SYNCOPE Diagnosis and therapy

The diagnostic work-up of syncope patients often raises the question of how much diagnosis is necessary and what examination methods are really needed. To save time, specialists recommend focusing on determining whether the syncope may be caused by a cardiac problem - a question answered quite easily in many cases.

Karl Eberius MD, European Hospital's new correspondent, discussed advice for physicians with Professor Andreas Schuchert, principal author of the German Society of Cardiology's official statement on syncope

Karl Eberius
Karl Eberius

According to Professor Andreas Schuchert, a basic diagnostic work-up for every syncope case consists of three steps: the first a thorough anamnesis, followed by a brief physical examination and an ECG. ‘Further measures are only necessary either if no specific type of syncope can be determined or if there are indications of their being caused by a cardiac problem.’ Only cardiac syncope shows a clearly raised death rate (18-33% annually) depending on the study, he adds

What is relevant in medical history?
Syncope caused by cardiac disorders can often be identified during the anamnesis by asking just a few questions, importantly whether the syncope occurred during physical effort, which, the professor points out, is primarily an indication of aortic stenosis or hypertrophic obstructive cardiomyopathy. Another question: whether there was chest pain before or after the syncope, which may indicate coronary ischaemia, the professor explains. The physician should also check for previous arrhythmia or other cardiac disease. ‘If, for example, there has been a heart attack in the past, cardiac syncope should be assumed until there is evidence to the contrary,’ says Prof Schuchert, who also considers the family’s medical history an important indicator. For example, the sudden death of a young relative from cardiac causes may indicate hereditary heart disease, e.g. Brugada syndrome – rare but it should be considered.

Heart sounds
The basic diagnostic physical work-up often only requires a few steps. ‘The first is auscultation of the heart, during which pathological sounds of any kind must be assessed as warnings of cardiac syncope,’ Prof Schuchert emphasises. The neck vessels should also be auscultated for stenosis of the carotid artery. The physician should also listen very carefully for an irregular heartbeat or a heart rate below 50 or above 100 beats a minute, which may indicate AV block or atrial fibrillation as the cause of syncope. ‘The most important alarm signals are evidence of cardiac insufficiency – for example, the legs are oedematous or there are rattling sounds from the lungs or a congested liver is detectable more than two finger widths below the rib cage,’ he reminds us. ‘The combination of cardiac insufficiency and syncope indicates a critically raised risk of mortality and therefore needs to be immediately diagnosed.’

Vasovagal events
If that basic procedure indicates no cardiac cause, the physician can focus on determining the actual type of syncope – often possible by looking at the medical history. ‘A vasovagal attack, the most frequent kind of syncope, must always be assumed, for example, when typical symptoms preceded the fainting attack: nausea, sweating, dizziness, drowsiness, weakness, abdominal discomfort or blurred vision,’ he explains. ‘Similarly when fainting followed a long period of standing tensely or the attack followed pain, emotional stress, anxiety or procedures like having blood taken.’

Fainting during defecation
Situational syncope must be assumed if loss of consciousness occurs while urinating, defecating, coughing or vomiting. ‘Unlike the vasovagal attack, the trigger in these cases is not a diffuse sensation, like anxiety or pain, but a clearly defined situation. Furthermore situational syncope typically occurs more suddenly and without any warning.’
Orthostatic syncope occurs when standing up from lying down or sitting. Unlike a vasovagal attack, an orthostatic syncope typically does not occur after standing for a long period but immediately after the change in position.
A drug-induced syncope should be considered if the blood pressure (BP) has been too drastically modified in hypertensive patients. On the other hand, if fainting occurs when turning the head, for example while shaving or looking over one’s shoulder in a car, carotid sinus syndrome should be considered.

Additional examinations
Depending on the results from the basic diagnosis, various other investigations may be recommended to clarify the type of syncope. If the medical history indicates an orthostatic syncope, for example, diagnosis can be confirmed by the Schellong test, in which the BP taken after five minutes in the lying position is compared to that taken after subsequently standing up. The diagnosis is confirmed when the systolic value after standing up falls below 90 mmHg or is more than 20 mmHg below the measurement taken when lying down. Prof Schuchert points out that, if the previously ascertained medical history indicates vasovagal syncope, carotid sinus syndrome or situational syncope, the Schellong test is unnecessary. Moreover, tilt tests may be useful, for example when vasovagal syncope is suspected but the medical history does not unambiguously indicate this. However, the predictive value of tilt tests is increasingly challenged.

Laboratory tests of doubtful benefit
The professor believes laboratory tests are almost always unnecessary for clarifying syncope – particularly true for the determination of Hb levels, a test frequently performed due to a lack of other ideas, but which is actually only necessary if anaemia is clinically indicated. ‘In 99% of syncope diagnoses no laboratory tests are required.’
The same applies to carotid Doppler examinations, which are only indicated when sounds of stenosis can actually be heard on auscultation of the vessels of the neck. ‘Otherwise the probability of syncope caused by carotid disorders should be ignored.’

