Syncope
Syncope is a brief loss of consciousness accompanied by loss of skeletal muscle tone. It is often accompanied by falling or slumping to the ground. The patient himself regains consciousness in a short time without the need for external intervention. It is necessary to distinguish from syncope the so-called collapsed state, where there is only a fall or slump but no loss of consciousness, and the brief sensation of fainting without loss of consciousness or collapse, which is called vertigo or presyncope.
The most common cause of syncope is a transient decrease in blood pressure. The body has natural mechanisms to constantly maintain blood pressure sufficient to circulate blood to the brain. The body contracts the arteries in the muscles and the blood pressure increases. This is important when standing up, standing or sitting for long periods of time and especially in warm or unventilated environments. If these mechanisms are less functional, syncope can occur in these cases. In this case, the patient often feels a feeling of weakness as a warning sign before losing consciousness, but even this warning may not always be present or remembered by the patient after waking up. Syncope due to a reduction in blood pressure is not in itself life-threatening and there is always a recovery of consciousness. Syncope due to lowering of blood pressure includes so-called orthostatic syncope, which occurs when standing up or shortly afterwards. In addition, so-called neurocardiogenic syncope (sometimes also called reflex or vasovagal syncope), when the drop in blood pressure and syncope occurs suddenly without an apparent triggering factor, purely due to a disturbance in blood pressure regulation. Furthermore, this group of syncope includes situational syncope, provoked by typical blood pressure lowering situations such as pain, blood sampling, coughing or urination.
Hot days and lack of fluids increase the risk of syncope due to reduced blood pressure
A less common but more severe type of syncope is the so-called cardiac syncope. This occurs when the main cause is a malfunction of the heart. It most often occurs when the heart stops or slows down temporarily or when the heart beats abnormally fast. It can occur when the aortic valve narrows and blood cannot flow sufficiently out of the heart, or in pulmonary embolism when blood cannot flow through the lung. After syncope has taken place, all these dangerous cardiac causes must be ruled out.
Heart rhythm disorders that can cause syncope. Arrows indicate atrial contractions, the symbol "+" indicates a contraction of ventricles. A) Sinus arrest - atrial contraction is arrested, but the transfer to the ventricles is intact, B) Atrioventricular block of II degree - atrial contraction is preserved, but there are failures of transfer to the ventricles and the contraction of ventricles is slower, C) Atrioventricular block of III degree - atrial contraction is preserved but does not transfer to the ventricles and the ventricles contract in a slow rhythm of their own.
Other even less common causes of syncope are then extra-cardiac causes such as epilepsy.
EEG (electroencephalography) in a patient with generalized epileptic seizure
If syncope occurs, it is necessary to assess in particular the situation in which it occurred, whether the patient experienced any symptoms before the loss of consciousness, what was the surrounding environment and the overall situation and whether the episode occurred standing, sitting or lying down. The presence of convulsions or trauma does not always imply a cardiac or neurological cause, and syncope from a drop in blood pressure can occur. Assessment of the situation and the course of the episode will help tentatively to determine the cause of the syncope, but further investigation is necessary to exclude serious conditions. The basic investigations are blood pressure measurement and 12-lead ECG recording. The ECG waveform will reveal persistent rhythm disturbances such as sinus node dysfunction, AV block or ventricular tachycardia. However, with normal findings on the resting ECG, a transient heart rhythm disturbance that led to syncope but subsequently resolved cannot be ruled out. We also look for signs of impending heart rate deceleration on the ECG curve, such as left bundle branch block or bifascicular block.
Electrocardiographic examination (ECG)
Basic examination of syncope, can detect persistent heart rhythm disturbances
Echocardiography is another important examination in the search for the cause of syncope. This will help detect a valvular defect, especially a narrowing of the aortic valve. It will also help to assess left ventricular function. In the case of impaired contractility, a serious arrhythmia such as ventricular tachycardia or ventricles fibrillation that has spontaneously terminated and thus only manifests as syncope cannot be ruled out as a cause of syncope. Echocardiography will also express suspicion of pulmonary embolism and can rule out rare causes such as pericardial effusion or oppression of the heart compartments by, for example, a tumour.
Transthoracic echocardiography (TTE)
It is one of the basic examinations of patients with syncope. It can assess the size of the heart compartments, the function of the valves and the stiffness of the cardiac ventricles.
If investigations such as BP measurements, ECG and echocardiography fail to identify the cause, or if symptoms of syncope such as convulsions are suspected, neurological examination including brain imaging to exclude tumour involvement in particular and EEG or electroencephalography to help diagnose epilepsy are added. Long-term ECG monitoring is also performed using 1-7 day Holter monitoring or an adhesive ECG recorder. It is also possible to insert a permanent ECG monitor, the so-called episodic arrhythmia recorder, into the subcutaneous tissue of the chest with a small surgical procedure. This implantation procedure is performed when previous investigations have not led to a determination of the cause and the syncope continues to recur. As part of the search for low blood pressure, 24-hour ambulatory blood pressure monitoring, or pressure Holter, can also be performed.
