Scope and Nature of Sudden Cardiac Death before age 40 in Ontario: a report from the Cardiac Death Advisory Committee of the Office of the Chief Coroner



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Scope and Nature of Sudden Cardiac Death before age 40 in Ontario: A Report from the Cardiac Death Advisory Committee of the Office of the Chief Coroner
Caileigh M. Pilmer B.Sc., Bonita Porter MD, Joel A. Kirsh MD, Audrey L. Hicks Ph.D., Norman Gledhill Ph.D., Veronica Jamnik Ph.D., Brent E. Faught Ph.D., Doris Hildebrandt B.A., Neil McCartney Ph.D., Robert M Gow MBBS, Jack Goodman Ph.D., Andrew D. Krahn MD.

Author Affiliation:

Caileigh M. Pilmer, Andrew D. Krahn: University of Western Ontario, London, ON, Canada

Bonita Porter, Doris Hildebrandt: Office of the Chief Coroner, Toronto, ON, Canada

Joel A. Kirsh: The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada

Audrey L. Hicks: McMaster University, Hamilton, ON, Canada

Norman Gledhill, Veronica Jamnik: York University, Toronto, ON, Canada

Brent E. Faught, Neil McCartney: Brock University, St. Catharines, ON, Canada

Robert M Gow: Children's Hospital of Eastern Ontario, Ottawa, ON, Canada

Jack Goodman: University of Toronto, Mt. Sinai Hospital, Toronto, ON, Canada


Address for Correspondence:

Dr. Andrew Krahn

Arrhythmia Service

London Health Sciences Centre

339 Windermere Rd

London, Ontario CANADA

N6A 5A5

Tel: 1-519-663-3746



Fax: 1-519-663-3782

Email: akrahn@uwo.ca

Short Title: Sudden cardiac death before age 40 in Ontario
Word count: 3647
The authors have no conflict of interest to declare.
Abstract
Background: Understanding sudden cardiac death in the young may inform prevention strategies.

Objectives: To determine the scope and nature of sudden death in a geographically defined population.

Methods: We performed a retrospective population-based cohort study in Ontario, Canada of all sudden cardiac death cases involving persons aged 2-40 years identified from the 2008 comprehensive Coroner database. Of 1,741 coroner’s cases, 376 were considered potential sudden cardiac death cases and underwent review.

Results: There were 174 cases of adjudicated sudden cardiac death from a population of 6,602,680 persons aged 2-40 years. Structural heart disease was present in 126 cases (72%), 78% of which was unrecognized. There was no identifiable cause of death in 48 cases (28%), representing primary arrhythmia syndromes. The majority of decedents were male (76%) over the age of 18 (90%). The overall incidence of sudden cardiac death increased with age from 0.7/100,000 (2-18 years) to 2.4/100,000 (19-29 years) to 5.3/100,000 person-years (30-40 years). Persons experiencing sudden cardiac death under age 30 were more likely to have a primary arrhythmia syndrome (OR=2.97, p<0.001). The majority of events occurred in the home (72%); 33% of events in children/adolescents and 9% of events in adults occurred during reported moderate or vigorous exercise (p=0.002). There were no pediatric deaths during organized competitive sports.



Conclusion: The incidence of sudden cardiac death increases with age, typically occurring in a male at rest in the home with unrecognized underlying heart disease or a primary arrhythmia syndrome. Prevention strategies should consider targeting identification of unrecognized structural heart disease and primary arrhythmia syndromes.
Key words: sudden death, autopsy, heart disease, genetics

Introduction

Sudden cardiac death in the young is a tragic and devastating event for families and communities. It is currently not known how best to prevent or limit sudden cardiac death in the younger age group1-5. Characterization of the population that suffers sudden cardiac death would assist in understanding the scope and nature of the problem, and could potentially inform strategies targeting prevention 6,7,8,9. Ontario is Canada’s most populous province, with an ethnically, culturally, and socioeconomically diverse population of thirteen million inhabitants. In this province, coroners are mandated to investigate any and all deaths that are sudden, unexpected, or from non-natural causes. In 2008, of the 2864 deaths that occurred in the 2-40 age group, 1741 were investigated by the coroner’s office. These death investigations were obliged to answer the following five questions: who was the deceased, how, when and where the death occurred, and by what means the death occurred. Coroners in Ontario have the legal right to perform an autopsy to assist in their investigation of the death, and have access to additional services such as general and specialist pathologists and toxicology screening. Individual coroners also have the support of the Office of the Chief Coroner of Ontario (OCCO) for assistance and collaboration on complicated cases. The OCCO maintains a centralized, comprehensive database and death investigation files on all deaths investigated in Ontario. We sought to understand sudden cardiac death in persons aged 2-40 using this comprehensive provincial registry to enable accurate determination of incidence and cause of sudden cardiac death.


