ORIGINAL C O N T R I B U T I O N
cardiac arrest, epidemiology
The Epidemiology of Cardiac Arrest in Young Adults
Fromthe School of Medicine* andDepartment of Medicine,t University of Washington; a n d the Centerfor Evaluation of Emergency Medical Services,~: Emergency Medical Services Division, Seattle-King County Department of Public Health, Seattle, Washington.
Daniel J Safranek, MD* Mickey S Eisenberg, MD, PhD~t Mary Pat Larsent
Receivedfor publication October12, 1990~ Revision received January 20, 1992. Acceptedfor publication February 17, 1992.
Study objective: Todescribe the epidemiology of cardiac arrest in young adults and to determine if there are characteristics unique to this group in terms of etiology, rhythm, and outcome. Design: Retrospective, case review. Setting:
King County, Washington.
Type of participants: All out-of-hospital victims of cardiac arrest who received emergency aid. Measurements: The etiology, cardiac rhythm, and outcome were identified for each case. Main results: During the 13-year period from 1976 to 1989, there were 8,054 cardiac arrests; 252 of these were among young adults 18 to 35 years of age. Of those 252 cases, 61 (24%)were caused by ischemic heart disease, and 60 (24%) were caused by overdose. Asystole was the most common rhythm (48%), followed by ventricular fibrillation or tachycardia (31%). Long-term survival following these rhythms was 4% and 28%, respectively. In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults. There were no unique characteristics specific to young adults. Long-term survival is dependent more on rhythm than on age. Conclusion: In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults. [Safranek DJ, Eisenberg MS, Larsen MP: The epidemiology of cardiac arrest in young adults. Ann EmergMed September 1992;21:1102-1106.]
SEPTEMBER1992 21:9
ANNALS OF EMERGENCY MEDICINE
1 1 02/ 8 1
CARDIAC ARREST Safranek, Eisenberg & Larsen
INTRODUCTION Out-of-hospital cardiac arrests in adults and children are dramatically different in terms of etiology and likelihood of resuscitation. 1,2 Most cardiac arrests in adults are caused by cardiovascular disease; in children the most common cause of out-of-hospital cardiac arrest is sudden infant death syn-drome. Although several studies describe cardiac arrest in patients u n d e r age 40, no study excludes the pediatric population and focuses specifically on young adults.3, 4 Are the etiologies of cardiac arrest and likelihood of resuscitation different than those of older people and children? What are the implications of these differences to emergency medical services (EMS) systems? The purposes of this study were to describe the epidemiology of cardiac arrest and resuscitation in young adults 18 to 35 years of age and to determine if there are unique characteristics of cardiac arrests in this age group compared with older adults and children.
Figure. Etiology of cardiac arrest Cardiac: Ischemic heart disease (7) 2% Cardiac: Ofh~r (17~ 5% Dro~
y (28) 8% rdose (5) 1%
Other (60) 17%
Sudden infant death syndrome (182) 62%
M A T E R I A L S AND M E T H O D S The study area was s u b u r b a n King County, Washington, which is adjacent to the city of Seattle. The area, 460 square miles, includes 16 incorporated cities, with a population of 900,000. Age and sex distributions throughout the area are similar. Approximately 25% of the population is between 18 and \ 35 years of age; 98% of the population is white, and most earn middle-class incomes, except in the more affluent communities east of Seattle. The study was a retrospective Case review using data collected as part of an ongoing cardiac arrest surveillance system. The study incorporated all cardiac arrests of n o n t r a u matic etiology for which EMS personnel attempted cardiac resuscitation between April 1, 1976, and December 31, 1989. A case was defined as an individual with lack of pulse and blood pressure, confirmed by an emergency medical technician (EMT) or a paramedic, who received CPR. We studied individuals 18 to 35 years of age and compared this group with those less than 18 and those more