Supraventricular Tachycardia: Symptoms, Types, Causes and Treatment

Supraventricular tachycardia (SVT) is a common heart rhythm disorder that can affect all age groups, causing episodes of rapid heartbeat that originate above the ventricles. While often not life-threatening, SVT can cause significant discomfort, anxiety, and in some cases, disabling or even potentially dangerous symptoms. Understanding the symptoms, types, causes, and treatments of SVT is essential for patients and healthcare providers alike. This article provides a comprehensive, evidence-based overview of SVT, synthesizing the latest research to help you better recognize and manage this condition.

Symptoms of Supraventricular Tachycardia

SVT symptoms can range from barely noticeable to severe and disruptive, often impacting quality of life. Some patients experience only fleeting episodes, while others face frequent or prolonged symptoms that interfere with daily activities. Timely recognition of these symptoms is critical for accurate diagnosis and effective management.

Symptom	Frequency/Severity	Additional Notes	Source(s)
Palpitations	Very common (~96%)	Often described as sudden, rapid onset	1 4 5 9
Dizziness	Common (19–75%)	May be associated with syncope	1 2 4
Chest Pain	Common (up to 47%)	Can range from mild to severe	2 4
Shortness of Breath (Dyspnea)	Common (38–47%)	Frequently reported	1 4
Syncope	Notable (20–26%)	Typically preceded by palpitations	1 4
Fatigue	Common post-event	May persist after tachycardia episode	4 5
Sweating	Less common (18%)	May accompany acute episodes	4
Unusual Symptoms	Variable	GI, neurological, psychosomatic possible	4

Table 1: Key Symptoms

Overview of Common SVT Symptoms

Palpitations are the hallmark symptom of SVT, described as a sudden, rapid, and regular pounding or fluttering of the heart. Many patients can pinpoint the abrupt beginning and end of these episodes, which distinguishes SVT from other arrhythmias or anxiety-related symptoms. Palpitations were reported by up to 96% of patients in some studies, making them the most reliable indicator of SVT 1 4 5 9.

Dizziness and lightheadedness frequently occur during episodes, particularly when the heart rate is very high (≥170 beats/min), sometimes leading to syncope (fainting) 1 2 4. Syncope is more likely when the SVT is faster or prolonged and is typically preceded by palpitations 1.

Chest pain is another common symptom, experienced by roughly half of SVT patients 2 4. While often benign, it can cause significant anxiety, especially in those concerned about heart disease.

Shortness of breath (dyspnea) is reported by approximately 38–47% of patients, and may be accompanied by a sensation of pressure or tightness in the chest 1 4.

Fatigue and lightheadedness are often noted after an episode, sometimes persisting for hours 4 5. Sweating and other autonomic symptoms may accompany acute attacks 4.

Unusual symptoms can include gastrointestinal disturbances, neurological sensations, and psychosomatic complaints, often complicating the diagnostic process 4.

Symptom Impact and Quality of Life

• Many patients experience significant anxiety and lifestyle changes due to the unpredictable and sometimes disabling nature of SVT 5.
• Misdiagnosis with anxiety or panic disorder is common, especially in women and younger patients, due to overlapping symptoms 2 5.
• Infrequent, brief episodes may require little or no treatment, but frequent or severe symptoms often necessitate intervention 5 8.

Types of Supraventricular Tachycardia

SVT is not a single condition but an umbrella term for several specific arrhythmias arising above the heart's ventricles. Understanding these types is crucial for accurate diagnosis and targeted treatment.

Type/Mechanism	Description/Pathway	Prevalence/Notes	Source(s)
AVNRT	Reentry circuit in AV node	Most common SVT	1 2 6 12
AVRT (e.g., WPW)	Reentry via accessory pathway	2nd most common	1 2 6 9
Atrial Tachycardia	Automatic focus in atria	Less common	1 2 6 9
Atrial Flutter	Macro-reentrant circuit in atria	Variable, not always SVT	1 6 7 10
Multifocal/Other	Multiple atrial foci or rare forms	Less frequent	7 10

Table 2: Main SVT Types

The Major SVT Types Explained

Atrioventricular Nodal Reentrant Tachycardia (AVNRT)

• Mechanism: A reentrant circuit forms within the AV node, using dual pathways (fast and slow) 6 12.
• Prevalence: Most common type of SVT in adults and older children 1 2.
• Symptoms: Similar profile to other SVTs; may include palpitations, dizziness, and syncope 1.
• Treatment: Responds well to vagal maneuvers, adenosine, and is highly curable with catheter ablation 12.