Methods

Data Collection

This epidemiologic study incorporated a retrospective cohort design. Cases of potential relevance were identified from the comprehensive database of the Office of the Chief Coroner of Ontario (OCCO), which contains data on all cases reported to and investigated by coroners in Ontario. All files contained a coroner’s report (the Coroner’s Investigation Statement Form 3), and an autopsy report (Report of Post Mortem Examination) if an autopsy was conducted. Other information, such as police reports and reports from other investigating bodies including the Children’s Aid Society and Workplace Safety and Insurance Board, was available depending on circumstances of death. In the case of inquest, a full inquest file including all hearings and final recommendations was available. The coroner’s report included personal information and findings of the death investigation – date of death, environment and manner of death, involvements, reported medical cause of death, as well as a narrative section that included other relevant information such as past medical history that was obtained from medical records and interviews of family members, friends and eyewitnesses. Further detail regarding the structure and definitions used in the Ontario Coroner system is presented in the online Appendix (Tables 1 and 2), in conjunction with a sample Coroner Investigation report.

Sudden death was defined as an event resulting in death or terminal life support within one hour of collapse, or an unwitnessed, but unexpected death in the absence of known or suspected condition that may predispose to terminal illness 10. Deaths were further defined as cardiac in origin if there was autopsy-confirmed heart disease with clinical circumstances consistent with a potential cardiac etiology of death. Sudden unexplained death (SUD) was defined as any sudden death unexplained by pre-existing disease and without identifiable cause on post-mortem examination. Sudden unexpected death below the age of two years was considered a separate entity and was not included.

Using the OCC database, all files that satisfied the following three inclusion criteria were reviewed: 1) date of death in 2008 (the most recent calendar year for which comprehensive electronically-searchable data were available), 2) age at death for selection of patients aged 2-40 inclusive, and 3) manner of death listed as “natural–cardiac”, “natural–other”, “accidental”, or “undetermined”. This yielded 978 potential cases (Figure 1). These cases were reviewed for relevance, and cases that were not sudden, not unexpected, or not of possible cardiac etiology were excluded. This was accomplished in two steps – the first by examining headings such as cause of death and excluding those that were clearly non-cardiac, which excluded 354 files. The second step involved reviewing the remaining 624 files in their entirety, which excluded a further 248 files. Because of the breadth of the inclusion criteria in terms of manner of death, many deaths were readily excluded based solely on cause of death (including deaths classified as undetermined in which the cause of death was gunshot wound, and natural deaths in which the cause of death was clearly non-cardiac such as pneumonia or sepsis). Accidental deaths in which the cause of death was attributed to acute drug toxicity were excluded, but those in which alcohol and/or drugs were contributing factors were reviewed individually for relevance. Similarly, passengers in motor vehicle accidents were excluded without review of the chart, but the drivers were reviewed individually.

Data were collected on the remaining 376 cases, which were considered possible sudden cardiac deaths. These data included demographic information such as date of birth, sex, death information including date, location, cause, and manner of death. Autopsy findings, especially related to cardiac conditions, were noted as was any known history of cardiac or other disease. Cardiac pathology discovered on autopsy was listed separately from any known pre-existing cardiac conditions, as documented in the coroner’s report. Since the death files did not contain copies of the individual’s medical charts, previous medical conditions were noted at the discretion of the investigating coroner and abstracted by a single investigator (CP).