than 35 years old. For the first 17 months of the study, only basic EMT services were available in a portion of the study area, while the remainder had both EMT and paramedic services in a layered response. I n later years, all areas had layered response. Thus, the majority of cases were treated with both EMT and paramedic services. The primary surveillance tool was the King County EMS incident form, completed by all 43 fire departments and all six paramedic programs in the study area. Identifying information was obtained for each case. In addition, information on cardiac rhythm was obtained. In most instances this was obtained by the paramedics, usually arriving at the scene within eight to ten minutes of the call. Other information routinely collected included whether the cardiac arrest was witnessed directly, the individual initiating CPR, the estimated time from collapse to initiation of CPR, and the estimated
8 2 / 1 1 0 3
0 - 17 Years
schernic heart e (61) 24%
Drowning (22) 9%
Other(43)" ]tory (24) 10%
Cardiac: Other (42) 17% 18 - 35 Years
Drowning and overdose (52) 1%
]tory (431) 6%
]rdiac: Other (266) 4%
Cardiac: Ischemic heart disease (5,706) 81% 36 + Years
A N N A L S OF EMERGENCY M E D I C I N E
21:9
SEPTEMBER 1992
CARDIAC ARREST Safranek, Eisenberg & Larsen
time from collapse to initiation of advanced cardiac life support. The time from collapse to initiation of CPR and advanced cardiac life support was estimated only for witnessed arrests on the basis of incident reports and telephone interviews with emergency personnel and bystanders. The etiolofor the cardiac arrest was determined from autopsy, hospital records, and incident reports. Younger patients were more likely to have had an autopsy. The autopsy rate was 81% for the 0- to 17-year-olds, 75% for the 18- to 35-year01ds, and 16% for the age 36-and-older group. Patients with cardiac arrest from motor vehicle accidents or other t r a u m a including traumatic suicides were excluded because we wished to focus on medical etiologies for cardiac arrest. Statistical differences were determined using the Z2 test. RESULTS
During the study period, 8,054 cardiac arrests met the case definition; 252 (3%) were among individuals 18 to 35 years of age, and 353 (4%) were among individuals 0 to 17 years of age. The other 7,449 (93%) cases were among individuals 36 and older. The most common etiology in the 18- to 35-year-old group was ischemic heart disease, accounting for 61 (24%) cardiac arrests. The second most common etiology was overdose, causing 60 (24%) cardiac arrests. Among the 0- to 17-yearolds, the most common etiology was sudden infant death syndrome, accounting for 182 (52%) cardiac arrests. The second most common etiology was drowning, causing 54 (15%) cardiac arrests. In the 36-and-over age group, the most common etiology was ischemic heart disease, accounting for 5,705 (81%) of all cardiac arrests. The second most common etiology was respiratory, causing 431 (6%) cardiac arrests. Etiologies for the cardiac arrests in the three groups are shown (Figure). ~The other cardiac category included congenital cardiac disorders, rheumatic heart disease, aortic valve disease, and cardiomyopathies. I n the 0- to 17-year-old age group, congenital heart disease was the most common other cardiac etiology. I n the 18-to-35 and 36-and-older age groups, valvular disease and cardiomyopathies were the most common. ECG rhythm interpretation was available in 92% of patients. The most common rhythm in the 18- to 35-year-old age group was asystole, accounting for 48% of all recorded rhythms. The second most common rhythm was ventricular fibrillation (31%). Among the 0- to 17-year-olds, the most Table 1. ECG rhythm associated with cardiac arrest: All etiologies
Rhythm Asystole Idioventricular Ventricular fibrillation/tachycardia Other
% 0-17 80 8 6 6
Age (yr) % 18-35 48 11 31 10
SEPTEMBER 1992 21:9 ANNALSOF EMERGENCYMEDICINE
% 36+ 33 9 46 11