Vasovagal syncope can often be treated effectively by the simplest methods. Counter pressure manoeuvres are particularly useful in many cases, and in recent years have become a highly popular way to prevent decreasing BP without complications.
Before beginning treatment for vasovagal attacks, specialists recommend sufficient time is given to explain the therapy. ‘Patients should know that fainting attacks are not a symptom of a dangerous disease of an organ,’ Prof Schuchert emphasises.’ When they know this they can then react more calmly to the fainting, which for many is already a great relief.’
During a consultation the typical trigger factors for syncope should be addressed. ‘Someone who tends to have syncope attacks in narrow, overheated spaces should avoid department stores. And a person who has problems when asked for a blood would be wise to lie down before the procedure,’ he advises, deploring the omission of these simple but important recommendations.
Counter pressure manoeuvres are in many cases a very effective aid, widely used in clinical practice to counteract the fall in BP in a vasovagal attack. Counter pressure manoeuvres require a hand size rubber ball, simply carried in a pocket or bag. If a fainting attack approaches, in vasovagal attacks not frequently heralded by typical symptoms, e.g. nausea, dizziness or drowsiness, one squeezes the ball as hard as possible. As a result of muscle contraction, the sympathetic system is evidently activated, producing constriction of the peripheral blood vessels, thus often preventing the fall in BP causing syncope in the preliminary stage.
Alternatively one can perform the manoeuvre shown in the image. Simply clasp your hands together with arms at about chest height in front of your body and try to pull your arms apart while not loosening your clasp. In both counter pressure manoeuvres muscles contract for as long as it takes for the signals of the attack to disappear.

Medication can also be useful to treat some vasovagal cases, particularly when other therapies have failed and syncope continues to occur. ‘The drug of choice is the alpha antagonist midodrine. At a dose of 3 x 10 mg/d this effectively raises the BP, and in almost all cases the drug avoids recurrence,’ the professor says. However, it is not suitable for every patient because it potentially increases the BP. This applies particularly to the elderly, whose BP compared to that of younger people is often already raised. Additionally, since this drug must be taken three times a day, many patients have compliance problems.
If patients suffering vasovagal attacks are already hypertensive, beta-blockers can also be a useful alternative. Although not recommended by the ESC due to unproven benefit in vasovagal attacks, studies in recent years in patients aged 40+ indicate positive effects, so for this age group they are often to be recommended, he points out. Other drug alternatives, including selective serotonin re-uptake inhibitors, e.g. paroxetine, are being discussed, but Prof Schuchert recommends their very careful use due to lack of long-
term data.
Furthermore, in cases of vasovagal attacks the physician should check whether the patient is taking anti-hypertensive medication, which might cause the syncope and which could be reduced or discontinued.
In some cases a cardiac pacemaker may be an option. ‘Such an implant is indicated if, for example, an event or loop recorder, which records the ECG over several months or even years, shows that asystoles are the cause of the fainting attacks,’ he points out.

Fluids and physical exercise
Often, various lifestyle changes are also recommended to avoid vasovagal attacks: more fluid intake, more salt in the diet and more physical exercise. However, scientifically, he points out their benefit has not been confirmed, which does not mean such changes are not worth a try in sufficiently motivated patients.
For many specialists, less recommendable is ‘tilt training’, in which patients stand leaning against a wall, depending on the treatment plan, say for half an hour daily, to train their circulatory systems. Theoretically it produces good results, the professor says, ‘But it’s time-consuming and thus compliance is very poor.’

Orthostatic syncope – If loss of consciousness occurs directly after standing up from having been lying down or sitting, this indicates orthostatic syncope. The most important recommendation of Prof Schuchert is simply to stand up more slowly so that the cardiovascular system can adapt better to the body being upright. “Support hose, the sympathomimetic drug etilefrine or the mineral corticosteroid fludrocortisone can also be helpful.”
Situational syncope – Mostly occurring during micturation, defecation, coughing or vomiting, in many cases this is not easy to treat and there are no proven evidence-based measures. ‘Any therapy that is also used for vasovagal attacks is worth a try,’ Prof Schuchert says, adding that many patients are helped by support hose or etilefrine.
- Diagnosis is the priority in vasovagal attacks. People affected should be aware that the loss of consciousness does not indicate a dangerous disease of any organ.
- It is important to avoid factors triggering syncope.
- Counter pressure manoeuvres (e.g. squeezing a rubber ball or pulling clasped hands apart) have proved valuable to counteract fall in BP during vasovagal attacks.
- Lifestyle changes can be tried in motivated patients, e.g. increasing physical exercise, fluid and salt intake.
- For vasovagal attacks, midodrine is the first drug of choice (3 x 10 mg/d).
- The benefits of selective serotonin re-uptake inhibitors have not been definitively clarified.
- Support hose, etilefrine and fludrocortisone can be useful for orthostatic syncope.
- There is no evidence-based drug to treat situational syncope.


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