Additional data that were collected included premonitory symptoms, nature of physical activity and/or intensity at time of death, medication or substance use, cardiac risk factors, and narrative details about the circumstances of death from the available evidence. Premonitory symptoms included potential cardiac symptoms such as chest pain, shortness of breath, palpitations and syncope. Further investigations such as requests for additional medical records or personal interviews were not obtained because of the retrospective nature of the study. Physical activity level at time of death was determined from the coroner’s narrative, and was classified as during sleep, at rest, during light to moderate activities of daily living (ADLs), during moderate to vigorous exercise (estimated workload ≥3 metabolic equivalents), or unknown. Decedents were classified as dying at rest if the event was described as such by an eyewitness, or if the decedent was found in a position suggesting rest, such as supine or seated. Light to moderate ADLs included activities such as housework, and other non-physically strenuous activities such as driving. Moderate to vigorous exercise included any sporting or fitness activities such as swimming, running, and team sports, as well as any strenuous physical work or chores such as shoveling snow.


Case definition

Cases were defined by incorporating information from across the file, including death factor, medical cause of death, underlying pathology, description of the environment and circumstances, and contributing factors and co-morbidities. The review adopted an inclusive approach to ensure that unrecognized circumstances such as drowning or single vehicle accidents would be reviewed to detect possible syncope or sudden death while swimming or driving. Cases were included following adjudication by three of the authors - the primary author, an experienced expert in cardiac arrhythmia and sudden cardiac death (AK) and an experienced expert in cardiac pathology and the provincial death investigation system (BP, Deputy Chief Coroner, Province of Ontario). In total, this review excluded a further 202 cases leaving 174 of the possible 376 cases. Cases were included when sudden cardiac death occurred without the identification of any additional factors that could have contributed to death, including toxicology, alcohol or hazardous conditions. Also included were cases when sudden cardiac death occurred with a single potentially contributory factor (other than cardiac disease or primary arrhythmia), but which was not of sufficient gravity that it was expected to cause sudden cardiac death. For example, a patient with unrecognized hypertrophic cardiomyopathy (HCM) who was involved in a fatal single vehicle accident with significant trauma that was unlikely to be fatal, where there was no evidence of attempt to avoid collision, was presumed to represent a fatal arrhythmia resulting in loss of consciousness while driving.

The adjudicated cases were further sub-classified into either sudden cardiac death with no anatomical cause, or sudden cardiac death with underlying structural heart disease. Structural heart disease was deemed either ischemic or non-ischemic, and recognized or unrecognized prior to death based on the narrative in the coroner’s investigation report.

Statistic Analysis

The authors had full access to the data at the OCCO and take full responsibility for its integrity. Statistical analysis was conducted using Graphpad Prism version 5.0d (La Jolla, CA) by one of the authors (CP). Descriptive statistics between those with SCD and SUD, as well as across age groups were compared using one-way ANOVA for continuous variables (means and standard deviations) as appropriate. The chi-square test was used for categorical variables (proportional rates and confidence intervals). Non-parametric multiple comparison analysis was used to determine simultaneous proportional group differences. Overall and age related incidence rates were calculated using the reported sudden cardiac death cases relative to appropriate at risk population size for Ontario in 2008 with 95% confidence intervals derived from the Poisson distribution. Level of statistical significance was set at p<0.05.


Results

In 2008, there were 174 cases adjudicated to have sudden cardiac death from an estimated population of 6,602,680 persons aged 2-40 11. Based on this information, the incidence of sudden cardiac death in the overall population was 2.6/100,000 person-years. The incidence of sudden cardiac death increased with age, from 0.7/100,000 person-years in those aged 2-18 to 2.4/100,000 person-years in those aged 19-29 to 5.3/100,000 person-years in those aged 30-40. The majority of decedents were male (76%), and over the age of 18 (90%, Table 1).


Attributed Cause of Death

Of the 174 cases of sudden cardiac death, 126 cases had underlying structural heart disease (72%, 95% CI=60-85), while 48 (28%, 95% CI=20-35) had no identifiable anatomic or toxicological cause of death; sudden unexplained death likely representing primary arrhythmia syndromes. Of the 126 cases with structural heart disease, 104 cases were acquired (ischemic or non-ischemic cardiomyopathy etc., 83%), 20 were congenital or developmental (inherited cardiomyopathy, congenital anomalies, 16%) and two were both. Persons under age 30 were more likely than those aged 30-40 to have a primary arrhythmia syndrome (42% versus 19%; OR=2.97, 95% CI= 1.60-6.28; p<0.001, Figure 2). There was no difference in frequency of a primary arrhythmia syndrome between those less than 18 years and those 19 years to 29 years (44% vs. 37%, p= 0.59). Most structural heart disease was unrecognized (78% of structural heart disease, Table 2). The most common structural heart disease pathology was coronary artery disease, which was found in 36% of all sudden cardiac deaths, and in 49% of those with structural heart disease (Table 1). The non-ischemic causes of structural heart disease are listed in Figure 3, with the most common cause being dilated cardiomyopathy (DCM). Of note, all the included aortic dissections were non-traumatic. Details regarding age specific causes of death are summarized in Table 3.