common rhythm was asystole, accounting for 80% of all recorded rhythms. The second most common rhythm was idioventricular (8%). In the 36-and-over age group, the most common rhythm was ventricular fibrillation, accounting for 46% of all recorded rhythms. The second most common rhythm was asystole (33%). The rhythms recorded for the three age groups are listed (Table 1). The other category included nodal rhythms, various heart blocks, sinus bradycardia~ normal sinus, and sinus tachycardia. Survival by etiology is shown (Table 2). In the 0-to-17 group, there were no successful resuscitations in patients with apparent sudden infant death syndrome. In the 18-to-35 age range, 26% of patients with ischemic heart disease as the etiology of the arrest survived, while 18% survived in the 36and-over group (P = NS). Information on survival by first-recorded rhythm is shown (Table 3). The highest rates of survival in all age groups were seen when the first recorded rhythm was ventricular fibrillation or pulseless ventricular tachycardia. When the rhythm was asystole, all groups had a poor survival. Patients with witnessed arrests whose first recorded rhythm is ventricular fibrillation or ventricular tachycardia have better rates of resuscitation and long-term survival compared with patients without these characteristics.5 The 0-to-17 age group is excluded because there were insufficient cases in this category. The long-term survival for witnessed ventricular fibrillation in the 18-to-35 age group was 39%; in the 36-and-over age group, 34% survived (P = NS). For patients with witnessed arrest in rhythms other than ventricular fibrillation, the long-term survival in the 18- to 35-yearold age group was 20%; in the 36-and-over age group, 9% survived. DISCUSSION
The etiologies of cardiac arrest in young adults were somewhat different from those of children or older adults. There is less ischemic heart disease in this age group, and cardiomyopathies are proportionally more prevalent. In their report on prehospital sudden death in young adults, Raymond Table 2. Long-term survival by etiology
Etiology
0-17 No. %
Cardiac:lschemic heart disease Cardiac: Other Respiratory Overdose Drowning Sudden infant death syndrome Other
1 0 6 I 14 0 8
Total for all etiologies
30
14 0 21 20 26 0 13
8.5
Age (yr) 18-35 No. % 16 6 3 t0 6 O 10
26 14 13 17 27 0 23
45 17.9
36+ No. % 1,052 49 37 6 2
18 18 9 17 13
O O 18 3 1,164 16.5
1104/ 83
CARDIAC ARREST
Safranek, Eisenberg & Larsen
and colleagues reported a marked increase in coronary artery disease after the age of 35. They also found that cardiac disease not of coronary artery etiology was the predominate cause of sudden death u n d e r the age of 35.6 We found that the proportion of arrests caused by overdose is higher in the young adults than in either of the other groups. Mittleman and colleague reported the average age of cocaineassociated death to be 29 years. 7 Young adults were more likely to be in asystole and less likely to be in ventricular fibrillation or tachycardia than the older adults. The increase in asystole may be a result of the greater frequency of unwitnessed cases among young adults (49%) compared with older adults (37%). It may also be caused by the different mix of etiologies seen in this group. The young-adult group represents a transition in terms of age, etiology, and rhythm between the children and older adult groups. The 0- to 17-year-olds have a 7% incidence of cardiac arrests caused by heart disease, while the 18- to 35-year-olds and 36-years-and-older age groups had a 41% and 85% incidence, respectively. The ECG rhythms associated with cardiac arrests showed a similar progression. Ventricular fibrillation and tachycardia were seen in 6% of the arrests in children, while they accounted for 31% of arrests in Young adults and 46% of arrests in older adults. Although the incidences of particular rhythms were markedly different between age groups, the long-term survival based on these rhythms was similar. Survival from asystole was lbw in all age groups. The survival following ventricular fibrillation and tachycardia was nearly identical in all ages. Survival rates for children, young adults, and older adults were 25%, 28%, and 29%, respectively. These survival rates are comparable