Reflex-related causes: neurally mediated syncope and postural syncope.
Cardiovascular cause, or cardiac syncope, including arrhythmia and organic cardiovascular disease. These diseases directly affect patients' cardiovascular systems, including decreased blood pressure, reduced cardiac output, diminished oxygen supply, and sustained cerebral circulation insufficiency, resulting in potential life threats to the patients.
Nearly 40% of patients suffer from unexplained syncope. However, they have to pay high costs of repeat medical treatment in hospitals. Therefore, syncope has imposed a heavy economic burden on individuals and society.
Pre-syncope symptoms include sudden dizziness, trance, blurred vision, vision disturbance, and weakness of limbs. After that, patients lose consciousness and fall to the ground, but recover within seconds or minutes, standing up and walking as usual. Some may feel generalized weakness within half an hour of the onset of the syncope. In many cases, the patients feel weak all over the body instead of falling, without any loss of consciousness, or the patients who have repeatedly experienced the same symptoms before can get rid of them quickly after squatting in a timely manner. During syncope, patients show slower or faster heart rate, lower blood pressure, pallid face, and probable occurrence of cold sweat. Syncope usually attacts patients when they are standing up or sitting down. However, if it occurs when lying, patients should further check whether they are attacked by cardiovascular diseases, like arrhythmia, transient cerebral ischemic, or epilepsy.
From the epidemiological perspective, the overall incidence of syncope is 7.5%, of which 18% to 33% are caused by cardiac diseases.
From the perspective of individuality, 40% of people will suffer at least one syncope in their lifetimes. Patients with cardiac syncopes are at greater risk of sudden cardiac death, with a mortality of more than 10% within six months of the onset of the symptoms. Clinical data also show that syncope contributes to 10% of the elders' falls.
Cardiac syncope may be the only pre-symptom of sudden cardiac death, while arrhythmia can be shown in the form of bradycardia and tachycardia. Meanwhile, patients with cardiac syncope often have poor prognoses and are at doubled risk of death. In this way, they need an early diagnosis of the causes.
Patients should identify the causes of syncope and seek targeted therapeutic solutions.
With an implantable cardiac monitor (ICM), doctors can monitor the symptoms and cardiac rhythm-related ECG during syncope for 1 to 3 years and identify the causes of syncope with higher accuracy from 43% to 88%.
Syncope is a collection of clinical manifestations of the sudden loss of consciousness and body control caused by whole-brain ischemia. It is usually a temporary loss lasting less than 20 to 30 seconds with a quick, complete, and automatic recovery. Syncope is generally caused by a transient ischemic attack.