Overall, 16% of cases had previously recognized heart disease (95% CI, 11-22%). There was no difference in proportion of recognition of underlying heart disease between ischemic and non-ischemic disease (16% vs. 28%, p=0.13), and no difference in proportion of recognition of underlying heart disease between adults and children (22% recognized vs. 30% recognized, p=0.69). Overall, unrecognized underlying heart disease and primary arrhythmia syndromes accounted for 84% of deaths (n=146).

After exclusion of 7 cases with both atherosclerosis and other forms of heart disease, there was no sex difference in patients with atherosclerotic coronary artery disease, non-ischemic cardiovascular disease and primary arrhythmia syndromes (21%, 27% and 26% female, p=0.77). However, the average age of patients with atherosclerotic coronary artery disease was significantly older than patients with non-ischemic or no underlying heart disease (36±5 vs. 29±9 vs. 28±10 years, p<0.0001, Figure 4, supplemental Table 3).



Location and Physical Activity

The majority of events occurred in the home (72%), with only a small number occurring in public places such as work, school, or athletic facilities. The absence of underlying heart disease did not impact location of death (75% vs. 65% at home, p=0.19).

Overall, 11% of events (20/174) occurred during moderate to vigorous exercise. Whereas the vast majority of events occurred at low activity levels (sleep, rest, ADLs) in the older age group (14 of 156), one third of events occurred during moderate activity in the 2-18 years age group (6 of 18); the difference between age groups was significant (9% vs. 33%, p=0.002). There was no difference between the proportion of cases occurring during exercise with or without underlying structural heart disease (10% vs. 15%; p=0.39). Only 7 of the 48 cases with no identified anatomical cause of sudden cardiac death, and 13 of 126 cases with underlying heart disease, occurred during exercise (15% vs. 10%; p=0.55). Exercise related events occurred while swimming, scuba diving, in physical altercations, or doing strenuous manual labor.
Premonitory Symptoms

Cases with underlying heart disease, whether it was recognized or unrecognized, were more likely than cases without structural disease to display premonitory symptoms (54% vs. 25%; p<0.0001). There was no difference in likelihood of prodrome between cases of ischemic and non-ischemic sudden cardiac death (56% vs. 54%; p=0.88). Women were more likely than men to have premonitory symptoms (61% vs. 41%; p=0.007). A separate summary of the characteristics of the pediatric population is presented in Appendix 1.


Discussion

In the current study, we have identified an increased risk of sudden cardiac death with age, which primarily affects males at rest with unrecognized heart disease. Before the age of 30, deaths are predominantly related to unrecognized cardiomyopathic processes and primary arrhythmia syndromes leading to sudden unexpected death, which increase in incidence in adolescence and early adulthood. Death occurs predominantly at rest and in the home. The strength of the current study is the comprehensive and systematic nature of the data collection process in a defined population without ascertainment bias.

The largest comparable dataset is derived from the Veneto region in Italy, where routine pre participation screening is performed to detect underlying heart disease12-16. They evaluated 300 cases of sudden cardiac death among young adults (ages 12 to 35 years) from a population of 4.4 million. Participants had undergone screening between 1979 and 1999, and a similar proportion of SUD was reported (26% vs. 28% in the current study), but with less atherosclerosis (21% vs. 36%). The Italian study population was younger (upper age limit of 35 vs. 40), more ethnically homogenous, and self-selected by their interest in sports, which may all have contributed to a reduced proportion of participants at risk for atherosclerosis. The current study involves a more recent sample that is population based, derived from a larger and more ethnically diverse population in Ontario. Unlike the Veneto study, arrhythmogenic right ventricular dysplasia was less commonly seen in our larger and ethnically diverse population (5% v 13%).

