What Do We Mean by Sudden Death?

• Sudden death is an unexpected death in an otherwise healthy person, occurring within a short time frame (24 hours) from the onset of symptoms.

• Sudden death due to inherited heart conditions is labeled as sudden cardiac death, and in this case, it requires screening the family to rule out these conditions and prevent other incidents.

• Some cases of sudden death may occur with a background of chronic illnesses that directly cause the death (such as blood clots, strokes, heart attacks, or cancer). In these instances, the death is not classified as a sudden cardiac death due to inherited heart conditions that requires family screening, as it is usually a result of the chronic illness itself.

What Is the Difference Between Sudden Cardiac Death, Cardiac Arrest, and Heart Attack?

• Cardiac Arrest: A sudden stop in the pump function of the heart, leading to reduced blood flow to body organs. It can be caused by various conditions affecting the heart or other organs, and if not promptly resuscitated, cardiac arrest leads to sudden cardiac death.

• Heart Attack: A severe and abrupt blockage in the coronary arteries, leading to reduced blood flow to the heart muscle and causing intense chest pain. Heart attacks are among the most common causes of cardiac arrest (though not all cardiac arrests are due to heart attacks).

• Sudden Cardiac Death: An unexpected death occurring within a short time frame (24 hours) from the onset of symptoms.

What Is the Relationship Between Sudden Cardiac Death and the Need for Family Screening?

If a sudden cardiac death occurs in a family, screening of other family members is necessary to rule out inherited heart conditions that may put other members at risk of sudden cardiac death.

Who Needs Family Screening When Sudden Cardiac Death Occurs?

Family screening is required for first-degree relatives of the person who suffered a sudden cardiac death if there is suspicion of an inherited condition by the treating physician (such as death at a young age). These individuals include the deceased's parents, siblings, and/or children.

What Does Family Screening Involve?

Initial family screening includes an echocardiogram (ultrasonic images of the heart), ECG, exercise stress test, and lipid profile test. Based on preliminary findings, additional testing such as cardiac MRI or genetic testing may be required.

Is It Possible to Undergo Screening and Receive Normal Results?

The likelihood of discovering an inherited heart disease in the families of sudden cardiac death victims ranges between 20-50%. When the results come back normal, this could be due to several reasons:

• The deceased may have had a non-heritable heart disease that was not diagnosed (not hereditary and doesn’t affect family members), with common causes including blocked arteries or heart failure.
• The presence of a novel genetic variation/mutation that occurred for the first time in the deceased (not inherited from the family).
• Non-cardiac factors that put the deceased at risk of a cardiac arrest that are not inherited, such as a blood clot in the pulmonary artery (due to immobility, post-surgery, or after childbirth), infections or illness at the time of the event, choking incidents, or brain hemorrhage.

When family members of sudden cardiac death victims are screened and the results are normal, it is generally an indicator that there is no inherited heart conditions. Studies have shown that individuals who are screened and receive normal results live normal lives without an increased risk of sudden death from inherited heart conditions.

Examples of Sudden Cardiac Death

• Death while sleeping.
• Death during physical exertion or sports activity (especially drowning while swimming).
• Death during routine activities, such as talking, praying, or doing household work.
• Death at a young age without a clear medical explanation.

Does Sudden Cardiac Death Have Preceding Symptoms?

Sudden cardiac death may be preceded by symptoms such as chest pain, shortness of breath, palpitations, or fainting. These symptoms often correlate with an undiagnosed heart condition. However, sudden cardiac death often occurs without prior symptoms, highlighting the importance of family screening even if no symptoms are present.

Causes of Sudden Death

Inherited Arrhythmias:

• Brugada Syndrome: A defect in cardiac cell channels causing electrical disturbances that lead to cardiac arrest.
• Long QT Syndrome: Prolonged electrical activity in the heart's electrical waves, increasing the risk of sudden death, and can be triggered by specific events such as certain medications, exercise, pregnancy, or auditory triggers.
• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): Irregular heart rhythms often causing fainting, directly linked to a sudden rise in adrenaline hormones during physical exertion.

Structural Heart Disease:

• Acquired: Conditions such as arterial blockages (coronary artery disease), weakened heart muscle (heart failure), valvular problems, and congenital defects are classified as structural issues but are not necessarily inherited. They can primarily cause sudden cardiac death but do not require family screening.
• Inherited: Structural heart diseases that cause sudden cardiac death and necessitate family screening include hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), and genetic cardiomyopathies.

Other Conditions:

• Aortic Dilatation: Sudden cardiac death may occur if the aorta is torn, causing internal bleeding. This condition may be inherited (especially with associated syndromes like Marfan Syndrome) or acquired, with contributing factors such as smoking and high blood pressure.
• Pulmonary Embolism: Pulmonary embolism is a blockage in the pulmonary artery and considered a common non-cardiac cause of cardiac arrest and sudden cardiac death, and it is usually acquired (e.g., pregnancy, autoimmune diseases, surgeries, or immobility).
• Brain Hemorrhage: Severe brain hemorrhage may expose the patient to the risk of sudden cardiac death if there is no urgent surgical