with the 23% overall survival reported by Clinton and colleagues in patients i to 40 years of age. For patients with a witnessed arrest of cardiac etiology where the first recorded rhythm was ventricular fibrillation or tachycardia, the survival rate was 39% for young adults and 34% for older adults. There appear to be no characteristic s unique to the youngadult group. Although there was no statistically significant increased survival in young adults following cardiac arrest, there was a trend toward increased survival in arrests of cardiac etiology and more specifically in witnessed arrests of cardiac etiology where the first recorded rhythm was ven-
tricular fibrillation or tachycardia. This increased survival may be a result of the overall better health of young adults and the likelihood that their heart disease is their only significant medical illness. This study had several limitations. Our surveillance system identified patients with cardiac arrest who received prehospital emergency medical care. The Surveillance system did not identify patients who died in the community without a resuscitation attempt. We specifically excluded traumatic deaths, wishing to focus on medical etiologies of cardiac arrest. Hence, the study does not define the epidemiology of death in young adults, but rather describes patients with nontraumatic cardiac arrests who receive CPR from emergency personnel. There was some imprecision in categorizing etiology of cardiac arrests because not all patients had an autopsy, although the younger patients were more likely than the older adults to have had an autopsy. There also was no mechanism to measure comorbidity such as underlying congestive heart failure, which would be a predictor of poor outcome. What are the implications of this survey for prehospital care of cardiac arrest? The young-adult group has a low incidence of cardiac arrest, less than children and older adults. Young adults are a very heterogeneous group in terms of the etiology of cardiac arrests. They show characteristics of both the younger and older populations. Although the incidence of arrests caused by ischemic heart disease is much less than in the older adults, there are a significant n u m b e r of cases of cardiac etiology with vcntricular fibrillation or tachycardia as the first recorded rhythm. The likelihood of resuscitation is very high for these rhythms, as it is in older adults. CONCLUSION
In terms of etiology and rhythm, young adults aged 18 to 35 appear to be a transitional group linking children and olderadult groups. There seem to be no characteristics unique to the young-adult population in terms of cardiac arrest. Survival following cardiac arrest was best predicted by first recorded rhythm and not the age of the victim.
Table 3.
Long-term survival by ECG rhythm Age (yr) Rhythm
0-17 No. %
18-35 No. %
36+ No. %
Asystole Idioventricular Ventricularfibrillation/tachycardia Other
10 4 3 11 5 25 , 11 55
5 4 3 11 21 28 13 52
42 2 36 6 927 29 145 18
8 4/ 1 1 0 5
ANNALS OF EMERGENCYMEDICINE 21:9 SEPTEMBER1992
~! CARDIAC ARREST
Safranek, Eisenberg & Larsen
REFERENCES I, Eisenberg MS, Bergner L, Hallstrom A: Epidemiology of cardiac arrest and resuscitation in a suburban community. JACEP1979;8:2-5. 2,Eisenberg MS, Bergner L, Hallstrom A: Epidemiology of cardiac arrest and resuscitation in children. Ann Emerg Med 1983;12:31-33. 3,ClintonJE, McGill J, Irwin G, et al: Cardiac arrest under age 40: Etiology and prognosis.Ann Emerg Med1984;13:1011-1014.
Address for reprints: Mickey Eisenberg, MD Center for Evaluation of Emergency Medical Services Emergency Medical Services Division 110 Prefontaine Place South, Suite 500 Seattle, Washington 98104
4,Ng AMY, Clinton JE, Peterson G: Nontraumatic prehospital cardiac arrest ages 1-39 years.Am J Emerg Meal 1990;8:87-91. 5,Eisenberg MS, Hallstrom A, Bergner L: The ACLS score. JAMA 1981;246:40-52. 6.RaymondJR, van den Berg EK, Knapp M J: Nontraumatic prehospital death in young adults.Arch Intern Med 1988;148:303-308. 7.Mittleman RE, Wetli CV: Death caused by recreational cocaine use. JAMA 1984;252:1889- 1893.