The incidence and nature of sudden cardiac death in a large but select group of US military recruits has been reported on multiple occasions 3,10,17. Among 6.3 million initial entry trainees from 1977 through 2001 with a median age of 19 years, there were 126 sudden, non-traumatic deaths during training, with no previously documented cardiovascular disease and no known family history. Not surprisingly, the leading causes of death were sudden unexplained cardiac death (34.9%), or death related to coronary pathology, one third of which was anomalous coronary arteries (30.9%) 3. In a recent study of 902 predominantly male older subjects (age 38±11 years) from the same group who underwent standard, military health surveillance, SUD was responsible for 21% of cardiac related deaths 10. Studies from the United States have reported a higher prevalence of HCM in sudden cardiac death, particularly when focusing on athletes 18-20. In the current study with a more diverse population, HCM accounted for only 7% of all cases in this age group, and 21% of non-ischemic cardiovascular causes. In contrast, dilated cardiomyopathy was the dominant non-atherosclerotic cause in the current study. This diagnosis was typically assigned to patients with idiopathic dilated cardiomyopathy, as well as myocarditis with left ventricular dysfunction. These were not coded separately.

Several additional smaller population studies have reported comparable results. In a study of 54 sudden cardiac deaths age 20-40 in Olmstead County, Minnesota, atherosclerosis (35%) was the most common cause of death, with SUD in only 13% 21. In an analysis of a population of approximately two million Australian subjects, SUD occurred in 31% of subjects 4. A nationalized autopsy database in Sweden reported SUD in 21% and HCM in 11% of 15-35 year olds 2, compared to 27% and 15% respectively in Ireland 5. A review of 35 SUD coroner’s cases in British Columbia with a population of 4 million suggested that SUD cases do not typically precipitate a systematic assessment of family members 8.

Based upon our findings, the context of sudden cardiac death is at odds with popular media depiction in high profile publicized deaths in athletes during vigorous exercise 18,19,22-24. In those 19 years of age and older, only 9% of the cases of sudden cardiac death occurred during physical activity. This is comparable to the Danish sudden death registry, where only 11% of deaths before age 35 occurred during sports or vigorous activity 25. However, given that the time spent exercising represents a very small proportion of the total day, this 9% supports previous observations that exertion represents a state of higher risk in adults 26,27. Despite this, a population perspective reflecting previous studies in older adults strongly supports the overall protective effect of regular exercise, and suggest that interventions such as automatic external defibrillators (AEDs) will have a modest effect if targeting younger athletes during participation 28. While this does not negate the efficiency of placing AEDs in public areas, it does suggest that it will have a modest impact in this population. By comparison, 33% of deaths in those 2-18 years occurred during moderate activity, which has a lower risk than intensive exercise24. As well, although 27% of pediatric deaths were classified as occurring during low intensity activities (not sleep), retrospectively determining the intensity of play that may have been associated with adrenergic stimulation (such as video games) is difficult.

The presence of premonitory symptoms as a sentinel sign preceding sudden cardiac death raises the prospect that targeting these may unmask those at risk and identify those who are eligible for prevention strategies. This is certainly an appealing interpretation, although it is hampered by the low specificity of symptoms such as presyncope or palpitations, and the obvious recall bias of the remaining friends and family who were interviewed during the death investigation. Limited data suggest that clear sentinel symptoms such as worrisome syncope are present in as few as 13-30% of cardiac arrest survivors with latent causes of arrest such as primary arrhythmia syndromes and familial cardiomyopathies 29. The current study was clearly limited by the scope of historical detail contained in the coroner’s narrative, but does suggest that a potential symptom was present in half of the patients, and significantly more so in females.

The frequency of unrecognized heart disease is strong rationale for early screening. Early onset coronary artery disease may present as sudden cardiac death because of plaque rupture without ischemic preconditioning, leading to ventricular fibrillation 30. The frequent absence of sufficient warning symptoms suggests that age 30 may be a reasonable time to consider screening for coronary artery disease. Nonetheless, a prevention strategy and public education of warning symptoms are clearly established mandates that have reduced the burden of both atherosclerotic heart disease, and recognition of other mechanisms. Of interest, congenital heart disease was rare in the current series, in part because death in the context of manifest and severe congenital heart disease was not likely to be reported as sudden or unexpected.

