From the Guidelines
Pre-syncope with tachycardia is a condition that requires prompt medical evaluation to determine the underlying cause, and initial management includes sitting or lying down to prevent falls, staying hydrated, and seeking medical attention. This condition is characterized by near-fainting symptoms accompanied by an abnormally fast heart rate, typically over 100 beats per minute. According to the 2021 study by the American College of Radiology 1, the mainstay of syncope and presyncope assessment is a detailed history and physical examination, including measurement of postural changes in blood pressure to diagnose orthostatic-related syncope.
Some common causes of pre-syncope with tachycardia include:
- Dehydration
- Anemia
- Medication side effects
- Heart rhythm disorders like supraventricular tachycardia
- More serious cardiac conditions
For recurrent episodes, a cardiologist may prescribe medications such as:
- Beta-blockers (like metoprolol 25-100mg daily) to control heart rate
- Calcium channel blockers (like diltiazem 120-360mg daily) to control heart rate In some cases, catheter ablation might be recommended for certain arrhythmias. Patients should avoid triggers like caffeine, alcohol, and dehydration. The connection between pre-syncope and tachycardia involves reduced blood flow to the brain when the heart beats too quickly and inefficiently, leading to symptoms like lightheadedness, dizziness, and visual changes.
As stated in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1, pre-syncope (near-syncope) is defined as the symptoms before syncope, which could include extreme lightheadedness, visual sensations, and variable degrees of altered consciousness without complete loss of consciousness. Anyone experiencing these symptoms should seek medical attention rather than self-diagnosing, as proper treatment depends on identifying the specific underlying cause.
From the Research
Pre-Syncope Tachycardia
- Pre-syncope is a condition that may precede syncope, characterized by symptoms such as dizziness, lightheadedness, and palpitations 2.
- Tachycardia, or an abnormally fast heart rate, may be a contributing factor to pre-syncope 3.
- The causes of pre-syncope and syncope are diverse, but may include vasovagal or orthostatic origins, as well as cardiac structural disease or channelopathies 3.
Treatment and Management
- Physical counter-pressure maneuvers (PCM) may be beneficial in preventing syncope during acute episodes of pre-syncope, although the evidence is limited and of low certainty 2.
- Beta-blockers, such as metoprolol, have been studied as a potential treatment for vasovagal syncope, but the evidence is mixed and their effectiveness in improving quality of life is unclear 4, 5.
- Metoprolol has been shown to be effective in treating supraventricular tachycardia, a type of abnormal heart rhythm that may contribute to pre-syncope 6.
Symptoms and Outcomes
- Pre-syncope and syncope can have a significant impact on quality of life, particularly if they are recurrent 5.
- The prevention of syncope is an important goal, as it can reduce the risk of accidents and injuries, as well as improve overall quality of life 2, 3.
- Blood pressure and heart rate are important vital signs to monitor in patients with pre-syncope, as they can provide insight into the underlying causes of the condition and guide treatment decisions 2.