SEPTEMBER1992
21:9
ANNALS OF EMERGENCY MEDICINE
1106/85
cardiac arrest, epidemiology
The Epidemiology of Cardiac Arrest in Young Adults
Fromthe School of Medicine* andDepartment of Medicine,t University of Washington; a n d the Centerfor Evaluation of Emergency Medical Services,~: Emergency Medical Services Division, Seattle-King County Department of Public Health, Seattle, Washington.
Daniel J Safranek, MD* Mickey S Eisenberg, MD, PhD~t Mary Pat Larsent
Receivedfor publication October12, 1990~ Revision received January 20, 1992. Acceptedfor publication February 17, 1992.
Study objective: Todescribe the epidemiology of cardiac arrest in young adults and to determine if there are characteristics unique to this group in terms of etiology, rhythm, and outcome. Design: Retrospective, case review. Setting:
King County, Washington.
Type of participants: All out-of-hospital victims of cardiac arrest who received emergency aid. Measurements: The etiology, cardiac rhythm, and outcome were identified for each case. Main results: During the 13-year period from 1976 to 1989, there were 8,054 cardiac arrests; 252 of these were among young adults 18 to 35 years of age. Of those 252 cases, 61 (24%)were caused by ischemic heart disease, and 60 (24%) were caused by overdose. Asystole was the most common rhythm (48%), followed by ventricular fibrillation or tachycardia (31%). Long-term survival following these rhythms was 4% and 28%, respectively. In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults. There were no unique characteristics specific to young adults. Long-term survival is dependent more on rhythm than on age. Conclusion: In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults. [Safranek DJ, Eisenberg MS, Larsen MP: The epidemiology of cardiac arrest in young adults. Ann EmergMed September 1992;21:1102-1106.]
SEPTEMBER1992 21:9
ANNALS OF EMERGENCY MEDICINE
1 1 02/ 8 1
CARDIAC ARREST Safranek, Eisenberg & Larsen
INTRODUCTION Out-of-hospital cardiac arrests in adults and children are dramatically different in terms of etiology and likelihood of resuscitation. 1,2 Most cardiac arrests in adults are caused by cardiovascular disease; in children the most common cause of out-of-hospital cardiac arrest is sudden infant death syn-drome. Although several studies describe cardiac arrest in patients u n d e r age 40, no study excludes the pediatric population and focuses specifically on young adults.3, 4 Are the etiologies of cardiac arrest and likelihood of resuscitation different than those of older people and children? What are the implications of these differences to emergency medical services (EMS) systems? The purposes of this study were to describe the epidemiology of cardiac arrest and resuscitation in young adults 18 to 35 years of age and to determine if there are unique characteristics of cardiac arrests in this age group compared with older adults and children.
Figure. Etiology of cardiac arrest Cardiac: Ischemic heart disease (7) 2% Cardiac: Ofh~r (17~ 5% Dro~
y (28) 8% rdose (5) 1%
Other (60) 17%
Sudden infant death syndrome (182) 62%
M A T E R I A L S AND M E T H O D S The study area was s u b u r b a n King County, Washington, which is adjacent to the city of Seattle. The area, 460 square miles, includes 16 incorporated cities, with a population of 900,000. Age and sex distributions throughout the area are similar. Approximately 25% of the population is between 18 and \ 35 years of age; 98% of the population is white, and most earn middle-class incomes, except in the more affluent communities east of Seattle. The study was a retrospective Case review using data collected as part of an ongoing cardiac arrest surveillance system. The study incorporated all cardiac arrests of n o n t r a u matic etiology for which EMS personnel attempted cardiac resuscitation between April 1, 1976, and December 31, 1989. A case was defined as an individual with lack of pulse and blood pressure, confirmed by an emergency medical technician (EMT) or a paramedic, who received CPR. We studied individuals 18 to 35 years of age and compared this group with those less than 18 and those