undiagnosed cardiac abnormalities were found in 23 subjects (5.8%); an additional 20 (5%) had hypertension. Potentially serious cardiac conditions were identified in 10 subjects (2.5%); 7 were suspected or identified by ECG and 3 more only by ECHO. Only 1 of the 10 had symptoms (previously dismissed); none had a positive family history.

Referral bias - is an important issue in this study. (Community pediatricians were told to refer children whom they thought were healthy and did not have any cardiac issues).

EKG screening for Pre-participation Sports Screening (Israel)

J Am Coll Cardiol, 2011; 57:1291-1296

CLINICAL RESEARCH: PRE-PARTICIPATION ATHLETIC SCREENING

Mandatory Electrocardiographic Screening of Athletes to Reduce Their Risk for Sudden Death. Proven Fact or Wishful Thinking?

Arie Steinvil, MD et al.
Tel Aviv University, Tel-Aviv, Israel

Objectives: The purpose of this study was to determine if pre-participation screening of athletes with a strategy including resting and exercise electrocardiography (ECG) reduces their risk for sudden death.

Background: An increasing number of countries mandate pre-participation ECG screening of athletes for the prevention of sudden death. However, the evidence showing that such a strategy actually reduces the risk of sudden death in athletes is limited. We therefore analyzed the impact of the National Sport Law enacted in Israel in 1997—which mandates screening of all athletes with resting ECG and exercise testing—on the incidence of sudden death among competitive athletes.

Methods: We conducted a systematic search of the 2 main newspapers in Israel to determine the yearly number of cardiac arrest events among competitive athletes. The size of the population at risk was retrieved from the Israel Sport Authority and was extrapolated to the changes in population size over time.

Results: There were 24 documented events of sudden death or cardiac arrest events among competitive athletes during the years 1985 through 2009. Eleven occurred before the 1997 legislation and 13 occurred after it. The average yearly incidence of sudden death or cardiac arrest events was 2.6 events per 100,000 athlete-years. The respective averaged yearly incidence during the decade before and the decade after the 1997 legislation was 2.54 and 2.66 events per 100,000 person years, respectively (p = 0.88).

Conclusions: The incidence of sudden death of athletes in our study is within the range reported by others. However, mandatory ECG screening of athletes had no apparent effect on their risk for cardiac arrest.