What are the most common causes of cardiac syncope?

Cardiogenic syncope is a common disease that is caused by a sudden decrease in the heart's blood output, resulting in transient syncope. If it is not treated effectively in time, the chance of being fatal can be very high. From a clinical perspective, patients do not have obvious symptoms before the disease occurs, but suddenly faint when the disease occurs, and often suffer from falls or incontinence. This must be handled correctly.

1. Common causes of cardiac syncope

Cardiogenic syncope is a brief loss of consciousness caused by a sudden decrease in cardiac output, which leads to a transient decrease in cerebral blood flow. Although it is relatively rare, it often has fatal consequences. If the cause can be found, most cases can be effectively treated.

Causes of cardiac syncope include arrhythmias and organic cardiopulmonary diseases. Arrhythmias may occur secondary to organic heart disease, some of which can be directly or indirectly displayed by echocardiography. For example, ventricular premature beats or ventricular tachycardia may occur in the presence of intramural space-occupying lesions in the ventricular myocardium. Acute thrombotic pulmonary embolism can also induce arrhythmias through vagal nerve reflexes. For patients with suspected organic cardiopulmonary disease, echocardiography can help confirm or exclude cardiac causes of syncope. The European guidelines for the diagnosis and treatment of syncope point out seven main causes of cardiogenic syncope: "organic heart disease or cardiopulmonary disease."

2. Clinical features of cardiogenic syncope

The prodromal symptoms of patients with cardiac syncope are often not obvious, and the attacks are generally unrelated to body position. There are many cases of falls and even incontinence. Cardiogenic syncope often occurs during stress or fatigue. Children with known heart structural abnormalities, a history of arrhythmias, or sudden death in the family may have cardiogenic syncope. When children faint, they may be pale, cyanotic, and have difficulty breathing; their heart rate and rhythm may change significantly; they may also have convulsions; and they may have edema and clubbing of the fingers, indicating cardiac syncope. All syncope associated with exercise or exertion should be followed by an electrocardiogram. Medical history, physical examination, and electrocardiogram can provide a preliminary estimate of the risk of cardiac syncope and sudden death, and are the basis for determining whether the child needs hospitalization. Echocardiography is rarely useful in patients whose medical history, physical examination, and electrocardiogram do not suggest cardiac syncope. However, echocardiography should be performed for patients with exercise-related syncope, syncope during swimming, heart murmurs, or a family history of sudden death or cardiomyopathy. For patients with syncope related to exercise, exercise testing, electrocardiogram, and blood pressure monitoring are helpful.