Conditions present at birth
- Inherited (passed on from parents/relatives) conditions of the heart muscle:
- Hypertrophic Cardiomyopathy – hypertrophy (thickening) of the left ventricle; the most common cause of sudden cardiac arrest in athletes in the U.S.
- Arrhythmogenic Right Ventricular Cardiomyopathy – replacement of part of the right ventricle by fat and scar; the most common cause of sudden cardiac arrest in Italy.
- Marfan Syndrome – a disorder of the structure of blood vessels that makes them prone to rupture; often associated with very long arms and unusually flexible joints.
- Inherited conditions of the electrical system:
- Lonq QT Syndrome – abnormality in the ion channels (electrical system) of the heart.
- Catecholaminergic Polymorphic Ventricular Tachycardia and Brugada Syndrome – other types of electrical abnormalities that are rare but run in families.
- NonInherited (not passed on from the family, but still present at birth) conditions:
- Coronary Artery Abnormalities – abnormality of the blood vessels that supply blood to the heart muscle. The second most common cause of sudden cardiac arrest in athletes in the U.S.
- Aortic valve abnormalities – failure of the aortic valve (the valve between the heart and the aorta) to develop properly; usually causes a loud heart murmur.
- Non‐compaction Cardiomyopathy – a condition where the heart muscle does not develop normally.
- Wolff‐Parkinson‐White Syndrome –an extra conducting fiber is present in the heart’s electrical system and can increase the risk of arrhythmias.
Conditions not present at birth but acquired later in life:
- Commotio Cordis – concussion of the heart that can occur from being hit in the chest by a ball, puck, or fist.
- Myocarditis – infection/inflammation of the heart, usually caused by a virus.
- Recreational/Performance‐Enhancing drug use.
Idiopathic: Sometimes the underlying cause of the Sudden Cardiac Arrest is unknown, even after autopsy.