The limitations of the study are clear and not without importance. The data were extracted from Coroner’s reports that are generated with the primary intent of establishing the cause of death, and not focusing on the various relevant aspects of the medical history. Additional medical detail from other sources including previous medical records and structured interviews of friends and family may have provided further insight into premonitory symptoms and the nature and intensity of physical activity. The retrospective nature of the study precluded extensive data collection including interview of family members, review of source documents in the medical record or detection of contributing factors such as fever or electrolyte disorders. Thus adjudicating the cause of death is challenging at the best of times, potentially more so when data is limited. Despite this, coroners in Ontario are obliged to obtain all relevant data that may have contributed to death and relevant data on location of death and level of activity were captured in the vast majority of cases. Prescription and over the counter medications may not have been completely captured, although toxicology is performed in all cases where there is suspicion of a contribution to cause of death. Lastly, despite the systematic and comprehensive nature of the Ontario Coroner system, we cannot exclude the possibility that a small number of deaths were not reported to the local or regional Coroner, or were not captured in this analysis due to clerical error.
Conclusion

Sudden cardiac death in young persons increases with age, and is more common in males. In adults, death typically occurs in the home at rest, in a person with unrecognized underlying heart disease or a primary arrhythmia syndrome. In children and adolescents, death is more likely to be associated with physical activity, though not typically during competitive sports. Prevention strategies should consider targeting identification of unrecognized structural heart disease and primary arrhythmia syndromes, which together accounted for 84% of deaths. Other best practices that may reduce the incidence of sudden cardiac death include public education, targeting pre-participation screening to middle age and older athletes and the placement of AEDs in public places.


Acknowledgement
The authors have no conflict of interest to declare.
All authors had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis
Funding Sources: Dr. Krahn is a Career Investigator of the Heart and Stroke Foundation of Ontario (CI6498). The study was supported by the Office of the Chief Coroner of Ontario and the Heart and Stroke Foundation of Ontario (T6730).
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Table 1. Summary of 2008 reported sudden cardiac deaths by the Ontario Coroner’s Office





Total Sudden cardiac deaths

Structural Heart Disease Deaths




N=174

N=126




N

% (CI)

% (CI)













No anatomical cause

48

28(22-35)




Structural heart disease

126

72(65-79)




Ischemic

62

36(29-43)

49(41-58)

Non ischemic

57

33(26-40)

45(37-54)

Both

7

4(2-8)

6(3-11)

Recognized Heart Disease

28

16(11-22)

22(16-30)

Age










Age 2-11

9

5(3-10)




Age 12-18

9

5(3-10)




Age 19-29

Age 30-40



47

109


27(21-34)

63(55-69)





Sex (male)


133

76





Prodrome










Reported prodrome (specific)

51

29(23-36)




Reported prodrome (non specific)

29

17(12-23)




No reported prodrome

94

54(47-61)



* There was no difference in likelihood of prodrome between cases of ischemic and non-ischemic SCD (56% vs. 54%, p=0.88). Women were more likely than men to have prodromic symptoms (61% vs. 41%, p=0.007). CI = 95% confidence interval.




Table 2. Summary of sudden cardiac deaths by age and sex.





All

Age

Sex







≤18

%(CI)

>18

%(CI)

Male

%(CI)

Female

%(CI)

Sudden cardiac death

174

18

10(6-15)

156

90(76-100)

133

76(63-89)

41

24(16-31)

No anatomical cause

48

8

17(5-28)

40

83(6-100)

35

73(49-97)

13

27(12-42)

Structural heart disease

126

10

8(3-13)

116

92(75-100)

98

78(62-93)

28

22(14-31)

Ischemic

62

0

0 (0)

62

100(75-100)

49

79(57-100)

13

21(10-32)

Non ischemic

57

10

18(7-28)

47

82(59-100)

42

74(51-96)

15

26(13-40)

Both

7

0

0 (0)

7

100(26-100)

7

100(26-100)

0

0(0)

Recognized

28

3

11(0-23)

25

89(54-100)

23

82(49-100)

5

18(2-34)

Unrecognized

98

7

7(2-12)

89

93(74-100)

75

77(59-94)

23

23(14-31)



Table 3. Detailed causes of death by age group


 

 




 Age

 

 

All

2 to 18

19 to 30

31-40

Sudden cardiac death

174

18

51

105

No anatomical cause

48

8

21

19

Structural heart disease

126

10

30

86

Ischemic

62

0

13

49

Non ischemic

57

10

17

30

HCM

12

2

4

6

DCM

25

1

7

17

Myocarditis

9

2

3

4

Aortic dissection

9

0

3

6

Cardiac tamponade

5

0

1

4

Endocarditis

2

0

1

1

ARVC

3

3

0

0

Both

7

0

0

7



Figure 1. Death review and classification of all potential sudden cardiac deaths in Ontario

