100 QUESTIONS IN CARDIOLOGY

(Michael S) #1

84 How do I investigate the relatives of a patient


with sudden cardiac death?


Niall G Mahon and W McKenna


In patients aged over 30 years by far the commonest cause of

sudden cardiac death is coronary disease (80%). In patients

younger than this, inherited disorders play a major role, with

hypertrophic cardiomyopathy accounting for approximately 50%

of these deaths. Although perhaps not entirely representative of the

general population, the most systematically collected data on

sudden death in young people comes from athletes. Common

causes of sudden death in young athletes are shown in table 84.1.

Aortic root dissection and arrhythmias due to accessory pathways

and long QT syndromes may also be causative. A specific diagnosis

in the deceased should be pursued by means of expert examination

of the postmortem heart if available and attempts to obtain ante-

mortem electrocardiograms and other investigations.

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Hypertrophic cardiomyopathy 51
Anomalous coronary artery 17
Other coronary disease 9
Myocarditis 5
Dilated cardiomyopathy 4
Ruptured aortic aneurysm 3
Aortic valve stenosis 3
Arrhythmogenic right ventricular cardiomyopathy 2
Mitral valve prolapse 2


From Basilico FC. Cardiovascular disease in athletes. Am J Sports Med1999; 2277 :
108–21.


In general first-degree relatives should undergo history,

physical examination, 12-lead electrocardiography and 2-D

echocardiography. Other investigations may also be performed

depending on the suspected cause of death, such as exercise

testing in suspected long QT syndrome. In the case of a suspected

inherited condition, if both parents of the deceased can be eval-

uated and found to be free of abnormalities, the condition causing
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