Atrioventricular Reciprocating Tachycardia (AVRT)

• Mechanism: Extra pathway (often called an accessory pathway) connects atria and ventricles, as in Wolff-Parkinson-White (WPW) syndrome 1 2 6 9.
• Prevalence: Second most common in adults; more frequent in children 1 2 11.
• Symptoms: Similar to AVNRT; WPW may have ECG features (delta wave) 10.
• Treatment: Catheter ablation is often curative, especially if WPW is present 7 9.

Atrial Tachycardia

• Mechanism: A single abnormal focus in the atria causes rapid firing, sometimes with AV block 6 9.
• Prevalence: Less common than AVNRT or AVRT 1.
• Symptoms: May be less abrupt in onset/termination 6.
• Treatment: May respond to antiarrhythmics; ablation can be considered 7.

Atrial Flutter

• Mechanism: Large, organized reentrant circuit in the right atrium, often related to anatomical barriers 6 10.
• Prevalence: Variable, often seen with structural heart disease or after ablation for atrial fibrillation 7 10.
• Symptoms: Can cause rapid, regular palpitations and risk of stroke 7.
• Treatment: Ablation and anticoagulation if indicated 7.

Other and Rare Forms

• Multifocal Atrial Tachycardia: Multiple foci, often in elderly or those with lung disease 7 10.
• Sinus Tachycardia (inappropriate): Not typically included in SVT management guidelines 7.

Diagnosis by Type

• ECG during tachycardia is critical for distinguishing the mechanism, but clinical history is also highly valuable 2 5 10.
• Certain ECG findings (e.g., delta wave in WPW, flutter waves in atrial flutter) can guide diagnosis 10.
• Pediatric SVT may have some differences in symptom profile and subtype distribution, often requiring specialist input 3 11.

Causes of Supraventricular Tachycardia

The root causes of SVT vary, with most cases linked to electrical abnormalities in the heart's conduction system rather than structural defects. Understanding these mechanisms can clarify why SVT occurs and help guide prevention and management.

Cause/Trigger	Description/Mechanism	Population/Notes	Source(s)
Reentry Circuits	Abnormal electrical loop (AVNRT, AVRT)	Most adults/children	2 6 9 10
Accessory Pathways	Extra conduction pathway (WPW)	Congenital; all ages	2 6 9 10
Abnormal Automaticity	Spontaneous firing in atria	Atrial tachycardia	6 9
Triggers	Stress, caffeine, alcohol, stimulants	All ages	5 9
Medications	Digitalis toxicity (esp. atrial tachy)	Elderly, heart disease	6 9
Structural Heart Disease	Rare in SVT	Some risk in elderly	2 9
Genetic Factors	Familial syndromes, WPW	Children, young adults	11

Table 3: Main Causes and Triggers

Mechanisms Behind SVT

Reentry Circuits

• AVNRT and AVRT are classic examples of reentry tachycardias—the most common SVT mechanism. An electrical impulse loops through a circuit, reactivating tissue and causing rapid heartbeats 2 6 9.
• In AVNRT, the circuit is within the AV node, while in AVRT it involves an accessory pathway connecting the atria and ventricles 6 10.

Accessory Pathways

• Wolff-Parkinson-White (WPW) syndrome is the classic accessory pathway condition, where an extra electrical connection can precipitate SVT 2 6 9 10.
• These pathways are often congenital but may not manifest until adolescence or adulthood 11.

Abnormal Automaticity

• Atrial tachycardia results from a spot in the atria firing off impulses too quickly, sometimes associated with digitalis toxicity or atrial scarring 6.

Triggers and Risk Factors

• Episodes can be triggered by stress, lack of sleep, caffeine, alcohol, stimulants, or certain medications 5 9.
• Genetic predisposition is important, especially in pediatric SVT and familial WPW 11.
• SVT is rare in people with structural heart disease, but risk increases with age and comorbidities 2 9.

Special Considerations

• Children: SVT may present with subtle symptoms and can be more likely due to congenital pathways 3 11.
• Elderly: More likely to have atrial tachycardia or flutter related to underlying heart disease 7 10.
• Medications: Digitalis toxicity is a notable cause of SVT, especially in older adults 6.