Figure 2. Cause of sudden cardiac death by age

Figure 3. Non-ischemic cardiovascular causes of sudden cardiac death

Note: DCM = Dilated cardiomyopathy; HCM=Hypertrophic cardiomyopathy; ARVC = Arrhythmogenic right ventricular cardiomyopathy; HD = Heart disease




Figure 4. Difference in age between groups based on the nature of underlying heart disease. Bars represent medians, boxes represent interquartile range, and range in the wide bars.
encypted data:active work things:ontario coroner sudden death porter cdac:cdac pilmer abstract and manuscript:final figures:figure 4.jpg

Online Appendix
Supplemental Table 1. Description of the Coroner System in Ontario


Organization

Chief Coroner

Regional Supervising Coroners (n=11)

Local coroners (n=320)


Roles of the Office of the Chief Coroner

Conduct death investigations and inquests

Make recommendations to improve public safety



Death Investigations

Seek to answer five questions about the death:

  1. Who was deceased?

  2. How the death occurred

  3. When the death occurred

  4. Where the death occurred

  5. By what means the death occurred

Supplemental Table 2. Coroner’s file definitions


Manner of Death

All coroner’s cases must determine by what means the death occurred. Each death is classified into one of six categories: natural, accidental, homicide, suicide, skeletal/archeological remains, or undetermined. The category of natural manner of death is further subdivided.

Cause of Death

The proximal, medically determined reason for the death, in the coroner’s own words.

It is possible to have a death where the manner is undetermined but the cause of death is known.





Supplemental Table 3. Summary of cardiac deaths by age and sex






All







Age













Sex













2-18yrs

%(95%CI)

19-29yrs

%(95%CI)

30-40yrs

%(95%CI)

Male

%(95%CI)

Female

%(CI)

Sudden cardiac death

174

18

10(7-16)

47

27(21-34)

109

63(55-69)

133

76(70-82)

41

24(18-29)

No anatomical cause

48

8

17(8-30)

19

40(27-54)

21

43(31-58)

35

73(59-84)

13

27(17-41)

Structural heart disease

126

10

8(4-14)

28

22(16-30)

88

70(61-77)

98

78(70-84)

28

22(16-30)

Ischemic

62

0

0

11

18(10-29)

51

82(71-90)

49

79(67-87)

13

21(13-33)

Non ischemic

57

10

18(10-30)

17

30(20-43)

30

53(40-65)

42

74(61-83)

15

26(17-39)

Both

7

0

0

0

0

7

100(60-100)

7

100(60-100)

0

0(0)

Recognized

28

3

11(3-28)

6

21(10-40)

19

68(49-82)

23

82(64-93)

5

18(7-36)

Unrecognized

98

7

7(3-14)

22

22(15-32)

69

70(61-79)

75

77(67-84)

23

23(16-33)


Supplemental Summary: Pediatric Population
There were 18 adjudicated cases of SCD giving an incidence of 0.7/100,000 persons aged 2 to 18 years (95% CI 0.4 to 1.1/100,000). No anatomical cause was found in 8 (44%, 95% CI 25% to 66%). No cases of ischemic heart disease were identified. Structural heart disease was not previously identified in the majority (70% of those with heart disease, 95% CI 39% to 90%). Overall, there was no pre-existing cardiac diagnosis in 83% (15/18, 95% CI 60% to 95%).

Most deaths occurred during sleep or light activities (11/18; 61% 95% CI 39% to 80%) with only 6 occurring during moderate activity (33% 95% CI 16% to 56%). Activity level could not be ascertained in one case. There was no difference in level of activity at time of death between those with and without heart disease (p= 0.34, Fisher’s exact test). Death during organized, competitive sporting activity was not represented in this cohort of cases. Location of event was identified from records in 10 cases, with the majority of these being at home (6 cases) and at school (2 cases).


Supplemental Figure 1. Sample redacted Coroner’s Investigation Statement
encypted data:active work things:ontario coroner sudden death porter cdac:cdac pilmer abstract and manuscript:final figures:online appendix.pdf


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