more than 35 years old. For the first 17 months of the study, only basic EMT services were available in a portion of the study area, while the remainder had both EMT and paramedic services in a layered response. I n later years, all areas had layered response. Thus, the majority of cases were treated with both EMT and paramedic services. The primary surveillance tool was the King County EMS incident form, completed by all 43 fire departments and all six paramedic programs in the study area. Identifying information was obtained for each case. In addition, information on cardiac rhythm was obtained. In most instances this was obtained by the paramedics, usually arriving at the scene within eight to ten minutes of the call. Other information routinely collected included whether the cardiac arrest was witnessed directly, the individual initiating CPR, the estimated time from collapse to initiation of CPR, and the estimated
8 2 / 1 1 0 3
0 - 17 Years
schernic heart e (61) 24%
Drowning (22) 9%
Other(43)" ]tory (24) 10%
Cardiac: Other (42) 17% 18 - 35 Years
Drowning and overdose (52) 1%
]tory (431) 6%
]rdiac: Other (266) 4%
Cardiac: Ischemic heart disease (5,706) 81% 36 + Years
A N N A L S OF EMERGENCY M E D I C I N E
21:9
SEPTEMBER 1992
CARDIAC ARREST Safranek, Eisenberg & Larsen
time from collapse to initiation of advanced cardiac life support. The time from collapse to initiation of CPR and advanced cardiac life support was estimated only for witnessed arrests on the basis of incident reports and telephone interviews with emergency personnel and bystanders. The etiolofor the cardiac arrest was determined from autopsy, hospital records, and incident reports. Younger patients were more likely to have had an autopsy. The autopsy rate was 81% for the 0- to 17-year-olds, 75% for the 18- to 35-year01ds, and 16% for the age 36-and-older group. Patients with cardiac arrest from motor vehicle accidents or other t r a u m a including traumatic suicides were excluded because we wished to focus on medical etiologies for cardiac arrest. Statistical differences were determined using the Z2 test. RESULTS
During the study period, 8,054 cardiac arrests met the case definition; 252 (3%) were among individuals 18 to 35 years of age, and 353 (4%) were among individuals 0 to 17 years of age. The other 7,449 (93%) cases were among individuals 36 and older. The most common etiology in the 18- to 35-year-old group was ischemic heart disease, accounting for 61 (24%) cardiac arrests. The second most common etiology was overdose, causing 60 (24%) cardiac arrests. Among the 0- to 17-yearolds, the most common etiology was sudden infant death syndrome, accounting for 182 (52%) cardiac arrests. The second most common etiology was drowning, causing 54 (15%) cardiac arrests. In the 36-and-over age group, the most common etiology was ischemic heart disease, accounting for 5,705 (81%) of all cardiac arrests. The second most common etiology was respiratory, causing 431 (6%) cardiac arrests. Etiologies for the cardiac arrests in the three groups are shown (Figure). ~The other cardiac category included congenital cardiac disorders, rheumatic heart disease, aortic valve disease, and cardiomyopathies. I n the 0- to 17-year-old age group, congenital heart disease was the most common other cardiac etiology. I n the 18-to-35 and 36-and-older age groups, valvular disease and cardiomyopathies were the most common. ECG rhythm interpretation was available in 92% of patients. The most common rhythm in the 18- to 35-year-old age group was asystole, accounting for 48% of all recorded rhythms. The second most common rhythm was ventricular fibrillation (31%). Among the 0- to 17-year-olds, the most Table 1. ECG rhythm associated with cardiac arrest: All etiologies
Rhythm Asystole Idioventricular Ventricular fibrillation/tachycardia Other
% 0-17 80 8 6 6
Age (yr) % 18-35 48 11 31 10
SEPTEMBER 1992 21:9 ANNALSOF EMERGENCYMEDICINE
% 36+ 33 9 46 11