Holter ECG monitoring
Continuous ECG monitoring for 24 hours to 7 days. The recording is then evaluated by a physician.
Implantable Loop Recorder (ILR)
Implanted into the subcutaneous tissue of the chest under local anaesthesia from a 5 mm incision. The battery has a lifetime of 2-3 years. The device communicates remotely with the doctor's office.
ABPM - ambulatory blood pressure monitoring (BP Holter)
Blood pressure is measured at intervals of 1 hour for 24 hours.
If all the examinations are normal, a head-up tilt test (HUT) can be added. The subject is first lying on the bed, then tilted to a near vertical position and left in this position for 45 minutes with ECG monitoring and regular blood pressure measurements. This position is demanding for the body to maintain blood pressure and may provoke low blood pressure in susceptible subjects, thus indirectly confirming neurocardiogenic syncope.
Head up tilt test (HUT)
Tilt-bed examination used to confirm the diagnosis of neurocardiogenic syncope.
If serious causes of syncope, such as rhythm disturbances, valvular defects or pulmonary embolisation, are excluded, it is most likely to be syncope due to low blood pressure. In elderly patients taking a range of drugs to lower blood pressure, a so-called orthostatic test can be performed - measure blood pressure lying down and then measure blood pressure standing up after 5 min of lying down. The fall in standing blood pressure should be no more than 20/10 mmHg. In these patients, it is necessary to reduce the dose or completely discontinue some of the blood pressure lowering drugs. In the home environment, blood pressure should preferably be within 135/85 mmHg and this value is more important than blood pressure measured in the doctor's office, where values are often falsely higher.
In younger patients, after ruling out rarer, more severe causes of syncope, the most likely cause is neurocardiogenic syncope. Syncope in this case is caused by a disturbance in the regulation of blood pressure. Treatment is very difficult and is based mostly on regimen measures such as sufficient fluid intake, avoidance of risky situations such as long periods of standing or sitting, especially in warm or unventilated environments. If the patient recognises the warning signs of loss of consciousness, syncope can be prevented by lying flat, elevating the lower limbs or, if the situation does not allow it, by, for example, contracting the muscles of the lower limbs and thereby increasing venous return to the heart. In the case of multiple difficulties, the drug midodrine can be used to increase blood pressure by retaining fluids in the body. In the course of life, neurocardiogenic syncope tends to subside, the difficulties become less severe and may disappear completely without treatment.
After the syncope has taken place, it is necessary to decide on the ability to drive. If the syncope is neurocardiogenic (vasovagal) in nature, the ability to drive motor vehicles is not impaired. If the neurocardiogenic syncope recurs, it is advisable to wait 1 month for a private driver and 1 year for a professional driver. If the syncope is of unclear origin and is not typical of neurocardiogenic syncope, it is advisable to wait 1 month for personal driving and 1 year for professional driving. If a cause is identified that is subsequently removed, for example by implantation of a permanent pacemaker, the waiting period is 1 week for private drivers and 1 month for professionals.
Expert opinion of the Czech Society of Cardiology from 2012 on the assessment of driving ability after syncope https://e-coretvasa.cz/pdfs/cor/2013/03/13.pdf
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Decrease in blood pressure
Orthostatic hypotension
Neurocardiogenic (vasovagal) syncope
Situational syncope
Heart rhythm disorder
Sick sinus syndrome
Atrioventricular (AV) blockade
Ventricular tachycardia
Fibrillation of ventricles
Restriction of blood flow
Aortic stenosis
Pulmonary embolism
Neurological causes
Epilepsy
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Interview with the patient about the course of the episode
Blood pressure
Quiet
24 hour monitoring
ECG
Quiet
Holter ECG (1-7 days)
Episode recorder
Sticker
Implantable
Echocardiographic examination
Evaluation of left ventricular stiffness
Evaluation of valve function
Exclusion of pulmonary embolism
Neurological examination
Brain imaging methods
EEG
Inclined plane test
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Neurocardiogenic syncope
Regime measures
Midodrine
Orthostatic hypotension
Reduction or discontinuation of any treatment for high blood pressure
Enough fluids
Situational syncope
Avoiding or treating trigger causes
Aortic stenosis
Aortic valve replacement by catheterization or surgery
Slowing of the heart rhythm
Permanent pacemaker implantation
Ventricular tachycardia or ventricles fibrillation
Treatment of possible coronary disease
Catheter ablation
Pulmonary embolization
Drugs to reduce blood clotting during hospitalization
Epilepsy
Antiepileptic therapy
Structural diseases of the brain
Targeted neurosurgical treatment
