Elsevier

Heart Rhythm

Volume 7, Issue 10, October 2010, Pages 1383-1389
Heart Rhythm

Focus issue: Sudden cardiac arrest
Clinical
Diagnostic yield in sudden unexplained death and aborted cardiac arrest in the young: The experience of a tertiary referral center in The Netherlands

https://doi.org/10.1016/j.hrthm.2010.05.036Get rights and content

Background

In sudden unexplained death (SUD) in the young (age 1–50 years), cardiologic and genetic examination in surviving relatives may unmask the cause of death in a significant proportion. The causes of aborted cardiac arrest (ACA) in this age group likely are similar to those in sudden cardiac death. However, there is a paucity of recent data on this topic.

Objective

The purpose of this study was to gain insight into the yield of current diagnostic strategies used in relatives of SUD victims and in ACA victims aged 1–50 years in our dedicated tertiary referral center.

Methods

We studied (1) all consecutive families who presented to the cardiology department for examination because of ≥1 first-degree related SUD victim aged 1–50 years and (2) all consecutive ACA victims aged 1–50 years who presented to the cardiology department from 1996 to 2009. Comprehensive cardiologic and genetic examination was performed in both populations.

Results

A certain or probable diagnosis was made in 47 (33%) of 140 SUD families, including 45 (96%) cases of inherited cardiac diseases. Long QT syndrome (19%) was the most prevalent diagnosis. In 42 (61%) of 69 ACA victims, the cause of the event was determined (inherited in 31 [74%]). Hypertrophic cardiomyopathy was most prevalent (17%).

Conclusion

The yield of the current diagnostic workup in relatives of young SUD victims is 33% and is almost twice as high in young ACA victims. Inherited cardiac diseases are predominantly causative in both groups.

Introduction

When autopsy is performed after the sudden death of an individual aged 1–50 years, structural cardiac disease is diagnosed in ∼69%,1 termed sudden cardiac death (SCD). Most causes of SCD are (potentially) inherited. The cause of the fatal event remains unexplained after autopsy in ∼18% (range 6%–35%) of patients.1, 2, 3, 4, 5, 6, 7 In these cases of sudden unexplained death (SUD), molecular autopsy of the deceased and cardiologic and genetic examination of relatives may unmask the cause of death in a significant proportion.8, 9, 10, 11 Identification of inherited cardiac diseases provides the opportunity to identify surviving relatives at risk for SCD and to take preventive measures.

The causes of aborted cardiac arrest (ACA) in victims aged 1–50 years likely are similar to those in SCD, and the eventual outcome of cardiac arrest (death in SCD and alive in ACA) is mostly determined by circumstances at the time of cardiac arrest.12, 13 Thus, identification of the underlying cause of ACA in the young has comparable significance for relatives as SCD/SUD in the young. However, no studies on the causes of ACA in the young have been published, apart from 10 pediatric ACA victims from our center.10 ACA at any age is estimated to be idiopathic in only ∼5%.14

In this study, we sought to determine and compare the yield of comprehensive cardiologic and genetic examination in surviving relatives of SUD victims aged 1–50 years and in victims of ACA of the same age to gain insight into the state of the art of the current diagnostic strategies used in both populations in our dedicated tertiary referral center.

Section snippets

Sudden unexplained death

SUD was defined as out-of-hospital natural death in a previously healthy individual whose family had no known inherited cardiac disease in whom death occurred within 1 hour after the start of complaints or within 24 hours of the victim being seen alive and well, and in whom autopsy was not performed or initially did not explain the death.

Aborted cardiac arrest

ACA was defined as an out-of-hospital unexpected, abrupt loss of consciousness with loss of vital signs (pulse, blood pressure, respiration) within 1 hour of

SUD families

The study included the surviving relatives of 140 SUD victims aged 1–50 years (Table 1). Ninety-nine (71%) were male, and 21 (15%) experienced at least one previous unexplained syncope. Two (1%) had a previous unexplained ACA in the 1980s and did not receive an implantable cardioverter-defibrillator. Autopsy was performed in 64 (46%) cases.

In six families, only one second-degree relative of the SUD victim presented to the cardiogenetics department. In the remaining 134 families, 340 (53%) of

Main findings

In this series of cardiologic and genetic assessment of both surviving relatives of SUD victims and victims of ACA aged 1–50 years, a diagnosis was made in 33% and 61%, respectively. Inherited cardiac diseases accounted for 96% of the diagnoses in the SUD families and 74% of the diagnoses in the ACA victims.

Comparison of yield in SUD families and ACA victims

The diagnostic yield within the two populations described in the present study cannot be well compared because the SUD victims formed a selected population (noncardiac and structural cardiac

Conclusion

Comprehensive cardiologic and genetic examination of relatives of young SUD victims results in a certain or probable diagnosis in one third of cases. In young ACA victims, the yield of the current diagnostic workup is 61%. In both groups, the majority of detected diagnoses is inherited.

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    Drs. van der Werf, van Langen, and Wilde were supported by a grant from ZorgOnderzoek Nederland Medische Wetenschappen (ZonMW, Grant 120610013). Dr. Wilde was supported by a grant from Fondation Leducq Trans-Atlantic Network of Excellence, Preventing Sudden Death (Grant 05-CVD-01). Dr. Tan was supported by the Netherlands Organization for Scientific Research (NWO, Grant ZonMW-VICI 918.86.616).

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