common rhythm was asystole, accounting for 80% of all recorded rhythms. The second most common rhythm was idioventricular (8%). In the 36-and-over age group, the most common rhythm was ventricular fibrillation, accounting for 46% of all recorded rhythms. The second most common rhythm was asystole (33%). The rhythms recorded for the three age groups are listed (Table 1). The other category included nodal rhythms, various heart blocks, sinus bradycardia~ normal sinus, and sinus tachycardia. Survival by etiology is shown (Table 2). In the 0-to-17 group, there were no successful resuscitations in patients with apparent sudden infant death syndrome. In the 18-to-35 age range, 26% of patients with ischemic heart disease as the etiology of the arrest survived, while 18% survived in the 36and-over group (P = NS). Information on survival by first-recorded rhythm is shown (Table 3). The highest rates of survival in all age groups were seen when the first recorded rhythm was ventricular fibrillation or pulseless ventricular tachycardia. When the rhythm was asystole, all groups had a poor survival. Patients with witnessed arrests whose first recorded rhythm is ventricular fibrillation or ventricular tachycardia have better rates of resuscitation and long-term survival compared with patients without these characteristics.5 The 0-to-17 age group is excluded because there were insufficient cases in this category. The long-term survival for witnessed ventricular fibrillation in the 18-to-35 age group was 39%; in the 36-and-over age group, 34% survived (P = NS). For patients with witnessed arrest in rhythms other than ventricular fibrillation, the long-term survival in the 18- to 35-yearold age group was 20%; in the 36-and-over age group, 9% survived. DISCUSSION
The etiologies of cardiac arrest in young adults were somewhat different from those of children or older adults. There is less ischemic heart disease in this age group, and cardiomyopathies are proportionally more prevalent. In their report on prehospital sudden death in young adults, Raymond Table 2. Long-term survival by etiology
Etiology
0-17 No. %
Cardiac:lschemic heart disease Cardiac: Other Respiratory Overdose Drowning Sudden infant death syndrome Other
1 0 6 I 14 0 8
Total for all etiologies
30
14 0 21 20 26 0 13
8.5
Age (yr) 18-35 No. % 16 6 3 t0 6 O 10
26 14 13 17 27 0 23
45 17.9
36+ No. % 1,052 49 37 6 2
18 18 9 17 13
O O 18 3 1,164 16.5
1104/ 83
CARDIAC ARREST
Safranek, Eisenberg & Larsen
and colleagues reported a marked increase in coronary artery disease after the age of 35. They also found that cardiac disease not of coronary artery etiology was the predominate cause of sudden death u n d e r the age of 35.6 We found that the proportion of arrests caused by overdose is higher in the young adults than in either of the other groups. Mittleman and colleague reported the average age of cocaineassociated death to be 29 years. 7 Young adults were more likely to be in asystole and less likely to be in ventricular fibrillation or tachycardia than the older adults. The increase in asystole may be a result of the greater frequency of unwitnessed cases among young adults (49%) compared with older adults (37%). It may also be caused by the different mix of etiologies seen in this group. The young-adult group represents a transition in terms of age, etiology, and rhythm between the children and older adult groups. The 0- to 17-year-olds have a 7% incidence of cardiac arrests caused by heart disease, while the 18- to 35-year-olds and 36-years-and-older age groups had a 41% and 85% incidence, respectively. The ECG rhythms associated with cardiac arrests showed a similar progression. Ventricular fibrillation and tachycardia were seen in 6% of the arrests in children, while they accounted for 31% of arrests in Young adults and 46% of arrests in older adults. Although the incidences of particular rhythms were markedly different between age groups, the long-term survival based on these rhythms was similar. Survival from asystole was lbw in all age groups. The survival following ventricular fibrillation and tachycardia was nearly identical in all ages. Survival rates for children, young adults, and older adults were 25%, 28%, and 29%, respectively. These survival rates are comparable with the 23% overall survival