Treatment of Supraventricular Tachycardia

Managing SVT involves both acute interventions to stop an episode and long-term strategies to prevent recurrences. The choice of treatment depends on the type of SVT, symptom severity, patient preference, and underlying health.

Treatment	Indication/Use	Notes on Effectiveness or Role	Source(s)
Vagal Maneuvers	Acute termination	First-line, noninvasive, can be self-administered	8 13 15
Adenosine	Acute termination	High efficacy, rapid effect, short-lived side effects	8 14 15
Beta-Blockers / Calcium Channel Blockers	Acute and long-term	Useful if vagal maneuvers/adenosine fail or for maintenance	2 8 9
Antiarrhythmics	Long-term prevention	Reserved for select cases, managed by cardiologist	2 7 9
Catheter Ablation	Curative for most SVT types	First-line for recurrent/persistent SVT, high success	5 7 8 9 12
Electrical Cardioversion	Acute hemodynamic compromise	Emergency only	15
Anticoagulation	Atrial flutter with stroke risk	Follows atrial fibrillation guidelines	7

Table 4: SVT Treatment Approaches

Acute Management

Vagal Maneuvers

• Valsalva maneuver (bearing down) and carotid sinus massage stimulate the vagus nerve, which can interrupt SVT 13 15.
• A modified Valsalva with postural change nearly triples the success rate compared to standard technique 13.
• These are safe, first-line options and can even be taught for home use 13.

Adenosine

• Administered intravenously, adenosine blocks the AV node transiently and can terminate most AVNRT and AVRT episodes within seconds 14 15.
• Side effects (flushing, chest discomfort) are brief and not dangerous 15.
• Should not be used in irregular, wide-complex tachycardias (possible pre-excited atrial fibrillation) 14.

Beta-Blockers and Calcium Channel Blockers

• Useful for termination if vagal maneuvers and adenosine fail, or as maintenance therapy 2 8 9.
• Should be used cautiously and typically under specialist guidance 2 9.

Electrical Cardioversion

• Reserved for unstable patients with severe symptoms or hemodynamic compromise 15.

Long-term Management and Prevention

Catheter Ablation

• Curative in most cases: Catheter ablation targets the abnormal pathway or focus, with a success rate of >95% for AVNRT and AVRT 5 7 9 12.
• Low risk of complications (e.g., heart block <1%) 9 12.
• First-line for patients with frequent, severe, or lifestyle-limiting SVT, or those who prefer to avoid long-term medication 5 7 8.

Pharmacologic Therapy

• Beta-blockers, calcium channel blockers, and class Ic/III antiarrhythmics may be used if ablation is not possible or desired 2 7 9.
• Long-term antiarrhythmic use is less favored due to side effects and limited efficacy, and is typically managed by a cardiologist 2 7.

Anticoagulation

• Important for atrial flutter patients at risk of stroke, following atrial fibrillation guidelines 7.

Special Considerations

• Children: Management often mirrors that of adults, with an emphasis on accurate diagnosis and individualized therapy 3 11.
• WPW Syndrome: Early referral for electrophysiology evaluation and ablation is recommended due to risk of sudden arrhythmia 2 7 9.
• Asymptomatic patients: May not require therapy unless high-risk features are present (e.g., competitive athletes, certain occupations) 7.

Conclusion

SVT is a common, often benign, but potentially disruptive arrhythmia that can significantly affect quality of life. Prompt recognition and understanding of the different types and treatments can ensure the best outcomes for patients.

Key Takeaways:

• SVT is characterized by sudden-onset palpitations, dizziness, chest discomfort, and sometimes syncope or fatigue 1 4 5 9.
• The main types are AVNRT, AVRT (including WPW), atrial tachycardia, and atrial flutter, each with distinct mechanisms and management strategies 1 2 6 7.
• Most SVT arises from reentrant circuits or accessory pathways; triggers include stress, stimulants, and, less commonly, structural heart disease or genetic factors 2 6 9 10 11.
• Acute treatment starts with vagal maneuvers and adenosine; catheter ablation is the curative standard for frequent or severe cases 8 13 15 5 7 9 12.
• Pharmacologic therapy is reserved for select patients, with careful specialist oversight 2 7 9.
• Atrial flutter patients may require anticoagulation to prevent stroke 7.
• Early diagnosis and personalized treatment can restore quality of life and, in many cases, provide a complete cure.

If you suspect you have SVT or experience any of the symptoms discussed, consult a healthcare provider or heart rhythm specialist for evaluation and treatment tailored to your needs.