reported by Clinton and colleagues in patients i to 40 years of age. For patients with a witnessed arrest of cardiac etiology where the first recorded rhythm was ventricular fibrillation or tachycardia, the survival rate was 39% for young adults and 34% for older adults. There appear to be no characteristic s unique to the youngadult group. Although there was no statistically significant increased survival in young adults following cardiac arrest, there was a trend toward increased survival in arrests of cardiac etiology and more specifically in witnessed arrests of cardiac etiology where the first recorded rhythm was ven-
tricular fibrillation or tachycardia. This increased survival may be a result of the overall better health of young adults and the likelihood that their heart disease is their only significant medical illness. This study had several limitations. Our surveillance system identified patients with cardiac arrest who received prehospital emergency medical care. The Surveillance system did not identify patients who died in the community without a resuscitation attempt. We specifically excluded traumatic deaths, wishing to focus on medical etiologies of cardiac arrest. Hence, the study does not define the epidemiology of death in young adults, but rather describes patients with nontraumatic cardiac arrests who receive CPR from emergency personnel. There was some imprecision in categorizing etiology of cardiac arrests because not all patients had an autopsy, although the younger patients were more likely than the older adults to have had an autopsy. There also was no mechanism to measure comorbidity such as underlying congestive heart failure, which would be a predictor of poor outcome. What are the implications of this survey for prehospital care of cardiac arrest? The young-adult group has a low incidence of cardiac arrest, less than children and older adults. Young adults are a very heterogeneous group in terms of the etiology of cardiac arrests. They show characteristics of both the younger and older populations. Although the incidence of arrests caused by ischemic heart disease is much less than in the older adults, there are a significant n u m b e r of cases of cardiac etiology with vcntricular fibrillation or tachycardia as the first recorded rhythm. The likelihood of resuscitation is very high for these rhythms, as it is in older adults. CONCLUSION
In terms of etiology and rhythm, young adults aged 18 to 35 appear to be a transitional group linking children and olderadult groups. There seem to be no characteristics unique to the young-adult population in terms of cardiac arrest. Survival following cardiac arrest was best predicted by first recorded rhythm and not the age of the victim.
Table 3.
Long-term survival by ECG rhythm Age (yr) Rhythm
0-17 No. %
18-35 No. %
36+ No. %
Asystole Idioventricular Ventricularfibrillation/tachycardia Other
10 4 3 11 5 25 , 11 55
5 4 3 11 21 28 13 52
42 2 36 6 927 29 145 18
8 4/ 1 1 0 5
ANNALS OF EMERGENCYMEDICINE 21:9 SEPTEMBER1992
~! CARDIAC ARREST
Safranek, Eisenberg & Larsen
REFERENCES I, Eisenberg MS, Bergner L, Hallstrom A: Epidemiology of cardiac arrest and resuscitation in a suburban community. JACEP1979;8:2-5. 2,Eisenberg MS, Bergner L, Hallstrom A: Epidemiology of cardiac arrest and resuscitation in children. Ann Emerg Med 1983;12:31-33. 3,ClintonJE, McGill J, Irwin G, et al: Cardiac arrest under age 40: Etiology and prognosis.Ann Emerg Med1984;13:1011-1014.
Address for reprints: Mickey Eisenberg, MD Center for Evaluation of Emergency Medical Services Emergency Medical Services Division 110 Prefontaine Place South, Suite 500 Seattle, Washington 98104
4,Ng AMY, Clinton JE, Peterson G: Nontraumatic prehospital cardiac arrest ages 1-39 years.Am J Emerg Meal 1990;8:87-91. 5,Eisenberg MS, Hallstrom A, Bergner L: The ACLS score. JAMA 1981;246:40-52. 6.RaymondJR, van den Berg EK, Knapp M J: Nontraumatic prehospital death in young adults.Arch Intern Med 1988;148:303-308. 7.Mittleman RE, Wetli CV: Death caused by recreational cocaine use. JAMA 1984;252:1889- 1893.
SEPTEMBER1992
21:9
ANNALS OF EMERGENCY MEDICINE
1106/85
